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Staggering sober
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Discussion Starter · #1 ·
I'm modifying a tandem cruiser to include an EBB. Which does your bike have, do you like it, and why or why not?

Thanks

Tim
 

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Derailleurless
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I have two.

The Cannondale's is a bit of a pain in the butt. It's a wedge-type EBB that requires a lot of anti-seize to keep free. It's stayed quiet, so once in place, not much of a problem, but knocking the wedge loose and rotating it is not a fun project.

The other is a very novel Mrazek design. It's a threaded EBB. I'm not sure this would be an option to you unless you have the capability to fully thread the inside of an oversized shell. If you're interested in details, let me know and I'll let you know more about it. Quiet, secure, and very easy & controllable to adjust.

If I had my druthers for a custom deal, I'd either duplicate Mrazek's design, or use a simple pinch-bolt EBB.
 

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Staggering sober
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Discussion Starter · #3 ·
Adjustments...

Thanks for the reply. All options are open right now. I actually have to have the American (BMX) shell cropped out of the steel frame and a new one welded in to accommodate the new BB. Where did you find this Mrazek BB, and is the shell available already threaded?

Thanks again.

Tim
 

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TwoWheelinTim said:
Thanks for the reply. All options are open right now. I actually have to have the American (BMX) shell cropped out of the steel frame and a new one welded in to accommodate the new BB. Where did you find this Mrazek BB, and is the shell available already threaded?
I didn't consider it, but you could try contacting them through www.mrazek.com (they are a frame builder in the Czech Republic) and see if they'll sell just the shell. But they do their frames in aluminum; not sure if they would do something in steel. Can't hurt to inquire.

I don't have any photos of the BB removed, but I posted pics of the frame here: http://forums.mtbr.com/showthread.php?t=373639
 

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My Tandem has 2 set-screw Phils eBBs. My single speeds have Bushnell, Phils set-screws, generic setscrew, and a full split-shell pinch bolt. I've pretty much used them all.

My preference is for Bushnell eBBs - there are several other expansion type eBBs, and I find the Bushnell's to be the best. Set screws are fine as long as your tolerances are tight, they are popular on cheaper tandems as they are simple and easy to make. I've never been happy with pinch-bolt eBBs, but they can be made to work well.

There are variations with each type, and some work better than others, but in general, they are all crap if the BB shell frame prep is not good. Any irregularities in the BB shell (ie: weld distortions) prevent the eBB insert from seating properly, and leads to creaking, regardless of type. The frame builder really makes the biggest difference.
 
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bushnell

I have a custom tandem with Bushnells front and rear, running a rohloff. Problem free, although I do pull them every 3-4 months and anti-sieze.

D
 
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