Thursday, August 19, 2010

Cranks and BB's

Found another fried ISIS bottom bracket in the SS......they hardly last a year. sigh.
I also get a chuckle our of the fact that buying a complete crank set with BB only costs 50 dollars more than just buying the BB.
I am also surprised at just how little has been developed as far as cranks getting lighter. I really do think that the lightest setup you can get is a Middleburn with a WI square taper bb. So I guess my question is whether or not outboard bearing bb's are truly stiffer (measured as deflection) than other crank interfaces (octalink, JIS, ISIS,) What about Hollergram (how my TN friends speak of Cannondale technology)?

I can speak to the fact that 15G cranks from the Hive are pretty stinking stiff and still lighter than cranks costing twice as much. They shift good too. Not Shimano good, but good non-the-less.

Is one brand of external bearing bb longer lasting than another?

It kind of makes me wonder what the weight differences between SLX, XT, and XTR is, once you remove the chainrings?

just ruminations.



have you tried ceramic bearings in your BB, supposed to last 5 times longer and only cost thrice as much.....

Shad S. said...

You may also try popping the bearings out of your outboard bb and replacing them for $3 a piece from your local hardware store. I pop the seals out and over pack them with grease and they're good to go for longer than the friggin bike ones last!

Joshua Stamper said...

Yeah, the only problem is that my outboard bearing last for quite a while. I have only ever had to replace one outbaord BB, and that was on the gravel road bike. Rather its the ISIS bearings that suck.

Neve_r_est said...

Outboard bearing quality must have been improved since they were first introduced. The XTR outboards that came on my Scalpel and the Race Face Duece outboards were crap, went through four or five in a two year span. It was like they didn't have seals at all.

I've been through the ISIS deal too, hence all my bikes now have Phil Ti bbs and Middleburn cranks.

I think crank flex is a marketing hoax. The only set of cranks I've ever felt flex were my Tune Bigfoots(RIP junk).