108 or 113mm BB axl...
 

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[Closed] 108 or 113mm BB axle?

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Hi,

Trying to make some spanerring in spare time and looks like I have enough parts to put together commuter/bimbler bike.

Nothing fancy, just bike.

Found at the bottom of parts drawers FSA PowerDrive cranks that originally took 68x108 bottom bracket. That was supposed to be for 130mm rear spacing frame.

Frame I'll try to put it in will be 135mm spacing.

Check my logic. If it is +5mm spacing, should I add 5mmto BB axle length as well?

I don't have original bottom bracket anymore so can't just check if it fits. Need to buy new bottom bracket and just debating with myself what axle length would be the most suitable.

2x9 setup, 135mm rear spacing.

Cheers!
I.


 
Posted : 11/07/2021 7:35 pm
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Yeah, I'd go 113mm


 
Posted : 11/07/2021 7:38 pm
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Cheers!
I.


 
Posted : 11/07/2021 10:51 pm
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No, stick to the 108 otherwise the front mech won't have enough throw to get it in the big ring.


 
Posted : 11/07/2021 10:54 pm
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What mech and shifters are you planning on using?

113mm was the "norm" for these with 108 and 118 also being available. True, it's possible that the front mech might not be able to swing out far enough, but the other risk is that the chain line will be such that the chain may catch the next largest sprocket in certain gear combinations.


 
Posted : 11/07/2021 11:15 pm
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I have various front mechs kicking around. 9 speed Sora, 10 speed Tiagra, 10 speed CX70, probably even some 10 speed triple 105. Need to have rummage.
It will be paired with vintage 7700 STIs that I bought years and years ago on the whim...

If the worse coms to the worst I'll but both 108 and 113. I would rather not, to minimize cost and base myself on held parts only, but sometimes must is a must.

Cheers!
I.


 
Posted : 12/07/2021 9:11 am
Posts: 943
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I'd go 108.

The +5mm thing isn't the important bit. You want a chainline that suits the cranks, and if that is designed for 108 then stay 108.


 
Posted : 12/07/2021 11:44 am

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