[jhenry4]

i have a crankset choice to make soon and need to know the difference between a standard bottom bracket and one with outboard bearings. my assumptions are that stiffness will be increased with outboard bearings, but i would also think this would negatively effect the Q factor.

right now i'm looking at the FSA line with the ISIS megaquad topping my list of standard BB's

weight is not a primary concern here. i'm looking more for performance, durability and reliability.

thanks

 

[OnTheRivet]

i have a crankset choice to make soon and need to know the difference between a standard bottom bracket and one with outboard bearings. my assumptions are that stiffness will be increased with outboard bearings, but i would also think this would negatively effect the Q factor.

right now i'm looking at the FSA line with the ISIS megaquad topping my list of standard BB's

weight is not a primary concern here. i'm looking more for performance, durability and reliability.

thanks

I think chainline gets a little jacked as well with outboard bearings. When is somebody gonna bite the bullet and just go with a bigger diameter BB shell. That along with a 145 rear axle spacing standard would be the ticket.

 

[the bull]

I think Specialized now has a larger BB shell.

What I mean is, I saw one on a carbon frame. I think it was a Specialized.

 

[alienator]

Specialized, Cannondale, Pinarello (and Opera?) all offer bikes w/ oversized BB shells. As for outboard bearing BB's, it's like anything else. Some are good, and some aren't. Q factor doesn't necessarily increase. Dura Ace and Ultegra Q factors haven't really gone up w/ the move to outboard bearings. And as far as stiffness goes, square taper BB's were and are still stiff enough the most powerful thighs (Boonen, et al), so it's not like us mere mortals really need the extra stiffness. Maybe it gives a psychological edge.

 

[cthomas]

Agree with Alienator...

I run an FSA MegaExo on my main bike. Has the same chainline and q-factor as the "old fashioned" Octalink BB/FSA crankset it replaced. Even at 240lbs I can't tell the difference between the two, and I recently swapped them back and forth (2x on one day) when I was chasing a creaking noise. I realized as I was doing this that I had spent big $ on an "upgrade" that really didn't do anything for me.

The one thing I did like about the MegaExo was the ease of installation. Very easy to install and remove (but needs a special tool). Mine is only a few months old, so no idea how long the bearings will last.

As noted in many other threads, the biggest difference in "stiffness" in the bottom bracket has more to do with the bike than with the BB/Cranks.

 

[jhenry4]

oversized bb's

the oversized BB's on cannondale, pinarello, and now specialized are a great idea. one of my cannondale's has this BB with the hollowgram crankset and it's great...but i wish there was an industry standard for the OS BB's.

my current BB search is for a specialized roubaix for my wife's first road bike.
thanks for the feedback thus-far.

 

[Mark McM]

Outboard bearings and ankle clearance?

i have a crankset choice to make soon and need to know the difference between a standard bottom bracket and one with outboard bearings. my assumptions are that stiffness will be increased with outboard bearings, but i would also think this would negatively effect the Q factor.

As others have said, there is no reason that outboard bearing should necessarily alter Q-factor or chainline. But I wonder what affect they have on ankle clearance? I found that one of the advantages of low profile cranks was that it gave more clearance for my ankles. With "old style" cranks (like Campy Nuovo Record) which had very straight arms I found that my ankles frequently banged or rubbed against the crank arm, and often mounted my cleats to move my feet outward on the pedals to lessen this affect. With the low profile cranks, I could move my feet further inboard on the pedals, and I found I preferred this narrow stance. Do outboard bearing cranks decrease ankle clearance?