Steel vs. Aluminum Driven Sprocket:
Rear wheel sprockets come in two choices of materials, steel or aluminum. Steel sprockets come stock on bikes and are very strong and last for a very long time. The performance minded rider usually swaps these out for hard anodized aluminum sprockets. By switching to a hard anodized aluminum sprocket, the un sprung weight of the rear end is significantly reduced as well as the rotating weight that the engine drives. A quality aluminum sprocket will have no safety risks associated with their use, but will wear out far quicker than their steel counterparts. If the overall goal of your motorcycle is to ride it hard for a long time, put minimal money into it, and have it work reasonably well, then a steel sprocket should be your choice. If maximum performance of the suspension and acceleration is more important than shorter part life, then the lighter aluminum sprocket should be your choice.
Somewhere between the steel vs. aluminum decision is the Stealth Sprocket. These are fairly nice steel sprockets that are mounted to an aluminum carrier. This keeps the weight down, and the wear low. These sprockets are still heavier than the aluminum sprockets and cost quite a bit more. It is my opinion that it is probably better to use the extra money spent on this setup toward a second setup once the first wears out. This gets into religious arguments, so everyone will have to find their place on this.
520 Conversions :
Many racers and performance riders will mention doing a 520 chain conversion. Most stock bikes come with 525, 530, or 535 chains on them. These are big chains that can handle the power of a modern sport bike and make chain life acceptable for most riders. A 520 chain is much smaller than their counterparts. a 520 chain is much lighter reducing the un sprung weight of the rear end and reducing rotational mass. The life of a 520 chain will be much less than the larger chains as well. While this is a performance improvement, the average rider will benefit more by saving their money and switching the gears that they can while keeping whatever good chain is on the bike in place. If you need to change your chain anyway, then go for it, the cost is not much different that standard parts. A 520 conversion is not recommended on bikes larger than 750cc's.
The DID 520 chains are listed below. The DID 520VM should be chosen for street riding and the DID ERV2 should be used for racing.
| Model | Plate Thickness | Wear Index | Tensile Strength | Weight (lbs) | |
| Inner | Outer | 100 Links | |||
| 520VL | 0.087 | 0.087 | 2430 | 8100 | 3.88 |
| 520VM | 0.079 | 0.079 | 3140 | 8050 | 3.39 |
| 520ERV2 | 0.079 | 0.079 | 2820 | 8180 | 3.53 |
Motorcycle chains follow ISO 10190 and JIS JCAS 12 specifications for tolerances and specifications. US Tsubaki describes motorcycle chains HERE. A quick reference to chain dimensions is HERE. HERE is another nice article on chains.
How to clean and lube your chain:
1. Get a plastic spray bottle from the local hardware store.
2. Fill the bottle with kerosene
3. Spray kerosene on chain as you spin the wheel, aim at the rollers.
4. Spin the wheel for a few minutes to work the kerosene into the rollers. (remember with o-ring chains, you are only concerned about the rollers)
5. Take a clean dry rag and rub down the chain until clean. chain should shine!!
6. Spray a quality chain lube (NOT WD-40) on the inside of the chain, specifically the edges of the rollers, as you spin the wheel. I like Silkolene 100% synthetic race lube.
7. Spin the wheel for a few minutes to work the lube into the rollers.
8. Take another clean rag and spray kerosene directly onto it, getting it moist.
9. Rub down outside of chain and over spray area to remove the excess chain lube. (Remember, it's all about the rollers, the outside only needs a protective film for rust prevention).
10. Once chain has been properly cleaned and lubed, after every ride or two, wipe the outside of the chain with the kerosene rag, lube, then wipe down again with the kerosene rag. Its easier when you stay on top of it.
11. IMPORTANT: THE EDGES OF THE ROLLERS SHOULD ALWAYS APPEAR WET FROM LUBE, IF YOUR CHAIN LOOKS DRY, YOUR CHAIN IS NOT PROPERLY LUBRICATED.
When is a Chain Worn Out:
A drive chain is considered to be worn out once it has elongated by 1.5% of it's pitch length. Certainly, for performance riding, a chain should be replaced once the chain has elongated by over 1%, and certainly by 1.5% for any use. 20 links of a 5## series chain (0.625" pitch) will measure 12.500" pin to pin (on center) when new. It should be replaced when the chain is measured at 12.625"(1%) or 12.688"(1.5%) pin to pin. It may be considered fine to swap sprockets around while the chain is within 0.5% elongation or 12.5625" in this example. See an article on this HERE and HERE. On source of disagreement with all this is Diamond Chain Co. which says that a chain is worn when it has elongated by 3%. This means that the chain in this example would have elongated 0.375" over the 20 links. This seems a little excessive. In another section of their FAQ, they even suggest 1.5% elongation. (D.I.D. - HERE)
| Drive Chain Length (41 pins / 40 links) | UNIT: mm (in) |
||
CHAIN SIZE CODE |
PITCH |
STANDARD |
SERVICE LIMIT |
415/420/428 |
12.70 (0.500) |
508 (20.0) |
511 (20.1) <518 (20.4)> |
520/525/50 |
15.875 (0.625) |
635 (25.0) |
638 (25.1) <648 (25.5)> |
630 |
19.05 (0.750) |
762 (30.0) |
766 (30.2) <777 (30.6)> |
< >: Without o-ring chain |
|||
Sprocket Size and Squat:
Sprocket selection does not just effect the final drive ratio. Sprockets effect the path that power takes to the rear wheel. As the position of the upper chain line changes with respect to the swing arm pivot, so does the tendency for the bike to squat or jack. If only the front sprocket is reduced in size, the rear of the bike will get more anti-squat. If only the rear sprocket is increased in size, the rear of the bike will get more anti-squat. If both are changed, some geometry would have to be done to figure out what the final outcome would be. This is a very subtle change, nothing that will ruin a ride, but is a component in the full understanding of gear selection.
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