juan replied to the topic A Shim 10 spd MTB cassette work ok with Shim 10 spd road mech? in the forum Bike Forum 3 weeks ago
Ok I have been running a 11/42 10 speed MTB cassette on the hardtail with a 9 speed rapid rise rear mech and a flatbar tiagra 10 speed shifter (first gen).
Back in the days 9 speed MTB and 10 speed road had the same cable ratio.
To make it work though I had to use a pilo mech hanger to lower the mech