Another slipping gear thread

Ok I have a genesis Tarn 10 MTB I bought 2nd hand. It's always been a little sticky shifting - sometimes have to shift down 2 gears to go back up 1 etc. but I just lived with it assuming the cable needed replacing. Occasionally gears slipped under pressure in small sprockets eg out of the saddle but have always assumed this was part of the same issue.

So replaced the inner and outer shift cable and have put a new 10spd chain on - gave the mech a good clean and lubed any pivot points.

Despite spending 30 minutes trying to index it it is still not quite right and the gears now slip more.

So I can stick a new cassette on it and try that - see if the slippage us new chain on old cassette but that wouldn't explain the sticky shifting?

At this point I check on the internet to see what original cassette they came with and I think (it's a blue and black Tarn 10 single front ring) they came as 11 speed - but this one has a 10 speed cassette 11-42 and a SL M610 trigger shifter which Google says is 10 speed.

I'm thinking previous owner may have downgraded it to 10 speed at some point - but possibly left an 11 speed mech on. Would this explain the shifting issues?

I can't find any identification marks on the mech - other than Shimano which doesn't help much - will they be there somewhere and would an 11 speed mech not be quite right with 10 speed shifting?
[Castle Donington Ladies FC - going up in '22]


  • Have you checked the rear derailleur hanger alignment?

    I'm not up to speed on my compatibility of 10 / 11 speed shifters!
  • No I haven't - it did cross my mind the other evening so yes could be that.
    [Castle Donington Ladies FC - going up in '22]
  • Anyone know if an 11 speed mech or I suppose 11 speed chainring with a 10 speed cassette, chain and shifter might cause these issues ?

    Or how to identify if the mech is 10 or 11 speed?
    [Castle Donington Ladies FC - going up in '22]
  • whyamihere
    whyamihere Posts: 7,708
    Shimano MTB 10 and 11 speed derailleurs are actually compatible. They sell a Deore level mech which is advertised as 10/11 speed (, and I've previously run an 11 speed XT mech on a 10 speed system. The chainring would be fine as well.

    It does sound like a bent hanger might be the culprit, it's worth checking that before anything else.
  • Thank you. Think I'll buy the tool then.
    [Castle Donington Ladies FC - going up in '22]