Suspension Fluid

2012-04-16T22:39:29Z

Pvd: /* Fox */

==What does the Suspension Fluid do?==

In addition to providing a lubricating and cooling bath for the dampers and bushings of the fork and shock to function in, the suspension fluid is the medium that is used to provide [[Damping|damping]] in a modern system.

Essentially, the oil is forced through an orifice or past a spring loaded shim to creating a resistive force to the action of the shocks. Aside from other changes that effect damping, the viscosity of the oil and how the viscosity changes as the oil heats up will be large factors in the system.

==Automatic Transmission Fluid (ATF)==
For years, ATF has been the standard fluid for damper rod forks. Why? Of all the commonly available automotive fluids capable of being used in the system, ATF is manufactured within a very, very tight and suitable viscosity range, esentially ISO 34.

This means that if you are in Florida or Mongolia, AFT is going to be available and consistant. This is a very important bit of information for the mechanic.

ATF is far too thick to be used in a modern cartridge damper fork. These forks tend to use oils in the ISO 16 range.

==Viscosity (ISO)==

Modern fluid viscosity ratings are on an ISO VG (visocosity grade) using test standards set down by [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D2422.htm?E+mystore ASTM D-2422-97 (2002)]& [http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8774&ICS1=75&ICS2=100&ICS3= ISO 3448:1992] system of: cSt@40C / cSt@100C / VI. ‘cSt’ stands for CentiStokes, an accurate dynamic measure of viscosity ([http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8252&ICS1=75&ICS2=80&ICS3= ISO 3104:1994] & [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D445.htm?L+mystore+gwao3944 ASTM D445-04]). Using these numbers, you can tune oil viscosity with a very high degree of precision in a specific heat range. A straight line graph made from these two viscosity numbers at each temperature can give a very close approximation of the oils viscosity at any other usable temperature.

[http://www.pvdwiki.com/images/0/09/Shell-ISO-grades.pdf ISO Grades] Courtesy of Shell Oil.
 

==SAE Oil Weight==
DO NOT GO BY LABLED OIL WEIGHT! Not only is this a poor way to decide which oil to use, but each manufacturer seems to be on a different scale. For example Maxima RSF 7wt is actually lighter than Spectro 5wt and Silkolene Pro RSF 7.5wt is actually heavier than Showa SS-8 10wt. This is not a judgment about the quality of these oils, just that the 'weight' label leads to a lot of trouble when trying to tune with suspension oils.

These problems can be seem graphically by comparing several systems to each other. [http://www.pvdwiki.com/images/c/cf/Shell-viscosity-comparison.pdf Viscosity comparison chart] Courtesy of Shell Oil.

Suspension oil is labeled by weight because consumers are used to thinking of oil (ie. motor oil & gear oil) in these terms. The SAE weight system has a very broad and vague viscosity range and does not even cover the viscosity range that most quality motorcycle suspension systems require. Another point of confusion is that motor oils and gear oils are rated for viscosity on the SAE scale at different temperatures, leading to similar viscosity oils having very different ratings. [http://www.sae.org/servlets/productDetail?PROD_TYP=STD&PROD_CD=J300_200405 SAE J300] is used to define engine oils, while [http://www.sae.org/technical/standards/J306_200506 SAE J306] is used to define drive line (gear) and chassis lubricants.

{| border="1" cellspacing="0" cellpadding="5" align="center"
! SAE Motor Oil Grade
! cSt @100C
|-
| 0W
| -3.8
|-
| 5W
| 3.8 - 4.1
|-
| 10W
| 4.1 - 5.6
|-
| 15W
| -5.6
|-
| ##W-20
| 9.3 - 12.5
|-
| ##W-40
| 12.5 - 16.3
|-
| ##W-50
| 16.3 - 21.9
|-
| ##W-60
| 21.9 - 26.1
|}

 

{| border="1" cellspacing="0" cellpadding="5" align="center"
! SAE Gear Oil Grade
! cSt @100C
|-
| 70W
| 4.1+
|-
| 75W
| 4.1+
|-
| 80W
| 7+
|-
| 85W
| 11+
|-
| 90W
| 13.5 - 24.5
|-
| 140W
| 24.0 - 41
|-
| 250W
| 41+
|}

==Saybolt Universal Second (SUS)==

Some oils are labeled on the SUS / VI (ie. 85/150) or Saybolt Universal Second / Viscosity Index. Although this is slightly better system than using SAE 'weights', the Saybolt Universal Second is considered antiquated, is vague and is not a valid viscosity reference. [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D88.htm?L+mystore+rybr7060 ASTM D88-94(1999)].

A rough conversion table from SUS grades is HERE. A very, very rough conversion table from SAE gear and motor oil grades is HERE.

<blockquote>[[Image:Cst-sus at 100C.gif]]</blockquote>

[http://www.pvdwiki.com/images/4/45/Shell-SUS-to-ISO.pdf Conversion from SUS to ISO] Courtesy of Shell. (Assumes VI of 95)

==Viscosity Index==
The Viscosity Index is very important in a suspension oil. “The viscosity index (V.I.) of an oil is a number that indicates the effect of temperature changes on the viscosity of the oil. A low V.I. signifies a relatively large change of viscosity with changes of temperature. In other words, the oil becomes extremely thin at high temperatures and extremely thick at low temperatures. On the other hand, a high V.I. signifies relatively little change in viscosity over a wide temperature range.” So specifically with regard to suspension, the greater the VI, the more consistent the damping will be over a large temp change.

ASTM D2270-04 Standard Practice for Calculating Viscosity Index From Kinematic Viscosity at 40 and 100°C

<blockquote>The Viscosity Index is calculated as such: 

[[Image:Vi-math.gif]] 

As Microsoft Excel sees it: 
VI = 100+(10^(LN((EXP(1.0727+0.6175*LN(cSt@100)+0.9744*(LN(cSt@100)^2)+(-0.3764)*(LN(cSt@100)^3)+0.04824*(LN(cSt@100)^4)))/cSt@40)/LN(cSt@100))-1)/0.00715

</blockquote>

On a lovely Sunday morning, the ambient temperature may be 21C (70F). Motorcycle forks will run in the 26C (78F) temp range, rear shocks will run in the 65C (150F) range and rear reservoirs will be around 43C (110F). While motorcycle rear shocks require very high VIs (over 300) to function well over such a huge temperature range, motorcycle forks and bicycles do not. Anything over 100VI will be serviceable for them.

==Synthetic, Mineral, and additives==

Some suspension oils are synthetic vs. mineral. These are very high quality oils and most general service applications do not require their use. You should, however, consider synthetic oil for performance applications. My Penske rear shock does require a full synthetic oil. Most oils on the market are either full mineral oil or a blend of mineral and synthetic oils. Almost all suspension oils will contain viscosity modifiers, seal conditioners, and anti-foam agents.
==Generalities==
Most cartridge type forks use a viscosity of 16 cSt@40C. (Except for Ohlins R&T, 19 cSt@40)
Most damper rod type forks are specd for a viscosity of 34 cSt@40C. (Basically ATF Fluid) although most setups require far thicker for adequate performance.

Ohlins Steering damper use 16 cSt @40C for street and 19 cSt@40C for enduro and MX

Ohlins Shocks get set up with Öhlins Shock Absorber Fluid No. 309 (#01306-01) (13.7 cSt@40)
Penske Shocks get set up with Silkolene Pro RSF (5wt) (26.7 cSt@40)

==Comercial Brands and their properties==

The oil in a bike's fork or shock not only cools and lubricates the system, but is the heart of all the damping control available for the springs. All phases of the damping involve the viscosity of the oil used in the system. Oil is such a critical suspension tuning decision that is the first priority to get worked out after spring/sag choice. No matter what all of your friends say about what the greatest high speed valves are or wild shim stacks, you should agonize over oil choice. In general, Use the least viscous oil possible that produces good slow speed damping performance with the damping adjustment screws out 1 full turn from full closed. This ensures that a fair amount of fine tuning will be available for track and weather conditions.

I suggest using either [http://www.silkolene.com/ Silkolene Pro RSF] ([http://www.pvdwiki.com/images/a/aa/Silkolene_Pro_RSF.pdf PDS])(ester) or [http://www.redlineoil.com/ Red Line] ([http://www.redlineoil.com/pdf/10.pdf PDS])(polyol ester) synthetic suspension oils for front and rear suspension systems. They both have very high VI numbers and have enough of a viscosity selection to produce any mix you may need. You should, however, stay with one brand whichever way you go. I have decided to use Red Line exclusively. They range from extremely thin to extremely thick, in five different viscosities. They make the oil in nearby Benicia, CA and the oils come in really pretty colors.

 

Viscosity, ASTM D445 (cSt) & ASTM D2270 (VI)
{| border="1" cellspacing="0" cellpadding="5" align="center"
! Brand
! cSt @ 40C
! cSt @ 100C
! VI
|-
|Red Line (Like Water!, Clear)
| 5.50
| 2.30
| 344.00
|-
|Red Line (Extra Light, Blue)
| 9.80
| 4.00
| 402.00
|-
|Silkolene Pro RSF (2.5wt)
| 13.60
| 5.83
| 464.00
|-
|Red Line (Light, Yellow)
| 18.40
| 7.10
| 407.00
|-
|Silkolene Pro RSF (5wt)
| 26.70
| 9.46
| 372.00
|-
|Red Line (Medium, Red)
| 30.40
| 10.80
| 369.00
|-
|Silkolene Pro RSF (7.5wt)
| 37.00
| 12.00
| 322.00
|-
|Silkolene Pro RSF (10wt)
| 47.36
| 13.69
| 303.00
|-
|Red Line (Heavy)
| 66.80
| 16.00
| 256.00
|-
|Silkolene Pro RSF (15wt)
| 92.95
| 19.50
| 235.00
|}

Suspension fluid must be changed often for optimum performance. Rear shock oil suffers from thermal breakdown due to the extreme temperatures that they operate in and shear forces under high load (hydrocracking). The fork does not suffer from this but does suffer from massive amounts of contamination from inside and outside.One more very important point must be made when talking about oil tuning. While tires may take around 10 minutes to reach their full running temperature, the rear shock on a motorcycle can take upwards of 30 minutes to fully heat up. This being the case, you should not attempt to change any settings in the suspension or make any decisions on which direction to go with oil viscosity until the bike has been ridden hard for at least 30 minutes.

[[Image:PVD-ISO-Viscosity-Data.gif]]

==Mixing Suspension Fluids==

Suspension fluids can be mixed my targeting a specific kinematic viscosity at a specific temperature. Since the componenent fluids maintain a fairly straight line change in viscosity as temperature changes, a ratio mix can be devised. Accurate mixing of viscous fluids requires application or the [http://en.wikipedia.org/wiki/Viscosity#Viscosity_of_blends_of_liquids Refutas Equation]

These two charts were prepared for Red Line and Silkolene oils:

[http://www.pvdwiki.com/images/7/7f/Red_Line_Mix_Chart.pdf Red-Line-mix.pdf] 
[http://www.pvdwiki.com/images/c/c3/Silkolene_Mix_Chart.pdf Silkolene-mix.pdf]

Or you can go to Jay Lee's (jayz28 @ MTBR.com) website for a web based calculator. http://www.provire.com/index.php/mtb

==Bicycle Fluids==
===Rock Shox===
Rock Shocks OE fluid was Torco. They have since changed to [http://www.maximausa.com/products/suspension/forkfluid.asp Maxima 85-150] Fork Fluid for damping on most forks. 15.9 cSt.

Totem uses Maxima 235-150 for lubrication and 2.5 wt (?) for damping.

===Fox===
*025-03-004-A Fox Suspension Fluid 32 oz bottle 7wt. (replaced by 025-03-008)
*025-02-003 Fox Suspension Fluid (red)32 oz bottle 10wt. 47.36 @40, 15.69@100, 303 VI (essentially Silkolene Pro RSF 10wt)
*025-03-008 Fox Suspension Fluid (green)32 oz bottle 10wt. 47.00 @40, 11.7@100

===Marzocchi===
Stock oil is Spectro.
Rumours of Silkolene causing problems in Marzocchi forks exist. Be careful using this mix.

Marzocchi Oil- Marzocchi Bomber Factory Fork Oil comes stock in all bomber forks. It is synthetic and is labeled as being 7.5wt. While this oil can be ordered in the US, Marzocchi is basically repackaging Golden Spectro Cartridge Fork Fluid (125/150, Very Light). This oil is rated at 26.1 cSt@40C/5.25 cSt@100C/VI 150. A very similar oil to this is Maxima Racing Fork Fluid (125/150, 7wt). It would be preferred to run a mix of Red Line Synthetic Fork Oil of 37% Red Line (Light, Yellow) & 63% Red Line (Medium, Red). In the past I have found Marzocchi forks to work far better with a thicker oil in them.

===Answer/Manitou Oil===
Manitou forks use, for lubrication, Motorex Semi-Bath Fork Oil, 5W40 from Motorex of Switzerland. This is actually Motorex Motor Oil Power Synt 4T SAE 5W40, a synthetic motor oil. This oil is rated at 90.9 cSt@40C/14.6 cSt@100C/VI 169. This is some serious pancake syrup. This oil is not widely available, but can be ordered at most motorcycle dealers through K&L Supply Co. (PN# 35-3911). Similar oils do not really exist as suspension oils. Closest is Red Line (Heavy) (66.8 cSt@40C/16 cSt@100C/VI 256) or Maxima Bicycle Fork Fluid (20wt) or Maxima Fork Oil (20wt) both of which are rated at 65 cSt@40C/12.9 cSt@100C/VI 201. If you can get access to Red Line Synthetic Motor Oil 5W40, it is rated at 94 cSt@40C/15.1 cSt@100C/VI 170 and is probably your closest bet.

==External Links==

[http://en.wikipedia.org/wiki/Viscosity Wikipedia - Viscosity] 
[http://en.wikipedia.org/wiki/Viscosity_index Wikipedia - Viscosity Index] 
 
[http://www.sae.org The Society of Automotive Engineers (SAE)]

[[Category:Bicycle]]
[[Category:Suspension (Bicycle)]]
[[Category:Motorcycle]]
[[Category:Suspension (Motorcycle)]]

Suspension Fluid

2012-04-16T22:37:31Z

2011-02-10T21:34:54Z

Pvd: /* Mixing Suspension Fluids */

==What does the Suspension Fluid do?==

In addition to providing a lubricating and cooling bath for the dampers and bushings of the fork and shock to function in, the suspension fluid is the medium that is used to provide [[Damping|damping]] in a modern system.

Essentially, the oil is forced through an orifice or past a spring loaded shim to creating a resistive force to the action of the shocks. Aside from other changes that effect damping, the viscosity of the oil and how the viscosity changes as the oil heats up will be large factors in the system.

==Automatic Transmission Fluid (ATF)==
For years, ATF has been the standard fluid for damper rod forks. Why? Of all the commonly available automotive fluids capable of being used in the system, ATF is manufactured within a very, very tight and suitable viscosity range, esentially ISO 34.

This means that if you are in Florida or Mongolia, AFT is going to be available and consistant. This is a very important bit of information for the mechanic.

ATF is far too thick to be used in a modern cartridge damper fork. These forks tend to use oils in the ISO 16 range.

==Viscosity (ISO)==

Modern fluid viscosity ratings are on an ISO VG (visocosity grade) using test standards set down by [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D2422.htm?E+mystore ASTM D-2422-97 (2002)]& [http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8774&ICS1=75&ICS2=100&ICS3= ISO 3448:1992] system of: cSt@40C / cSt@100C / VI. ‘cSt’ stands for CentiStokes, an accurate dynamic measure of viscosity ([http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8252&ICS1=75&ICS2=80&ICS3= ISO 3104:1994] & [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D445.htm?L+mystore+gwao3944 ASTM D445-04]). Using these numbers, you can tune oil viscosity with a very high degree of precision in a specific heat range. A straight line graph made from these two viscosity numbers at each temperature can give a very close approximation of the oils viscosity at any other usable temperature.

[http://www.pvdwiki.com/images/0/09/Shell-ISO-grades.pdf ISO Grades] Courtesy of Shell Oil.
 

==SAE Oil Weight==
DO NOT GO BY LABLED OIL WEIGHT! Not only is this a poor way to decide which oil to use, but each manufacturer seems to be on a different scale. For example Maxima RSF 7wt is actually lighter than Spectro 5wt and Silkolene Pro RSF 7.5wt is actually heavier than Showa SS-8 10wt. This is not a judgment about the quality of these oils, just that the 'weight' label leads to a lot of trouble when trying to tune with suspension oils.

These problems can be seem graphically by comparing several systems to each other. [http://www.pvdwiki.com/images/c/cf/Shell-viscosity-comparison.pdf Viscosity comparison chart] Courtesy of Shell Oil.

Suspension oil is labeled by weight because consumers are used to thinking of oil (ie. motor oil & gear oil) in these terms. The SAE weight system has a very broad and vague viscosity range and does not even cover the viscosity range that most quality motorcycle suspension systems require. Another point of confusion is that motor oils and gear oils are rated for viscosity on the SAE scale at different temperatures, leading to similar viscosity oils having very different ratings. [http://www.sae.org/servlets/productDetail?PROD_TYP=STD&PROD_CD=J300_200405 SAE J300] is used to define engine oils, while [http://www.sae.org/technical/standards/J306_200506 SAE J306] is used to define drive line (gear) and chassis lubricants.

{| border="1" cellspacing="0" cellpadding="5" align="center"
! SAE Motor Oil Grade
! cSt @100C
|-
| 0W
| -3.8
|-
| 5W
| 3.8 - 4.1
|-
| 10W
| 4.1 - 5.6
|-
| 15W
| -5.6
|-
| ##W-20
| 9.3 - 12.5
|-
| ##W-40
| 12.5 - 16.3
|-
| ##W-50
| 16.3 - 21.9
|-
| ##W-60
| 21.9 - 26.1
|}

 

{| border="1" cellspacing="0" cellpadding="5" align="center"
! SAE Gear Oil Grade
! cSt @100C
|-
| 70W
| 4.1+
|-
| 75W
| 4.1+
|-
| 80W
| 7+
|-
| 85W
| 11+
|-
| 90W
| 13.5 - 24.5
|-
| 140W
| 24.0 - 41
|-
| 250W
| 41+
|}

==Saybolt Universal Second (SUS)==

Some oils are labeled on the SUS / VI (ie. 85/150) or Saybolt Universal Second / Viscosity Index. Although this is slightly better system than using SAE 'weights', the Saybolt Universal Second is considered antiquated, is vague and is not a valid viscosity reference. [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D88.htm?L+mystore+rybr7060 ASTM D88-94(1999)].

A rough conversion table from SUS grades is HERE. A very, very rough conversion table from SAE gear and motor oil grades is HERE.

<blockquote>[[Image:Cst-sus at 100C.gif]]</blockquote>

[http://www.pvdwiki.com/images/4/45/Shell-SUS-to-ISO.pdf Conversion from SUS to ISO] Courtesy of Shell. (Assumes VI of 95)

==Viscosity Index==
The Viscosity Index is very important in a suspension oil. “The viscosity index (V.I.) of an oil is a number that indicates the effect of temperature changes on the viscosity of the oil. A low V.I. signifies a relatively large change of viscosity with changes of temperature. In other words, the oil becomes extremely thin at high temperatures and extremely thick at low temperatures. On the other hand, a high V.I. signifies relatively little change in viscosity over a wide temperature range.” So specifically with regard to suspension, the greater the VI, the more consistent the damping will be over a large temp change.

ASTM D2270-04 Standard Practice for Calculating Viscosity Index From Kinematic Viscosity at 40 and 100°C

<blockquote>The Viscosity Index is calculated as such: 

[[Image:Vi-math.gif]] 

As Microsoft Excel sees it: 
VI = 100+(10^(LN((EXP(1.0727+0.6175*LN(cSt@100)+0.9744*(LN(cSt@100)^2)+(-0.3764)*(LN(cSt@100)^3)+0.04824*(LN(cSt@100)^4)))/cSt@40)/LN(cSt@100))-1)/0.00715

</blockquote>

On a lovely Sunday morning, the ambient temperature may be 21C (70F). Motorcycle forks will run in the 26C (78F) temp range, rear shocks will run in the 65C (150F) range and rear reservoirs will be around 43C (110F). While motorcycle rear shocks require very high VIs (over 300) to function well over such a huge temperature range, motorcycle forks and bicycles do not. Anything over 100VI will be serviceable for them.

==Synthetic, Mineral, and additives==

Some suspension oils are synthetic vs. mineral. These are very high quality oils and most general service applications do not require their use. You should, however, consider synthetic oil for performance applications. My Penske rear shock does require a full synthetic oil. Most oils on the market are either full mineral oil or a blend of mineral and synthetic oils. Almost all suspension oils will contain viscosity modifiers, seal conditioners, and anti-foam agents.
==Generalities==
Most cartridge type forks use a viscosity of 16 cSt@40C. (Except for Ohlins R&T, 19 cSt@40)
Most damper rod type forks are specd for a viscosity of 34 cSt@40C. (Basically ATF Fluid) although most setups require far thicker for adequate performance.

Ohlins Steering damper use 16 cSt @40C for street and 19 cSt@40C for enduro and MX

Ohlins Shocks get set up with Öhlins Shock Absorber Fluid No. 309 (#01306-01) (13.7 cSt@40)
Penske Shocks get set up with Silkolene Pro RSF (5wt) (26.7 cSt@40)

==Comercial Brands and their properties==

The oil in a bike's fork or shock not only cools and lubricates the system, but is the heart of all the damping control available for the springs. All phases of the damping involve the viscosity of the oil used in the system. Oil is such a critical suspension tuning decision that is the first priority to get worked out after spring/sag choice. No matter what all of your friends say about what the greatest high speed valves are or wild shim stacks, you should agonize over oil choice. In general, Use the least viscous oil possible that produces good slow speed damping performance with the damping adjustment screws out 1 full turn from full closed. This ensures that a fair amount of fine tuning will be available for track and weather conditions.

I suggest using either [http://www.silkolene.com/ Silkolene Pro RSF] ([http://www.pvdwiki.com/images/a/aa/Silkolene_Pro_RSF.pdf PDS])(ester) or [http://www.redlineoil.com/ Red Line] ([http://www.redlineoil.com/pdf/10.pdf PDS])(polyol ester) synthetic suspension oils for front and rear suspension systems. They both have very high VI numbers and have enough of a viscosity selection to produce any mix you may need. You should, however, stay with one brand whichever way you go. I have decided to use Red Line exclusively. They range from extremely thin to extremely thick, in five different viscosities. They make the oil in nearby Benicia, CA and the oils come in really pretty colors.

 

Viscosity, ASTM D445 (cSt) & ASTM D2270 (VI)
{| border="1" cellspacing="0" cellpadding="5" align="center"
! Brand
! cSt @ 40C
! cSt @ 100C
! VI
|-
|Red Line (Like Water!, Clear)
| 5.50
| 2.30
| 344.00
|-
|Red Line (Extra Light, Blue)
| 9.80
| 4.00
| 402.00
|-
|Silkolene Pro RSF (2.5wt)
| 13.60
| 5.83
| 464.00
|-
|Red Line (Light, Yellow)
| 18.40
| 7.10
| 407.00
|-
|Silkolene Pro RSF (5wt)
| 26.70
| 9.46
| 372.00
|-
|Red Line (Medium, Red)
| 30.40
| 10.80
| 369.00
|-
|Silkolene Pro RSF (7.5wt)
| 37.00
| 12.00
| 322.00
|-
|Silkolene Pro RSF (10wt)
| 47.36
| 13.69
| 303.00
|-
|Red Line (Heavy)
| 66.80
| 16.00
| 256.00
|-
|Silkolene Pro RSF (15wt)
| 92.95
| 19.50
| 235.00
|}

Suspension fluid must be changed often for optimum performance. Rear shock oil suffers from thermal breakdown due to the extreme temperatures that they operate in and shear forces under high load (hydrocracking). The fork does not suffer from this but does suffer from massive amounts of contamination from inside and outside.One more very important point must be made when talking about oil tuning. While tires may take around 10 minutes to reach their full running temperature, the rear shock on a motorcycle can take upwards of 30 minutes to fully heat up. This being the case, you should not attempt to change any settings in the suspension or make any decisions on which direction to go with oil viscosity until the bike has been ridden hard for at least 30 minutes.

[[Image:PVD-ISO-Viscosity-Data.gif]]

==Mixing Suspension Fluids==

Suspension fluids can be mixed my targeting a specific kinematic viscosity at a specific temperature. Since the componenent fluids maintain a fairly straight line change in viscosity as temperature changes, a ratio mix can be devised. Accurate mixing of viscous fluids requires application or the [[http://en.wikipedia.org/wiki/Viscosity#Viscosity_of_blends_of_liquids
Refutas Equation]]

These two charts were prepared for Red Line and Silkolene oils:

[http://www.pvdwiki.com/images/7/7f/Red_Line_Mix_Chart.pdf Red-Line-mix.pdf] 
[http://www.pvdwiki.com/images/c/c3/Silkolene_Mix_Chart.pdf Silkolene-mix.pdf]

Or you can go to Jay Lee's (jayz28 @ MTBR.com) website for a web based calculator. http://www.provire.com/index.php/mtb

==Bicycle Fluids==
===Rock Shox===
Rock Shocks OE fluid was Torco. They have since changed to [http://www.maximausa.com/products/suspension/forkfluid.asp Maxima 85-150] Fork Fluid for damping on most forks. 15.9 cSt.

Totem uses Maxima 235-150 for lubrication and 2.5 wt (?) for damping.

===Fox===
*025-03-004-A Fox Suspension Fluid 32 oz bottle 7wt.
*025-02-003 Fox Suspension Fluid 32 oz bottle 10wt.

===Marzocchi===
Stock oil is Spectro.
Rumours of Silkolene causing problems in Marzocchi forks exist. Be careful using this mix.

Marzocchi Oil- Marzocchi Bomber Factory Fork Oil comes stock in all bomber forks. It is synthetic and is labeled as being 7.5wt. While this oil can be ordered in the US, Marzocchi is basically repackaging Golden Spectro Cartridge Fork Fluid (125/150, Very Light). This oil is rated at 26.1 cSt@40C/5.25 cSt@100C/VI 150. A very similar oil to this is Maxima Racing Fork Fluid (125/150, 7wt). It would be preferred to run a mix of Red Line Synthetic Fork Oil of 37% Red Line (Light, Yellow) & 63% Red Line (Medium, Red). In the past I have found Marzocchi forks to work far better with a thicker oil in them.

===Answer/Manitou Oil===
Manitou forks use, for lubrication, Motorex Semi-Bath Fork Oil, 5W40 from Motorex of Switzerland. This is actually Motorex Motor Oil Power Synt 4T SAE 5W40, a synthetic motor oil. This oil is rated at 90.9 cSt@40C/14.6 cSt@100C/VI 169. This is some serious pancake syrup. This oil is not widely available, but can be ordered at most motorcycle dealers through K&L Supply Co. (PN# 35-3911). Similar oils do not really exist as suspension oils. Closest is Red Line (Heavy) (66.8 cSt@40C/16 cSt@100C/VI 256) or Maxima Bicycle Fork Fluid (20wt) or Maxima Fork Oil (20wt) both of which are rated at 65 cSt@40C/12.9 cSt@100C/VI 201. If you can get access to Red Line Synthetic Motor Oil 5W40, it is rated at 94 cSt@40C/15.1 cSt@100C/VI 170 and is probably your closest bet.

==External Links==

[http://en.wikipedia.org/wiki/Viscosity Wikipedia - Viscosity] 
[http://en.wikipedia.org/wiki/Viscosity_index Wikipedia - Viscosity Index] 
 
[http://www.sae.org The Society of Automotive Engineers (SAE)]

[[Category:Bicycle]]
[[Category:Suspension (Bicycle)]]
[[Category:Motorcycle]]
[[Category:Suspension (Motorcycle)]]

Suspension Fluid

2011-02-10T21:34:07Z

Pvd: /* Mixing Suspension Fluids */

==What does the Suspension Fluid do?==

In addition to providing a lubricating and cooling bath for the dampers and bushings of the fork and shock to function in, the suspension fluid is the medium that is used to provide [[Damping|damping]] in a modern system.

Essentially, the oil is forced through an orifice or past a spring loaded shim to creating a resistive force to the action of the shocks. Aside from other changes that effect damping, the viscosity of the oil and how the viscosity changes as the oil heats up will be large factors in the system.

==Automatic Transmission Fluid (ATF)==
For years, ATF has been the standard fluid for damper rod forks. Why? Of all the commonly available automotive fluids capable of being used in the system, ATF is manufactured within a very, very tight and suitable viscosity range, esentially ISO 34.

This means that if you are in Florida or Mongolia, AFT is going to be available and consistant. This is a very important bit of information for the mechanic.

ATF is far too thick to be used in a modern cartridge damper fork. These forks tend to use oils in the ISO 16 range.

==Viscosity (ISO)==

Modern fluid viscosity ratings are on an ISO VG (visocosity grade) using test standards set down by [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D2422.htm?E+mystore ASTM D-2422-97 (2002)]& [http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8774&ICS1=75&ICS2=100&ICS3= ISO 3448:1992] system of: cSt@40C / cSt@100C / VI. ‘cSt’ stands for CentiStokes, an accurate dynamic measure of viscosity ([http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8252&ICS1=75&ICS2=80&ICS3= ISO 3104:1994] & [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D445.htm?L+mystore+gwao3944 ASTM D445-04]). Using these numbers, you can tune oil viscosity with a very high degree of precision in a specific heat range. A straight line graph made from these two viscosity numbers at each temperature can give a very close approximation of the oils viscosity at any other usable temperature.

[http://www.pvdwiki.com/images/0/09/Shell-ISO-grades.pdf ISO Grades] Courtesy of Shell Oil.
 

==SAE Oil Weight==
DO NOT GO BY LABLED OIL WEIGHT! Not only is this a poor way to decide which oil to use, but each manufacturer seems to be on a different scale. For example Maxima RSF 7wt is actually lighter than Spectro 5wt and Silkolene Pro RSF 7.5wt is actually heavier than Showa SS-8 10wt. This is not a judgment about the quality of these oils, just that the 'weight' label leads to a lot of trouble when trying to tune with suspension oils.

These problems can be seem graphically by comparing several systems to each other. [http://www.pvdwiki.com/images/c/cf/Shell-viscosity-comparison.pdf Viscosity comparison chart] Courtesy of Shell Oil.

Suspension oil is labeled by weight because consumers are used to thinking of oil (ie. motor oil & gear oil) in these terms. The SAE weight system has a very broad and vague viscosity range and does not even cover the viscosity range that most quality motorcycle suspension systems require. Another point of confusion is that motor oils and gear oils are rated for viscosity on the SAE scale at different temperatures, leading to similar viscosity oils having very different ratings. [http://www.sae.org/servlets/productDetail?PROD_TYP=STD&PROD_CD=J300_200405 SAE J300] is used to define engine oils, while [http://www.sae.org/technical/standards/J306_200506 SAE J306] is used to define drive line (gear) and chassis lubricants.

{| border="1" cellspacing="0" cellpadding="5" align="center"
! SAE Motor Oil Grade
! cSt @100C
|-
| 0W
| -3.8
|-
| 5W
| 3.8 - 4.1
|-
| 10W
| 4.1 - 5.6
|-
| 15W
| -5.6
|-
| ##W-20
| 9.3 - 12.5
|-
| ##W-40
| 12.5 - 16.3
|-
| ##W-50
| 16.3 - 21.9
|-
| ##W-60
| 21.9 - 26.1
|}

 

{| border="1" cellspacing="0" cellpadding="5" align="center"
! SAE Gear Oil Grade
! cSt @100C
|-
| 70W
| 4.1+
|-
| 75W
| 4.1+
|-
| 80W
| 7+
|-
| 85W
| 11+
|-
| 90W
| 13.5 - 24.5
|-
| 140W
| 24.0 - 41
|-
| 250W
| 41+
|}

==Saybolt Universal Second (SUS)==

Some oils are labeled on the SUS / VI (ie. 85/150) or Saybolt Universal Second / Viscosity Index. Although this is slightly better system than using SAE 'weights', the Saybolt Universal Second is considered antiquated, is vague and is not a valid viscosity reference. [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D88.htm?L+mystore+rybr7060 ASTM D88-94(1999)].

A rough conversion table from SUS grades is HERE. A very, very rough conversion table from SAE gear and motor oil grades is HERE.

<blockquote>[[Image:Cst-sus at 100C.gif]]</blockquote>

[http://www.pvdwiki.com/images/4/45/Shell-SUS-to-ISO.pdf Conversion from SUS to ISO] Courtesy of Shell. (Assumes VI of 95)

==Viscosity Index==
The Viscosity Index is very important in a suspension oil. “The viscosity index (V.I.) of an oil is a number that indicates the effect of temperature changes on the viscosity of the oil. A low V.I. signifies a relatively large change of viscosity with changes of temperature. In other words, the oil becomes extremely thin at high temperatures and extremely thick at low temperatures. On the other hand, a high V.I. signifies relatively little change in viscosity over a wide temperature range.” So specifically with regard to suspension, the greater the VI, the more consistent the damping will be over a large temp change.

ASTM D2270-04 Standard Practice for Calculating Viscosity Index From Kinematic Viscosity at 40 and 100°C

<blockquote>The Viscosity Index is calculated as such: 

[[Image:Vi-math.gif]] 

As Microsoft Excel sees it: 
VI = 100+(10^(LN((EXP(1.0727+0.6175*LN(cSt@100)+0.9744*(LN(cSt@100)^2)+(-0.3764)*(LN(cSt@100)^3)+0.04824*(LN(cSt@100)^4)))/cSt@40)/LN(cSt@100))-1)/0.00715

</blockquote>

On a lovely Sunday morning, the ambient temperature may be 21C (70F). Motorcycle forks will run in the 26C (78F) temp range, rear shocks will run in the 65C (150F) range and rear reservoirs will be around 43C (110F). While motorcycle rear shocks require very high VIs (over 300) to function well over such a huge temperature range, motorcycle forks and bicycles do not. Anything over 100VI will be serviceable for them.

==Synthetic, Mineral, and additives==

Some suspension oils are synthetic vs. mineral. These are very high quality oils and most general service applications do not require their use. You should, however, consider synthetic oil for performance applications. My Penske rear shock does require a full synthetic oil. Most oils on the market are either full mineral oil or a blend of mineral and synthetic oils. Almost all suspension oils will contain viscosity modifiers, seal conditioners, and anti-foam agents.
==Generalities==
Most cartridge type forks use a viscosity of 16 cSt@40C. (Except for Ohlins R&T, 19 cSt@40)
Most damper rod type forks are specd for a viscosity of 34 cSt@40C. (Basically ATF Fluid) although most setups require far thicker for adequate performance.

Ohlins Steering damper use 16 cSt @40C for street and 19 cSt@40C for enduro and MX

Ohlins Shocks get set up with Öhlins Shock Absorber Fluid No. 309 (#01306-01) (13.7 cSt@40)
Penske Shocks get set up with Silkolene Pro RSF (5wt) (26.7 cSt@40)

==Comercial Brands and their properties==

The oil in a bike's fork or shock not only cools and lubricates the system, but is the heart of all the damping control available for the springs. All phases of the damping involve the viscosity of the oil used in the system. Oil is such a critical suspension tuning decision that is the first priority to get worked out after spring/sag choice. No matter what all of your friends say about what the greatest high speed valves are or wild shim stacks, you should agonize over oil choice. In general, Use the least viscous oil possible that produces good slow speed damping performance with the damping adjustment screws out 1 full turn from full closed. This ensures that a fair amount of fine tuning will be available for track and weather conditions.

I suggest using either [http://www.silkolene.com/ Silkolene Pro RSF] ([http://www.pvdwiki.com/images/a/aa/Silkolene_Pro_RSF.pdf PDS])(ester) or [http://www.redlineoil.com/ Red Line] ([http://www.redlineoil.com/pdf/10.pdf PDS])(polyol ester) synthetic suspension oils for front and rear suspension systems. They both have very high VI numbers and have enough of a viscosity selection to produce any mix you may need. You should, however, stay with one brand whichever way you go. I have decided to use Red Line exclusively. They range from extremely thin to extremely thick, in five different viscosities. They make the oil in nearby Benicia, CA and the oils come in really pretty colors.

 

Viscosity, ASTM D445 (cSt) & ASTM D2270 (VI)
{| border="1" cellspacing="0" cellpadding="5" align="center"
! Brand
! cSt @ 40C
! cSt @ 100C
! VI
|-
|Red Line (Like Water!, Clear)
| 5.50
| 2.30
| 344.00
|-
|Red Line (Extra Light, Blue)
| 9.80
| 4.00
| 402.00
|-
|Silkolene Pro RSF (2.5wt)
| 13.60
| 5.83
| 464.00
|-
|Red Line (Light, Yellow)
| 18.40
| 7.10
| 407.00
|-
|Silkolene Pro RSF (5wt)
| 26.70
| 9.46
| 372.00
|-
|Red Line (Medium, Red)
| 30.40
| 10.80
| 369.00
|-
|Silkolene Pro RSF (7.5wt)
| 37.00
| 12.00
| 322.00
|-
|Silkolene Pro RSF (10wt)
| 47.36
| 13.69
| 303.00
|-
|Red Line (Heavy)
| 66.80
| 16.00
| 256.00
|-
|Silkolene Pro RSF (15wt)
| 92.95
| 19.50
| 235.00
|}

Suspension fluid must be changed often for optimum performance. Rear shock oil suffers from thermal breakdown due to the extreme temperatures that they operate in and shear forces under high load (hydrocracking). The fork does not suffer from this but does suffer from massive amounts of contamination from inside and outside.One more very important point must be made when talking about oil tuning. While tires may take around 10 minutes to reach their full running temperature, the rear shock on a motorcycle can take upwards of 30 minutes to fully heat up. This being the case, you should not attempt to change any settings in the suspension or make any decisions on which direction to go with oil viscosity until the bike has been ridden hard for at least 30 minutes.

[[Image:PVD-ISO-Viscosity-Data.gif]]

==Mixing Suspension Fluids==

Suspension fluids can be mixed my targeting a specific kinematic viscosity at a specific temperature. Since the componenent fluids maintain a fairly straight line change in viscosity as temperature changes, a ratio mix can be devised. Accurate mixing of viscous fluids requires application or the [http://en.wikipedia.org/wiki/Viscosity#Viscosity_of_blends_of_liquids
Refutas Equation]

These two charts were prepared for Red Line and Silkolene oils:

[http://www.pvdwiki.com/images/7/7f/Red_Line_Mix_Chart.pdf Red-Line-mix.pdf] 
[http://www.pvdwiki.com/images/c/c3/Silkolene_Mix_Chart.pdf Silkolene-mix.pdf]

Or you can go to Jay Lee's (jayz28 @ MTBR.com) website for a web based calculator. http://www.provire.com/index.php/mtb

==Bicycle Fluids==
===Rock Shox===
Rock Shocks OE fluid was Torco. They have since changed to [http://www.maximausa.com/products/suspension/forkfluid.asp Maxima 85-150] Fork Fluid for damping on most forks. 15.9 cSt.

Totem uses Maxima 235-150 for lubrication and 2.5 wt (?) for damping.

===Fox===
*025-03-004-A Fox Suspension Fluid 32 oz bottle 7wt.
*025-02-003 Fox Suspension Fluid 32 oz bottle 10wt.

===Marzocchi===
Stock oil is Spectro.
Rumours of Silkolene causing problems in Marzocchi forks exist. Be careful using this mix.

Marzocchi Oil- Marzocchi Bomber Factory Fork Oil comes stock in all bomber forks. It is synthetic and is labeled as being 7.5wt. While this oil can be ordered in the US, Marzocchi is basically repackaging Golden Spectro Cartridge Fork Fluid (125/150, Very Light). This oil is rated at 26.1 cSt@40C/5.25 cSt@100C/VI 150. A very similar oil to this is Maxima Racing Fork Fluid (125/150, 7wt). It would be preferred to run a mix of Red Line Synthetic Fork Oil of 37% Red Line (Light, Yellow) & 63% Red Line (Medium, Red). In the past I have found Marzocchi forks to work far better with a thicker oil in them.

===Answer/Manitou Oil===
Manitou forks use, for lubrication, Motorex Semi-Bath Fork Oil, 5W40 from Motorex of Switzerland. This is actually Motorex Motor Oil Power Synt 4T SAE 5W40, a synthetic motor oil. This oil is rated at 90.9 cSt@40C/14.6 cSt@100C/VI 169. This is some serious pancake syrup. This oil is not widely available, but can be ordered at most motorcycle dealers through K&L Supply Co. (PN# 35-3911). Similar oils do not really exist as suspension oils. Closest is Red Line (Heavy) (66.8 cSt@40C/16 cSt@100C/VI 256) or Maxima Bicycle Fork Fluid (20wt) or Maxima Fork Oil (20wt) both of which are rated at 65 cSt@40C/12.9 cSt@100C/VI 201. If you can get access to Red Line Synthetic Motor Oil 5W40, it is rated at 94 cSt@40C/15.1 cSt@100C/VI 170 and is probably your closest bet.

==External Links==

[http://en.wikipedia.org/wiki/Viscosity Wikipedia - Viscosity] 
[http://en.wikipedia.org/wiki/Viscosity_index Wikipedia - Viscosity Index] 
 
[http://www.sae.org The Society of Automotive Engineers (SAE)]

[[Category:Bicycle]]
[[Category:Suspension (Bicycle)]]
[[Category:Motorcycle]]
[[Category:Suspension (Motorcycle)]]

Suspension Fluid

2011-02-10T21:32:27Z

Pvd: /* Mixing Suspension Fluids */

==What does the Suspension Fluid do?==

In addition to providing a lubricating and cooling bath for the dampers and bushings of the fork and shock to function in, the suspension fluid is the medium that is used to provide [[Damping|damping]] in a modern system.

Essentially, the oil is forced through an orifice or past a spring loaded shim to creating a resistive force to the action of the shocks. Aside from other changes that effect damping, the viscosity of the oil and how the viscosity changes as the oil heats up will be large factors in the system.

==Automatic Transmission Fluid (ATF)==
For years, ATF has been the standard fluid for damper rod forks. Why? Of all the commonly available automotive fluids capable of being used in the system, ATF is manufactured within a very, very tight and suitable viscosity range, esentially ISO 34.

This means that if you are in Florida or Mongolia, AFT is going to be available and consistant. This is a very important bit of information for the mechanic.

ATF is far too thick to be used in a modern cartridge damper fork. These forks tend to use oils in the ISO 16 range.

==Viscosity (ISO)==

Modern fluid viscosity ratings are on an ISO VG (visocosity grade) using test standards set down by [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D2422.htm?E+mystore ASTM D-2422-97 (2002)]& [http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8774&ICS1=75&ICS2=100&ICS3= ISO 3448:1992] system of: cSt@40C / cSt@100C / VI. ‘cSt’ stands for CentiStokes, an accurate dynamic measure of viscosity ([http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8252&ICS1=75&ICS2=80&ICS3= ISO 3104:1994] & [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D445.htm?L+mystore+gwao3944 ASTM D445-04]). Using these numbers, you can tune oil viscosity with a very high degree of precision in a specific heat range. A straight line graph made from these two viscosity numbers at each temperature can give a very close approximation of the oils viscosity at any other usable temperature.

[http://www.pvdwiki.com/images/0/09/Shell-ISO-grades.pdf ISO Grades] Courtesy of Shell Oil.
 

==SAE Oil Weight==
DO NOT GO BY LABLED OIL WEIGHT! Not only is this a poor way to decide which oil to use, but each manufacturer seems to be on a different scale. For example Maxima RSF 7wt is actually lighter than Spectro 5wt and Silkolene Pro RSF 7.5wt is actually heavier than Showa SS-8 10wt. This is not a judgment about the quality of these oils, just that the 'weight' label leads to a lot of trouble when trying to tune with suspension oils.

These problems can be seem graphically by comparing several systems to each other. [http://www.pvdwiki.com/images/c/cf/Shell-viscosity-comparison.pdf Viscosity comparison chart] Courtesy of Shell Oil.

Suspension oil is labeled by weight because consumers are used to thinking of oil (ie. motor oil & gear oil) in these terms. The SAE weight system has a very broad and vague viscosity range and does not even cover the viscosity range that most quality motorcycle suspension systems require. Another point of confusion is that motor oils and gear oils are rated for viscosity on the SAE scale at different temperatures, leading to similar viscosity oils having very different ratings. [http://www.sae.org/servlets/productDetail?PROD_TYP=STD&PROD_CD=J300_200405 SAE J300] is used to define engine oils, while [http://www.sae.org/technical/standards/J306_200506 SAE J306] is used to define drive line (gear) and chassis lubricants.

{| border="1" cellspacing="0" cellpadding="5" align="center"
! SAE Motor Oil Grade
! cSt @100C
|-
| 0W
| -3.8
|-
| 5W
| 3.8 - 4.1
|-
| 10W
| 4.1 - 5.6
|-
| 15W
| -5.6
|-
| ##W-20
| 9.3 - 12.5
|-
| ##W-40
| 12.5 - 16.3
|-
| ##W-50
| 16.3 - 21.9
|-
| ##W-60
| 21.9 - 26.1
|}

 

{| border="1" cellspacing="0" cellpadding="5" align="center"
! SAE Gear Oil Grade
! cSt @100C
|-
| 70W
| 4.1+
|-
| 75W
| 4.1+
|-
| 80W
| 7+
|-
| 85W
| 11+
|-
| 90W
| 13.5 - 24.5
|-
| 140W
| 24.0 - 41
|-
| 250W
| 41+
|}

==Saybolt Universal Second (SUS)==

Some oils are labeled on the SUS / VI (ie. 85/150) or Saybolt Universal Second / Viscosity Index. Although this is slightly better system than using SAE 'weights', the Saybolt Universal Second is considered antiquated, is vague and is not a valid viscosity reference. [http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D88.htm?L+mystore+rybr7060 ASTM D88-94(1999)].

A rough conversion table from SUS grades is HERE. A very, very rough conversion table from SAE gear and motor oil grades is HERE.

<blockquote>[[Image:Cst-sus at 100C.gif]]</blockquote>

[http://www.pvdwiki.com/images/4/45/Shell-SUS-to-ISO.pdf Conversion from SUS to ISO] Courtesy of Shell. (Assumes VI of 95)

==Viscosity Index==
The Viscosity Index is very important in a suspension oil. “The viscosity index (V.I.) of an oil is a number that indicates the effect of temperature changes on the viscosity of the oil. A low V.I. signifies a relatively large change of viscosity with changes of temperature. In other words, the oil becomes extremely thin at high temperatures and extremely thick at low temperatures. On the other hand, a high V.I. signifies relatively little change in viscosity over a wide temperature range.” So specifically with regard to suspension, the greater the VI, the more consistent the damping will be over a large temp change.

ASTM D2270-04 Standard Practice for Calculating Viscosity Index From Kinematic Viscosity at 40 and 100°C

<blockquote>The Viscosity Index is calculated as such: 

[[Image:Vi-math.gif]] 

As Microsoft Excel sees it: 
VI = 100+(10^(LN((EXP(1.0727+0.6175*LN(cSt@100)+0.9744*(LN(cSt@100)^2)+(-0.3764)*(LN(cSt@100)^3)+0.04824*(LN(cSt@100)^4)))/cSt@40)/LN(cSt@100))-1)/0.00715

</blockquote>

On a lovely Sunday morning, the ambient temperature may be 21C (70F). Motorcycle forks will run in the 26C (78F) temp range, rear shocks will run in the 65C (150F) range and rear reservoirs will be around 43C (110F). While motorcycle rear shocks require very high VIs (over 300) to function well over such a huge temperature range, motorcycle forks and bicycles do not. Anything over 100VI will be serviceable for them.

==Synthetic, Mineral, and additives==

Some suspension oils are synthetic vs. mineral. These are very high quality oils and most general service applications do not require their use. You should, however, consider synthetic oil for performance applications. My Penske rear shock does require a full synthetic oil. Most oils on the market are either full mineral oil or a blend of mineral and synthetic oils. Almost all suspension oils will contain viscosity modifiers, seal conditioners, and anti-foam agents.
==Generalities==
Most cartridge type forks use a viscosity of 16 cSt@40C. (Except for Ohlins R&T, 19 cSt@40)
Most damper rod type forks are specd for a viscosity of 34 cSt@40C. (Basically ATF Fluid) although most setups require far thicker for adequate performance.

Ohlins Steering damper use 16 cSt @40C for street and 19 cSt@40C for enduro and MX

Ohlins Shocks get set up with Öhlins Shock Absorber Fluid No. 309 (#01306-01) (13.7 cSt@40)
Penske Shocks get set up with Silkolene Pro RSF (5wt) (26.7 cSt@40)

==Comercial Brands and their properties==

The oil in a bike's fork or shock not only cools and lubricates the system, but is the heart of all the damping control available for the springs. All phases of the damping involve the viscosity of the oil used in the system. Oil is such a critical suspension tuning decision that is the first priority to get worked out after spring/sag choice. No matter what all of your friends say about what the greatest high speed valves are or wild shim stacks, you should agonize over oil choice. In general, Use the least viscous oil possible that produces good slow speed damping performance with the damping adjustment screws out 1 full turn from full closed. This ensures that a fair amount of fine tuning will be available for track and weather conditions.

I suggest using either [http://www.silkolene.com/ Silkolene Pro RSF] ([http://www.pvdwiki.com/images/a/aa/Silkolene_Pro_RSF.pdf PDS])(ester) or [http://www.redlineoil.com/ Red Line] ([http://www.redlineoil.com/pdf/10.pdf PDS])(polyol ester) synthetic suspension oils for front and rear suspension systems. They both have very high VI numbers and have enough of a viscosity selection to produce any mix you may need. You should, however, stay with one brand whichever way you go. I have decided to use Red Line exclusively. They range from extremely thin to extremely thick, in five different viscosities. They make the oil in nearby Benicia, CA and the oils come in really pretty colors.

 

Viscosity, ASTM D445 (cSt) & ASTM D2270 (VI)
{| border="1" cellspacing="0" cellpadding="5" align="center"
! Brand
! cSt @ 40C
! cSt @ 100C
! VI
|-
|Red Line (Like Water!, Clear)
| 5.50
| 2.30
| 344.00
|-
|Red Line (Extra Light, Blue)
| 9.80
| 4.00
| 402.00
|-
|Silkolene Pro RSF (2.5wt)
| 13.60
| 5.83
| 464.00
|-
|Red Line (Light, Yellow)
| 18.40
| 7.10
| 407.00
|-
|Silkolene Pro RSF (5wt)
| 26.70
| 9.46
| 372.00
|-
|Red Line (Medium, Red)
| 30.40
| 10.80
| 369.00
|-
|Silkolene Pro RSF (7.5wt)
| 37.00
| 12.00
| 322.00
|-
|Silkolene Pro RSF (10wt)
| 47.36
| 13.69
| 303.00
|-
|Red Line (Heavy)
| 66.80
| 16.00
| 256.00
|-
|Silkolene Pro RSF (15wt)
| 92.95
| 19.50
| 235.00
|}

Suspension fluid must be changed often for optimum performance. Rear shock oil suffers from thermal breakdown due to the extreme temperatures that they operate in and shear forces under high load (hydrocracking). The fork does not suffer from this but does suffer from massive amounts of contamination from inside and outside.One more very important point must be made when talking about oil tuning. While tires may take around 10 minutes to reach their full running temperature, the rear shock on a motorcycle can take upwards of 30 minutes to fully heat up. This being the case, you should not attempt to change any settings in the suspension or make any decisions on which direction to go with oil viscosity until the bike has been ridden hard for at least 30 minutes.

[[Image:PVD-ISO-Viscosity-Data.gif]]

==Mixing Suspension Fluids==

Suspension fluids can be mixed my targeting a specific kinematic viscosity at a specific temperature. Since the componenent fluids maintain a fairly straight line change in viscosity as temperature changes, a ratio mix can be devised.

These two charts were prepared for Red Line and Silkolene oils:

[http://www.pvdwiki.com/images/7/7f/Red_Line_Mix_Chart.pdf Red-Line-mix.pdf] 
[http://www.pvdwiki.com/images/c/c3/Silkolene_Mix_Chart.pdf Silkolene-mix.pdf]

Or you can go to Jay Lee's (jayz28 @ MTBR.com) website for a web based calculator. http://www.provire.com/index.php/mtb

==Bicycle Fluids==
===Rock Shox===
Rock Shocks OE fluid was Torco. They have since changed to [http://www.maximausa.com/products/suspension/forkfluid.asp Maxima 85-150] Fork Fluid for damping on most forks. 15.9 cSt.

Totem uses Maxima 235-150 for lubrication and 2.5 wt (?) for damping.

===Fox===
*025-03-004-A Fox Suspension Fluid 32 oz bottle 7wt.
*025-02-003 Fox Suspension Fluid 32 oz bottle 10wt.

===Marzocchi===
Stock oil is Spectro.
Rumours of Silkolene causing problems in Marzocchi forks exist. Be careful using this mix.

Marzocchi Oil- Marzocchi Bomber Factory Fork Oil comes stock in all bomber forks. It is synthetic and is labeled as being 7.5wt. While this oil can be ordered in the US, Marzocchi is basically repackaging Golden Spectro Cartridge Fork Fluid (125/150, Very Light). This oil is rated at 26.1 cSt@40C/5.25 cSt@100C/VI 150. A very similar oil to this is Maxima Racing Fork Fluid (125/150, 7wt). It would be preferred to run a mix of Red Line Synthetic Fork Oil of 37% Red Line (Light, Yellow) & 63% Red Line (Medium, Red). In the past I have found Marzocchi forks to work far better with a thicker oil in them.

===Answer/Manitou Oil===
Manitou forks use, for lubrication, Motorex Semi-Bath Fork Oil, 5W40 from Motorex of Switzerland. This is actually Motorex Motor Oil Power Synt 4T SAE 5W40, a synthetic motor oil. This oil is rated at 90.9 cSt@40C/14.6 cSt@100C/VI 169. This is some serious pancake syrup. This oil is not widely available, but can be ordered at most motorcycle dealers through K&L Supply Co. (PN# 35-3911). Similar oils do not really exist as suspension oils. Closest is Red Line (Heavy) (66.8 cSt@40C/16 cSt@100C/VI 256) or Maxima Bicycle Fork Fluid (20wt) or Maxima Fork Oil (20wt) both of which are rated at 65 cSt@40C/12.9 cSt@100C/VI 201. If you can get access to Red Line Synthetic Motor Oil 5W40, it is rated at 94 cSt@40C/15.1 cSt@100C/VI 170 and is probably your closest bet.

==External Links==

[http://en.wikipedia.org/wiki/Viscosity Wikipedia - Viscosity] 
[http://en.wikipedia.org/wiki/Viscosity_index Wikipedia - Viscosity Index] 
 
[http://www.sae.org The Society of Automotive Engineers (SAE)]

[[Category:Bicycle]]
[[Category:Suspension (Bicycle)]]
[[Category:Motorcycle]]
[[Category:Suspension (Motorcycle)]]

Bicycle Fitting and Sizing

2011-01-03T17:53:25Z

Pvd: /* Stem Length */

==Why Fit==

==Different Philosophies==

==Serotta==
[http://www.serotta.com/fit/index.html Serotta] has been a leader in bicycle fit for quite a while. The established the [http://www.serottacyclinginstitute.com/ Serrotta Cycling Institute] to further the goals of a better understanding of bike fit.

==Fit Bikes==
* [http://www.purelycustom.com/p-315-sicipurely-custom-size-cycle.aspx Purely Custom/SICI]
* [http://www.calfeedesign.com/sizer.htm Calfee Sizer Cycle]
* [http://fitmaster.net/site/ Waterford Fitmaster]
* Serotta Fit Bike
* San Giorgio Fig Jig
* [http://www.tiemeyercycles.com/positioncycle.html Tiemeyer Cycles Position Cycle]
===My fit bike===

I got myself one of the Calfee/Mikkelson Sizer Cycles. Fun!!! I also have a PowerTAP rear wheel for it to measure power gains in different postitions.

[[Image:Calfee-sizer-cycle-1.jpg]] 
[[Image:Calfee-sizer-cycle-2.jpg]] 
[[Image:Calfee-sizer-cycle-3.jpg]] 
[[Image:Calfee-sizer-cycle-4.jpg]] 
[[Image:Calfee-sizer-cycle-5.jpg]] 
[[Image:Calfee-sizer-cycle-6.jpg]] 

==Goniometers==
http://en.wikipedia.org/wiki/Goniometer

A goniometer is used to measure the angle of the knee as well as other joints on the body when doing a fit. The goniometers that are sold throught medical channels are just too short to get good results. You need between 18" and 24". I have found a couple of very good alternatives.

Quint Measuring Systems, Inc. P.O. Box 280, San Ramon, CA 94583 (800)745-5045 http://www.quintmeasuring.com/
*24" True Angle Tool - Contractor Grade (Heavy-Duty)
*18" True Angle Tool
*4" Attachable Dial
*7" Attachable Dial

I got the 24" version because it is more rugged and thicker.

==Kits==
*[http://www.retul.com/ Retul], 3D computer anylisis
*[http://bikefitkit.com/ Fit Kit]
*[http://www.bikefitting.com/English/Frame.aspx Bikefitting.com]
*[http://www.bikefit.com/ Bike Fit Systems]
*[http://www.billbostoncycles.com/ Accufit] by Bill Boston

==Local Fitters==

*[http://norcalcycling.com/stores/fitting.shtml NorCal Cycling] in Santa Rosa. $75. They do a pretty good job. Much better than the average bike shop in the bay area. This is where I send most people that need a basic fitting.
*[http://www.wholeathlete.com/biomechanics.htm#cycling Whole Athelete], San Anselmo, CA, $220-295
*Craig Upton of [http://www.performancelabshc.com/pages.php?id=53 Performance Lab HC] , $150
*[http://www.pkcycling.com/Site/Welcome_to_PK_Cycling.html PK Racing], in Fairfax. $450-500. Primarily pro road/tri experts. They are very expensive and I have no personal experience with them other than the fact that they are only 3 blocks from my house.
*[http://www.cyclesportsonline.com/services/index.htm Cycle Sport], in Oakland. $125
*[http://www.ariavelo.com/HTML/services.html AriaVelo], in Santa Rosa.
*[http://www.hypercat.com/bike_fit.html HyperCat Racing], SF

or search Serotta by [http://www.serottacyclinginstitute.com/zipSearch.html zip code]

==Links==
*[http://www2.bsn.de/Cycling/ergobike.html Ergo Bike] Competition Bicycle Size/ Proportions Analysis By Edward C. Zimmermann
*[http://www.jacksbikes.com/index1.html Jack's Bikes] - A fit kit walk through
*[http://www.cyclemetrics.com/pages/FitLinks/bike_fit_links.htm Cyclemetrics] link page
*[http://www.roadcyclinguk.com/news/article/mps/uan/1558 Pruitt]
*[http://www.cyclefitcentre.com/further%20reading.htm Steve Hogg]

A cool poster from Ritchey Logic: http://ritcheylogic.com/media/File/5022_FIT_LOGIC_POSTER_090909lowres.pdf

==Some Traditional Numbers==
===Weight Distribution===
:Road:
*In drops decending: 45% Front / 55% Rear
*On tops climbing: 40% Front / 60% Rear
*On hoods, out of saddle, sprinting: 50% Front / 50% Rear

:MTB:
For trail I prefer a setup that sets the rider as far back as possible while maintaining control on steepest climb without too much fussing.

Fox racing shox recomends 55% for X-Country, 65% for Freeride, and 70% for Downhill.

When designing a frame from scratch, wheel offset from BB along wheelbase can be used as a ballpark start.
*Road - 58.5%F/41.5%R
*Trailbike - 61%F/39%R
*MTB Race 60%F/40%R.

===Cleat Position===

"5. Make sure that the ball of your foot [centre of the first metatarsal joint] is in front of the pedal axle with the crank arm forward and horizontal. For a rough guide for shoe size metric 36 - 38, 7mm in front; 39 - 41, 8mm in front; 42 - 43, 9mm in front; 44 -45, 10mm in front. It is unlikely that your feet are bigger than that. Don't forget to move the right cleat further back again as outlined in point 3. I know that this is at variance with the commonly given advice but you will find as you try it that it works."

http://www.cyclefitcentre.com/pdf%20final%20docs/SHOE%20AND%20PEDAL%20ARTICLE%208_final.pdf

http://www.cyclingnews.com/fitness/?id=2004/letters07-26#Cleat

http://www.cyclingnews.com/fitness/?id=2004/letters10-11#Ball

===Crank Length===

39.5% of femur length.

:L(mm) = 2.16% x I(mm)
:http://www.polaris.net/palmk/crankset.html
:"As a matter of fact, a large, persistent drop in cadence is usually a good indication that the crank is, in fact, too long."

:2.10% for taller riders

Popular Guides
Height Inseam Cranklength
:under than 5' <=70 cm. 165
:5' to 5'2" <=74 cm. 167.5
:5'2" to 5'7" <=80 cm. 170
:5'7" to 6' <=86 cm. 172.5
:6' to 6'5" <=93 cm. 175
:taller than 6'5" <=99 cm. 177.5 - 180.0

Traditional Recomendations
Height Inseam Cranklength
:under 5'7" 74 to 80 cm. 170
:5'7" to 6' 81 to 86 cm. 172.5
:Over 6' longer than 87 cm 175

http://www2.bsn.de/Cycling/cranks.html

18.5% from top of femur to floor.

Inseam:
*< 29 inches - 165 mm crank
*29 - 32 inches - 170 mm crank
*32 - 34 inches - 172.5 mm crank
*> 34 inches - 175 mm crank

Frame Size:
*54 cm or less, 170 mm
*55 - 58 cm, 172.5 mm
*59 cm or greater, 175 mm

*Gonzalez and Hull, Bivariate optimization of pedaling rate and crank arm length. Journal of biomechanics 1988, vol. 21, no10, pp. 839-849

*Danny Too; Gerald E. Landwer, The effect of pedal crank arm length on joint angle and power production in upright cycle ergometry. Journal of Sports Sciences, Volume 18, Issue 3 March 2000 , pages 153 - 161

===Knee Angle===
30-35 Degrees. More bend conserves more energy, less bend for more power.

31-32 is optimum.

===Saddle Height===
*Inseam (with cycling shoes) x 0.883 = Top of the saddle to the center of the bottom bracket. (beware oversized feet using this)
*Inseam (with cycling shoes) x 1.09 = Pedal spindle to top of saddle with pedal parallel to seat tube.

*LeMond Method - Adjust the saddle to a distance equal to your PBH* x .883, measured from the top of saddle to the center of the bottom-bracket
*Petersen Method - Adjust the saddle to a distance equal to your PBH x .873, measured from the top of saddle to the center of the bottom-bracket
*Hamley Method - Adjust the saddle to a distance equal to your PBH x 1.09, measured from the top of saddle to the pedaling surface (with the crank at bottom-dead-center inline with the seat tube)
*Holmes Method - Adjust the saddle so your knee is bent 25-35 degrees with the ball of your foot on the pedal (with the crank at bottom-dead-center inline with the seat tube)

===Trunk Angle===
About 30-40 degrees from level. (45 at most)
===Shoulder Angle===
90-100 degrees.
===Elbow Bend===
15 degrees
===Stem Length===
*Shoulder angle 90 degrees +/- 5 degrees.
*When in drops, axle obscured by bars.
*With arms bent 15 degrees in drops, plumb line from nose bisects stem at bars.

===Handlebar Height===
*1-2 inches below the saddle for small riders
*up to 4 inches for taller riders.

[[category:Bicycle]]
[[category:Frame Building]]

2011 PVD Mercury MTB

2010-12-25T18:36:17Z

Pvd: /* Print */

A much needed update of the PVD trailbike.

==The Name==

NASA Mercury Space Program. Sick!
==Tubes==

* Down Tube - TBD, 35mm x 7/4/7
* Top Tube - TBD 28 X 7/4/7
* Seat Tube - Nova CMST 460, External Butt Seat Tube, 28.6/30.0 X 460
* Seat Stay - True Temper HOXRCXSS 16mm - 10mm X 0.61mm, Single Taper
* Chain Stays - Nova CXCS-OVST-425,30/16 oval x 0.8/0.6
* Bottom Bracket - PVD Hollowtech II Shell, aSym MTB, 92mm wide x 1.75" Ø
* Dropouts - IF/PVD IS Disk
* Hose Braze-ons - Pacenti Hydro
* FDDM Braze on - PVD
* Head Tube - PVD ZS44/ZS49
* ISCG Tab - PVD

==Print==
[[Image:2011-PVD-Mercury.gif]]

==Paint==

Wine Red
RAL #3005
http://allral.com/view.php?id=3005
==Rendering==

==Parts Spec==
*Front Brake Shimano Saint
*Front Rotor: Shimano XTR, 170mm
*Rear Brake: Shimano Saint
*Rear Rotor: Shimano XTR, 140mm
*Brake Hose: Shimano SM-BH80
*Brake Hose End Cover: Shimano Y8H203000
*Shifter Set: Shimano XTR, SL-M980
*Shift Cable: Shimano Dura-ace, 1.2mm, Y60098900
*Shift Cable Ends: Cane Creek, Silver, 1.5mm
*Shift Housing: Shimano SP-41, 4mm
*Shift Housing End Caps: Shimano Sealed, Y6AM98080
*Crank: SRAM X9 39/26
*Bottom Bracket: SRAM GPX Press Fit
*Pedals: XTR Trail, PD-985
*Front Derailleur: XTR Double DM, FD-M986-D
*Cassette: XT 11-34 10spd, CS-M771-10 (BJ)
*Rear Derailleur: XT GS, RD-773
*Chain: Shimano XT 10spd, CN-HG94
*Front Hub: DT Swiss 240s Centerlock, 32 hole, QR15
*Front Rim: Mavic 819 Tubeless
*Front Spokes: DT Swiss 1.8/1.6/1.8
*Front Spoke Lacing: 3 Cross D, 3 Cross ND, Disc lace.
*Front Nipples: DT Swiss 1.8mm x 12mm Alloy
*Front Skewer: Fox/Shimano QR15
*Rear Hub: Shimano XTR, 32 hole
*Rear Rim: Mavic 819 Tubeless
*Rear Spokes: DT Swiss 1.8/1.6/1.8
*Rear Spoke Lacing: 3 Cross D, 3 Cross ND, Disc lace.
*Rear Nipples: DT Swiss 1.8mm x 12mm Alloy
*Rear Skewer: Shimano Dura-Ace
*Front Tire: Kenda Nevegal 2.1 UST
*Rear Tire: Michilin Mountain X'treme 2.2 DH
*Head Set: Cane Creek Angleset ZS44-ZS49/30, 0.50 Degree
*Grips: ODI Rouge Lock-on
*Seatpost: Easton EC90, 0mm offset, 400mm, 27.2
*Seatpost Clamp: Cro-mag 30mm QR
*Saddle: WTB Silverado Ti, 274mm
*Stay Wrap: Fizik Microtex Black w/ 0.028" Wire
*Stem: Profile Aris 100mm x 25 Degree
*Fork: Fox Vanilla 32 140mm QR15

==Weight==
*Frame - 4 lbs. 2 oz.

*Complete bike - 27 lbs. 5 oz. (12.32kg)

==Pictures==

[[category:Bicycle]]
[[category:Frame Building]]

2010-11-17T18:20:20Z

Pvd:

2008 Suzuki GSX-R750

2010-11-17T18:02:08Z

2010-11-17T17:58:03Z

Pvd:

File:CIMG0781.jpg

2010-11-17T17:57:22Z

Pvd: