Hi lads I run a 9spd long cage xt mech on my 10 spd cx bike instead of the tiagra mech. I currently have 34t cassette on do you think that mech will accommodate a 40!or 42t cassette? If not I’ll just put an MTB double chain set on. I can manage most hills with the 34 but was a bit hard after 5 days riding.
Maximum capacity will be 34t. So I think 40 will be pushing it. You might manage it with a goatlink type thing.
Put a double on seems the easiest solution unless you don't have the kit. If you're buying stuff for that, change it for a cheapy 11 speed setup.
Maximum capacity is the difference between the largest and smallest sprockets, not the size of the largest sprocket ie. how much chain the mech will wrap.
So 10:42 is 32T, - within the capacity of the mech.
That just means that the cage length will cope with that sprocket size range. The mech won’t work on that spread though as the parallelogram and jockey wheel offset is designed to work with smaller spread cassettes (combined with double or triple chainsets- hence the large capacity).
A longer b-screw or a goatlink could get it working as long as you can accept that the shift quality will be compromised.
Cheers lads . I will be buying stuff and don’t want to spend too much. The hanger extenders are only cheap on wish etc so might try one of them. I will also be buying a cassette so may work simpler to get a cheap deore chainset 😀. I know Tripple chainsets aren’t in fashion but they solved a lot of problems.
I run a 9 speed Saint rear mech in a 9 speed set up with an 11-40 cassette and a 36-26 double with no goatlink and just the regular b screw.