[towerscum]

Switched to a Sram Force 50/34 crank set from a FSA Gossamer cross 46/34 on my cross bike.
Repaced the 50t with a Thorne 46t.
Now,the chain rubs on the 46t when going from inner to small. Even rubs when a few cogs up from that.
Didn't happen with the FSA.
Ring spacing wouldn't be different would it?
How bout' the cup width? I wouldn't think so.
What gives?
I realize those shifts combos are not the healthiest,but I do want them.

Thanks!


Towerscum

 

[FBinNY]

Ring spacing might be marginally narrower, or the chain-line a bit more inboard because of a difference in crank offset.

Check the chain-line first, since that's most important. If necessary(and possible) re-space the BB to move the crank outboard. If that's no an option you can increase crank separation by making spacers from find grit sandpaper. They're best used between the arms and inner chainring.

 

[towerscum]

Hmmm...

Yea,crank profile. I guess I could put in a shimano outboard BB spacer.
Will try with an update.

towerscum

 

[towerscum]

clueless in Alaska

Didn't work. In fact,before it even approached the torque spec,it binded up. And it still rubbed.


towerscum

 

[ohvrolla]

Chainline would be my first guess as well since cranksets were changed. You could go to the manufacturer's website and look up both products to see if a bottom bracket is spec'd for each. I know the FSA crank I bought had the proper length spindle listed on their website for the crank I purchased.