Proper Bottom Bracket Size????

[burler]

So I'm building up a 2003 Giant NRS1 frame and have a question about bottom brackets/cranks. I checked the OEM specs on the 2003 Giant NRS1 and saw that it came with a 68x113 bottom bracket and Race Face Prodigy crankset. SO, When I ordered my crankset (Race Face Evolve XC) and bottom bracket (FSA Platinum) I requested a 68x113 size. My problem is now that I have the crankset it says "for use with a 108mm spindle length only". Is this a problem? Will that extra 5mm length REALLY make a difference? If so, what would the problem(s) be? I can think of two possible things: 1) problems shifting in the front (but i should be able to adjust the FD to overcome that, right?), or 2) increased torque on the bottom bracket shell/frame due to the cranks being farther away from th ecenter of gravity. Please help and give me your thoughts of whether I should be concerned about this or not!!!! :help:

[BikeGeek]

I followed Race Face's advice when I upgraded my hardtail (with a 133-mm spindle) with the Evolve crankset and 108-mm spindle and have had no problems with it. It has something to do with the design of the crank-to-bb interface. I think 113-mm will give you problem 1 and chainline issues with the cassette. I don't know about problem 2.

[binary visions]

I'll bet you a dollar when you bolt it all up, you won't have a bit of shifting trouble, and certainly no torque problems. You have an extra 2.5 millimeters on either side. No way are you going to tell the difference. Hell, frame alignments are often off more than that.

[burler]

ok...well that's one-to-one now on wheter this'll be an issue or not...i was leaning towards the side of "2.5mm extra on either side not making a difference", but who knows....shifting IS a precision thing, right? i mean 1/4 turn of a limit adjuster can make a big difference....

[BikeGeek]

If the front shifting problem shows up, it's simple to fix with the barrel adjusters and limit screws. I honestly don't know if 2.5mm is enough of a chainline variance to cause rear shifting problems or not. I've mostly been single speeding lately so it's been drilled through my head that chainline is key.

[burler]

Thanx for the info and thoughts....I contacted the person i bought my build kit from and he said he's happy to send me out a 108 AND return postage for the 113 so i think I'm gonna go ahead and swap it out for what the crankset says is required....i don't think the 113 would be a problem, but since he's willing to swap 'no questions asked' I'm gonna go ahead and do it...

[Spunger]

113's are pretty normal.

Just be carefull. If you use a wide one (118) which I've seen around it will cause some funny shifting issues. Most BB's can fit 68/73 with the little spacer they include with them.

I'd swap it out though. Just make sure you tighten the drive side first, torque it to what it says, and then tighten the other side until it's tight. Put cranks on and go!