Originally Posted by
shaneshane
Yup, whether 11-36 or 11-42, the smallest cog are both 11, though the chain length should be different due to the largest cogs are different. so when two bikes that one with 11-36 and one with 11-42, and both shift to the 11 gear (smallest cog). the derailleur actually should work for both situation but with different chain length.
That was my point, and that means if I increase the chain length slightly on my bike (11-36), it should be fine, make sense?
Sure. You are not going to hurt anything by putting on a chain that is 1 to 3 links longer than the one you have.
I’m not an expert on clutched RDs, so I’m just going with the SRAM recommendations for Force 1.
You are correct: if you switched from your 11-36 cassette to a 11-42 cassette, SRAM would tell you to size the chain quite a bit longer, even though the smallest number of total teeth you have (42+11=53) is the same with either cassette.
With standard RDs on regular road bikes, there have long been two options for sizing the chain:
1. Make it just long enough to go big-big.
2. Make it as long as it will go, making sure it’s not too long in small-small.
For #2, you size the chain by putting the bike in small-small, with the chain wrapped through the RD, and you shorten the chain just enough so that the chain doesn’t drag on the front jockey wheel of the RD.
I don’t know if that approach is appropriate for a clutched RD – hence the SRAM manual’s instructions to size the chain with a version of #1.