I’ve got an eccentric BB on my Cannondale Trail SL. Not a clue how to use it and now have a slack chain. Amy tips how to adjust things?

I can only tell you what I do with the one on my Swift.

1. Slacken the bolts under the bottom bracket.
2. Put a big 8mm(?) hex key into the hole in the side of the EBB.
3. Heave on the hex key, levering against the cranks to rotate in the desired direction (for extra credit put something soft between hex key and cranks).

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4. Remember to re-tighten the bolts under the bottom bracket *before* you go for a ride!

EDIT: try to clean out the bolt heads before undoing so you don’t round them off.

Some have bolts under the BB on the outside, as oldnpastit describes.
Some use an internal wedge.
If there’s no bolts visible outside, look for a single hex key head on the end of the BB.

As mentioned above, there is a wedge which holds it in, on one side will be some hex bolts loosen them and it should slide out. Adjust then tighten.

I think there maybe a cover over the wedge

Mmmmm, ebb, looks like so much of a better solution than track ends! 🙂

http://simplyseanie.blogspot.co.uk/2013/05/cannondale-trail-sl-29er-3-ss-eccentric.html

I think you can fit a bushnell in the Cannondale BB shell if you want an easier to use insert. Adjusting a bushnell is a 4mm allen key, 30-second trail-side job.

After loosening the bolts, it’s sometimes useful to give the whole thing a tap with a rubber mallet to relieve any binding.

Shermer, the ebb on a swift is wonderfully simple & effective. Just make sure the shell/bolts are greased and tensioning is a 30 second job.

There’s a pdf with diagrams on the Cannondale website. That’s the best place to start.

Had one, undo the little allen key, note it won’t fully come out, then you need to tap to release the wedge, then adjust, the very small allen key on the other side is there to stop it being shoved the whole way through the frame. Found adding plumbers mate the green stuff from b&q stopped it slipping and losing the chain tension.

Thank for that, the PDF says I need a pin spanner tool, can I bodge round this?

In the past I’ve used a Cannondale wedge type (on a tandem) and a Carver Bushnell copy. The Cannondale wedge was better in terms of not slipping, not filling up with muck and not rounding the allen bolt hex hole (and Cannondale also used a standard cap head bolt if it ever needed replacing).

You can sometimes rotate the loosened eccentric for tensioning using the crank arm as a lever – Find a long screwdriver or allen key that fits in the peg hole or bottom bracket splines. Hold it parallel to the bb axle and rotate the crank until it jams against the screwdriver shaft. Lean on the screwdriver and continue to rotate the crank and it should turn everything together (if that makes any sense!)

Mine had a hex hole for taking an allen key to turn it to tighten it, might be worth checking yours isn’t like that, 5mm allen key if my fading memory serves me.