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Discussion Starter · #1 ·
About to swap out the stock crank set. My frame uses a BB86 BB, so if I go with Shimano, i can re-use the stock BB. Am thinking about a long term group swap out to SRAM. Is there any noticeable difference in spindle stiffness between SRAM and Shimano? The SRAM uses the 'stepped' GXP BB, while the Shimano uses the 'constant diameter' spindle. Thank you in advance.
 

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MTBDad said:
Is there any noticeable difference in spindle stiffness between SRAM and Shimano? The SRAM uses the 'stepped' GXP BB, while the Shimano uses the 'constant diameter' spindle. Thank you in advance.

You pretty much answered your own question. (answer in bold)

So to use the BB86 frame with a Sram crank, you will need the standard GXP crank, but have to get the correct sized bearings to be pressed into the frame.

What is your stock crank?
 

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Discussion Starter · #3 ·
Giant Defy Advanced came stock with a FSA Gossamer Triple. I'm such a rookie road biker that my question is almost certainly moot, but... I suffer from chronic up-graditis (my MTB quiver is a testament to my illness). I am likely to swap out the stock 105 group for SRAM, but not married to the notion of a perfectly matched set-up, so if Shimano is stiffer, shifts better, whatever, I'd be happy to run a Shimano crank with SRAM Shifter/Der, etc
 

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IIRC, the FSA bearings are the same as the Shimano bearings sizing wise. So all you would have to do is remove said FSA crank, install Shimano crank of your choice, then adjust the front derailluer.

The difference between Sram & Shimano as far as spindle stiffness goes, is non existent. The difference is in the chainrings/spider setup. A Sram is pretty good for shifting if its setup properly, but the new Ultegra & DA is tops for chainring stiffness and shifting.

I'd personally would go with a Shimano Ultegra crank (6700 series) and then make a choice on the rest of the components.
 

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I'm pretty sure you're right on the FSA bearings, and, yes, the SRAM ones, I belive ONE is the same, but one is different.

The 6700 crank is pretty darn good. The 7900 one is spectacular, but, is nearly the price of an entire 105 group...


frdfandc said:
IIRC, the FSA bearings are the same as the Shimano bearings sizing wise. So all you would have to do is remove said FSA crank, install Shimano crank of your choice, then adjust the front derailluer.

The difference between Sram & Shimano as far as spindle stiffness goes, is non existent. The difference is in the chainrings/spider setup. A Sram is pretty good for shifting if its setup properly, but the new Ultegra & DA is tops for chainring stiffness and shifting.

I'd personally would go with a Shimano Ultegra crank (6700 series) and then make a choice on the rest of the components.
 

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Discussion Starter · #6 ·
I was all but set on the SRAm Red, but now I'm leaning towards the D/A 7950! decisions, decisions. I guess there are far worse problems to have!!
 
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