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PostPosted: Sat May 04, 2013 5:30 am 
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I've got a race face ti bottom bracket and it feels quite flexy. It only flexes noticeably when I'm out of the saddle cranking up hills and sprinting. Is this a common trait of Ti bottom brackets?

If so what would be a good stiffer replacement?


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PostPosted: Sat May 04, 2013 6:57 am 
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Could be, I never notice any though.

Replacement, the steel version... A complete HT2 setup?


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PostPosted: Sat May 04, 2013 7:59 am 
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Never heard of a B/B flexing :?
Crank arms or B/B shell area of the frame yes.

What frame is it and what model is your chain set?
One other thing what weight are you? (That's not meant to be insulting BTW).


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PostPosted: Sat May 04, 2013 8:20 am 
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The frame could be adding to the perceived flex as well. I have the bottom bracket installed in a Bianchi Ti frame. In terms of weight, I'm a 170 pounds plus or minus 5.

The tubes on the frame are huge, and the ride is quite a bit stiffer than I remember my previous King Kikapu being. I was hoping that this would rule out the frame being the cause. I plan on using this bike as my pavement trainer so it'll hopefully getting some throttle quite often.

I guess my concern aside from flex would be durability. Will the bottom bracket spindle be able to handle a noticeable amount of flex without breaking? More importantly, should I be concerned?


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PostPosted: Sat May 04, 2013 8:34 am 
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eshew wrote:
I guess my concern aside from flex would be durability. Will the bottom bracket spindle be able to handle a noticeable amount of flex without breaking? More importantly, should I be concerned?


I thought one of the qualities of Ti was its resistance to fatigue, at least it better be Ive got a Ti tourer :wink:

Im approx 182lbs .......


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PostPosted: Sat May 04, 2013 8:40 am 
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You ain't that heavy, over sized frame tubes mmmmmmm :?
Whats the chain set/cranks your using?


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PostPosted: Sat May 04, 2013 8:45 am 
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The cranks are race face next lp's with RF rings. Running wide platform pedals.


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PostPosted: Sat May 04, 2013 8:57 am 
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Aaaa I think its your cranks, if Ive got the design correct aren't those the ones that are kinda square in section and narrow as they hit the B/B shaft, IMHO there's not enough strength at
that end of the crank arms. (Do you have a photo of the chain set?)


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PostPosted: Sat May 04, 2013 9:22 am 
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Ti is a funny thing. About a 3rd lighter than a typical steel, but not as stiff so you need to use more material to achieve the same rigidity, which brings components back into the weight range of steel ones. Requires clever design an construction techniques to being any real benefit.


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PostPosted: Sat May 04, 2013 9:29 am 
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Correct, which is the main reason Ti forks are few and far between :?


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