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?
Originally Posted by
fronesis
If you switch from the 11-36 cassette on there now to an 11-42, you will definitely have to replace the chain.
According to the SRAM manual for Force 1, chain length is set strictly by the size of the front chainring and the largest rear cog, so a properly sized chain for a 42 chainring and 36 cog will NOT be the right length for a 42 - 42.
And it's not just that it wouldn't shift well: I highly doubt that the current chain would even wrap around the 42 cog, so you could do serious damage to your RD and hanger if you put on an 11-42 cassette and tried to shift into the lowest cog with your current chain.