bikeaday

Hi,
Been away from this forum for a while and need advice on a crankset change. Going from a 105 52-42-30 9s. and hopefully moving to a Tiagra 50-39-30 10s. as it is hard to find a Tiagra 9s and 105 too pricey. Can I anticipate problem with a 10 s. crank on a 9s. drive train.
Thank in advance for you advice.
André.

Tim_Iowa

No problem. A 10s Tiagra crank will cause no issues with a 9 speed drivetrain (including 9 speed chain). Go for it, the new 10s Tiagra is nice.

Problems ensue when you try to go the other direction and use a 10 speed chain on an 8 (and sometimes 9) speed crank. The 10s chain is narrower and won't engage properly with the wider chain ring. No problems using a wider 9s chain on a narrower 10s chainring.

FastJake

+1 No issues with your plan. The new HollowTech II cranks are nice stuff.

Alternatively, you could just put 50/39 rings on your 105 crank since it's the same 130mm bolt circle diameter.

bikeaday

Thanks guys. Finally after a few searches and pressure !!! from my lady friend, I (she) decided to go with a 48/36/26 9s., either a Deore or Alivio, I have a braze-on dérailleur on that frame, seems that the dérailleur will be low enough for the 48, maybe just need to file 1-2 mm at the bottom to make it go lower. One question, originally it was a 52-42-30 crank with a 105 dér. Do you see problem using the same dér. ???? with the new crank.
Thanks again.

FastJake

As long as you can get the cage low enough it should work just fine.

70sSanO

While not pertaining to 10s, the only thing I can offer is what happened to my brother when he went from a road to a triple mountain crank, I think it was a Race Face. He said that he swapped out the BB with the one that came with the crank, but he still had chainline issues. Personally I think that it is just a matter of calculating where everything should be, but he has successfully built a few bikes from the frame up, so I just gotta go with what he said. Plus he gave me the new crankset/BB and I put it our sons mountain bike so it all worked out for the best... at least from my perspective.

John

bikeaday

That was my problem, not low enough. Ended up tapping a new 5mm thread hole above the original hole to get it low enough. New crank coming in next week, crossing my finger !!!!