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Old 07-29-04, 06:36 AM
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Join Date: Nov 2003
Location: Kanata, Ontario, Canada
Posts: 80

Bikes: Stevens SLC Road, Seven Ti SS MTB, Titus Ti FS-XC MTB, Empella Bonfire CX

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Originally Posted by jfmckenna
can you explaine the eccentric BB thing? I did a quick google search and it's late now but basically what it looked like to me is that the whole rear triangle is on a sliding scale bracket type thing attached to the BB. Is that the case? here is the pics I found:
Sure, here's a pic which should explain everything.

Essentially, a standard BB threads into an expanding wedge. This wedge is allowed to rotate within an oversized BB shell. The standard BB is offset from the center of the eccentric, so when the eccentric is rotated, the BB actually moves fore/aft and up/down in the shell. This allows for chain tensioning at the BB instead of at the rear dropouts.

I simply loosen the EBB with a 4mm allen key and then rotate the unit with a Park spanner until the desired chain tension is achieved. Tighten. That's it. No fiddling with trying to align a rear wheel in horizontal drops, no fidding with a rear brake, etc. Very simple...and, effective. I've been racing on my Seven SS MTB for over 4-yrs and my EBB has never creaked, slipped, etc. That's why I had Seven use it again on my SS 'cross.

There are 3 types of EBBs:
1 - expanding wedge (Bushnell);
2 - pinch bolt; and
3 - set-screw.

Oh, and here's a recent pic of my 'cross bike. I used my 'cross bike as my solo 24 Hr back-up bike. Fortunately, I suffered no mechanicals, etc. on my primary 24 Hr race bike, so I never needed it. But, it was ready-to-go.

Ride Hard,
Mike B.
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