Derailer(Chain Length) Alignment Question *Please Help*
11-04-04, 11:09 AM
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Derailer(Chain Length) Alignment Question *Please Help*
Okay so i just bought a new shimano derailer. Okay I measured the chain on the largest of the two chainrings but not throgh the derailer. So I trimmed the chain and put on the adjustable link and ran it through the derailer now my instructions show that when its going through the derailer on the smallest back chainring in the back and the largest chainrings on the front then the rear cassette and the two pulleys on the rear derailer will line up in a straight line through the centers. And this is susposed to make a right angle at the floor. Now mine isn't doing this
On mine the first pulley is a inch right of the cassette center and the 2nd pulley is two inches right of the cassette center. Now my question is my chain must be to short right? But why would this be I measured it 3 times to make sure I can't see how this could be the problem.
Any kind of advice/assistance would be greatly appreciated
Thanks
Brian
On mine the first pulley is a inch right of the cassette center and the 2nd pulley is two inches right of the cassette center. Now my question is my chain must be to short right? But why would this be I measured it 3 times to make sure I can't see how this could be the problem.
Any kind of advice/assistance would be greatly appreciated
Thanks
Brian
11-04-04, 11:50 AM
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What happens if you shift into the big/big combination? If you can shift into the big/big and the derailleur cage still has a little bit of give in it, then your chain isn't too short for the gears you are using today.
There are several different ways of determining chain length and they tend to produce slightly different chain lengths. Using the big/big sizing method, like you did, produces the shortest chain that will safely cover that gear combination. That gives you the lightest chain and the best spring tension on the derailleur cage. The only drawback that I can see is that, if you change to a larger cassette, you'll also have to add some length to your chain.
There are several different ways of determining chain length and they tend to produce slightly different chain lengths. Using the big/big sizing method, like you did, produces the shortest chain that will safely cover that gear combination. That gives you the lightest chain and the best spring tension on the derailleur cage. The only drawback that I can see is that, if you change to a larger cassette, you'll also have to add some length to your chain.
