Hello all I am looking to replace my FSA platinum pro ISIS bb. I know I have a 68mm shell but the 108/110/113 number is where I am looking for assistance. Is that number the length of the bb? Can I put a 113mm in where I currently have a 110? If I did what effect would it have?

Thanks!

The numbers "108/110/113" ie the over all length of the BB's axle . ( from one end to the other ). If you put in a 113 in the place of 110 ,it could or can throw off the chainline witch will affect shifting and the front derailer may not have the reach to reach the largest chainring .

Pop off your crankarms and measure the old one with your caliper so you know which one to get. Then get one on eBay for $10.

So the 3mm would make a big difference? I am actually in the process of perfecting the shifting in the front and thats why I was curious about the bb measurements.

I just got rid of the stock FSA chaingrings and replaced them with SRAM which has been a dream in itself. The front is now shifting smoothly but the Platinum Pro BB is getting noisy and since the BB are so cheap on eBAY I wa considering either the American Classic or Crank Brothers but only see good deals on the 113 variety.

Is there a way to tell what size my bike is made to take? though I assume it is 110 but the stock BB has long since been gone. I have been fighting the full upgrade to a GXP and trying to make the best of the ISIS setup.

Any advice would be appreciated.Thanks

ans, as stated above, the BB and crankarms go together to create the chainline; thus, your bike frame was not "made" for any specific spindle length, but rather for a chainline. ISIS is pretty much obsolete now, so you won't see much choice in ISIS BBs. You'll have to decide whether to pay up and buy a new crankset that takes a more common BB, or pay up and buy an ISIS BB of the correct length for your crankset.