Need help from the bike gurus

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2005-12-28 4:45 PM

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Master
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Subject: Need help from the bike gurus

I'm looking at putting a compact crank on my 2005 Felt S32. Bike Nashbar has a compact crank that I'm considering, but it says that you have to have a 68x108 mm isis bottom bracket. I know that the S32 has an isis bracket, but I can not for the life of me figure out what size it is. Anyone have any ideas? 



2005-12-28 4:49 PM
in reply to: #312686

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Pro
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Subject: RE: Need help from the bike gurus

I ordered the same crank from them last year. Give them a call and the customer service person can tell you what size bracket to order OR call your LBS and ask them. I love having it on my bike, well worth the money.

2005-12-29 6:42 AM
in reply to: #312686

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Master
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Subject: RE: Need help from the bike gurus

So can I assume that new crank = new bottom bracket?

Glad to hear some confirmation that getting the compact is a good move. Thanks!

2005-12-29 8:21 AM
in reply to: #312898

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Cycling Guru
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Subject: RE: Need help from the bike gurus
"68" is the width of the bottom bracket shell and "108" is the length of the spindle. Each crank combination usually requires a different sized BB to make sure the offset is correct so that your chainrings align properly with the derailleur for shifting (and to avoid undue chain stress by having it misaligned).

Almost all road and tri bikes that are not Italian frames will be a 68 shell. You almost never see 72 on road bikes, only on mountain. 70 is Italian thread (not only is it in between the two sizes, but the threading for the cups is different. Leave it to the Italians to do their own thing ).

One thing you will need to be careful of and make sure it will work is the ability to move your front derailleur mount up and down. If you have a clamp on f.d. then it is no big deal, but if you have a braze on (a little tab attached to the frame that your f.d. is bolted to) then you may not be able to run a compact without some shifting issues.
2005-12-29 9:20 AM
in reply to: #312686

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Giver
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Subject: RE: Need help from the bike gurus
According to Felt's specs, your bike has an Isis BB, so the crank should be compatible as is.
2005-12-29 9:25 AM
in reply to: #312686

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Master
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Subject: RE: Need help from the bike gurus
Thanks for the input guys - maybe I'll go ahead and order up the crank and try it out with the existing BB.

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