Difference between revisions of "Head Angle Change With Suspension Travel"

From Pvdwiki
Jump to: navigation, search
Line 1: Line 1:
According to some modeling that I have done, a good rule of thumb is that head angle will change on a hard tail mountain bike approximately 0.05° per mm of travel.
+
According to very accurate calculations that I have done, the head angle will change on a hard tail mountain bike approximately 0.0521° per mm of travel if it has a 1058mm initial wheelbase. The bottom bracket height will change approximately -0.3868mm with each mm of suspension travel.  
  
Bottom bracket height will change approximately 0.372mm with each mm of suspension travel. These again are very rough rules of thumb but make designing frames fairly quick.
+
Different wheelbase bikes will change at different rates.
 +
==Formulas==
 +
Here are the equations:
  
This is good to understand when designing long travel hard tails.
+
A12 = Initial Head Angle
 +
B12 = Fork Offset
 +
C12 = Sagged fork length
 +
D12 = Initial Wheelbase
 +
E12 = Initail BB Height
 +
F12 = Chainstay Length
 +
G12 = Wheel Diameter
 +
H12 = Fork Compression or extention from sagged
  
 +
==Head Angle Change==
 +
[[Image:Head-angle-change.gif]]
 +
==Bottom Bracket Height Change==
 +
[[Image:Bb-height-change.gif]]
 +
==Mechanical Trail Change==
 +
[[Image:Mechanical-trail-change.gif]]
  
 
[[category:Bicycle]]
 
[[category:Bicycle]]
 
[[category:Frame Building]]
 
[[category:Frame Building]]

Revision as of 00:45, 14 December 2007

According to very accurate calculations that I have done, the head angle will change on a hard tail mountain bike approximately 0.0521° per mm of travel if it has a 1058mm initial wheelbase. The bottom bracket height will change approximately -0.3868mm with each mm of suspension travel.

Different wheelbase bikes will change at different rates.

Formulas

Here are the equations:

A12 = Initial Head Angle B12 = Fork Offset C12 = Sagged fork length D12 = Initial Wheelbase E12 = Initail BB Height F12 = Chainstay Length G12 = Wheel Diameter H12 = Fork Compression or extention from sagged

Head Angle Change

Head-angle-change.gif

Bottom Bracket Height Change

Bb-height-change.gif

Mechanical Trail Change

Mechanical-trail-change.gif