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Replacing a BB . . . spindle diameter question

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Replacing a BB . . . spindle diameter question

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Old 09-27-09, 01:44 PM
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Replacing a BB . . . spindle diameter question

I am replacing a 2009 Sram Force regular with a similar compact double, 50/34. I bought a Sram Force compact double with a GXP bottom bracket for a good price. I know the GXP won't work with the BB30 in my 2009 Giant tcr advanced sl but will the spindle on my new crank adapt to BB30? More specifically, is the spindle on my new crank 24mm while the spindle I'm replacing a 30mm? I also read there is an adapter that will adapt the 24mm crank to fit the BB30. I need some help. Any thoughts? Much appreciated.
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Old 09-27-09, 01:56 PM
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I'd look around for a spindle shim, don't know if you will find one tho. It's kinda a bad idea to force a part that takes so much abuse as a crank/spindle to work in a space it is not intended for, seems like you would be asking for trouble, or at least poor performance.
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Old 09-27-09, 02:00 PM
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Originally Posted by sooprvylyn
I'd look around for a spindle shim, don't know if you will find one tho. It's kinda a bad idea to force a part that takes so much abuse as a crank/spindle to work in a space it is not intended for, seems like you would be asking for trouble, or at least poor performance.
Don't guess.

The OP is looking for something called a BB30 adapter. They exist: https://www.universalcycles.com/shopp...s.php?id=29424
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Old 09-27-09, 02:11 PM
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Ok, I'd do some research on how well this adapter works before going with it. Look for some reviews of the part. Also the cost of using this piece might outweigh the cost of just getting and installing the proper BB-parts, labor and the chance of improper instalation. Part $20 shipping Probably another $7, installation at a shop maybe another $20-also it is out of stock at this site(you can probably find it wlsewhere). It might be cheaper to just get a new BB and install it yourself.

If you decide to get it put up a review of your own for the rest of us who made need a part like this. Consumer reviews are an invaluable tool for this market.
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Old 09-27-09, 02:13 PM
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Originally Posted by sooprvylyn
Ok, I'd do some research on how well this adapter works before going with it. Look for some reviews of the part. Also the cost of using this piece might outweigh the cost of just getting and installing the proper BB-parts, labor and the chance of improper instalation. Part $20 shipping Probably another $7, installation at a shop maybe another $20-also it is out of stock at this site(you can probably find it wlsewhere). It might be cheaper to just get a new BB and install it yourself.

If you decide to get it put up a review of your own for the rest of us who made need a part like this. Consumer reviews are an invaluable tool for this market.
None of these are a concern if you actually knew how much a BB30 crankset costs. I do agree, the OP should probably just get an actual bb30 crankset though.
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Old 09-27-09, 02:36 PM
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Hey, I'm not pretending to know how much every part costs, but if you are using nice parts you are using them because of thier improved performance. Why comprimise performance to jury rig a part to fit where it doesn't belong. If you are going to do this get a BB with a 24mm diameter and save the 30mm BB for later(or sell it on ebuy)
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Old 09-27-09, 02:41 PM
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Thanks for the thoughts. I'm not sure what I'm going to do. This may be a stupid question but do they make a large bb that will fit my giant tcr advanced for a 24mm axle?
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Old 09-27-09, 02:52 PM
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Originally Posted by dfoss1
Thanks for the thoughts. I'm not sure what I'm going to do. This may be a stupid question but do they make a large bb that will fit my giant tcr advanced for a 24mm axle?
Er. That should fit fine. It just uses the standard ext bottom bracket...?
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Old 09-28-09, 09:07 AM
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replacing a BB . . . spindle diameter question

Thanks for all the thoughts. I'm going to my LBS this am and we'll see if the crankset with the 24mm axle works. Here's hoping. If I go with the adapter I'll post later when I have some experience. Otherwise you'll see it on ebay. A little knowledge is a dangerous thing especially in my case.
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