[Closed] How to stop my eccentric bb from shifting?

Are you sure it's not just a new chain stretching/bedding in?

Chain is well worn in so it is not that. The original owner got rid as he was fed up of the bb moving about btw.

Is it set so the BB itself is in a higher/forward position? Apparently it should be. -a friend had this happen with a phil wood EBB in his bike and the excellent Mike-at-dialled suggested he check where his bb was (in relation to the whole ebb) and change it to this way round. Never slipped/creaked again after that.

When you say a 'higher/forward position' do you mean with the bb at between 1 and 3 o'clock when viewed from the right of the bike?

agree with having axle in 2 o'clock position - body weight etc will try and move it down against chain tension.

try carbon assembly paste rather than grease in the BB shell.

Also make sure there's no 'holes' in the bb shell that the bolts are slipping into after you've tightened them and shifting the bb/loosening off.

That was what I was also going to say. Then as you pedal you should have chain tension also helping it to stop from moving.

The ebb is riddled with imprints from the bolts. This had not escaped my notice but the bolts en are dished so leave a cookie cutter imprint and I would hope are less likely to drop into pre-existing holes than a plain bolt.

Lots of solutions to this kind of thing ont he Niner forum on MTBR - a layer of plumbers tape, that sort of thing.

Carbon paste strikes me as a goo idea

Oh dear. Went for a look on the nicer forums and they recommend running your ebb in a lower position, contrary to the above advice. Who ever said single speeds were simple?

On my duster I gave up with that chaep style EBB and got a Bushnell - not a cheap fix, but very much fixed 😀

I had a look at the Bushnell bbs. Better part of a hundred quid though. I'd not object to spending the money but the frame I have is basically a bit on the short side so I really just need to find a solution with the existing kit.

Have got the exact same problem with my GT Peace. Bought it second hand as a dog walking / pub bike, but need to tighten the bolts every second ride. I don't feel like spending £100 to sort it out as that would double the value of the bike 😕

Someone suggested loctite on the bolts - is that a stupid thing to do?

Advice received on a nicer forum:
a guess; strip off the crank, loosen the EBB bolts and slide the EBB out. where the bolts pinch the EBB, is the surface of the EBB damaged?

if so then one possible solution is to rotate the EBB to its secondary location (for each correct tension point below the horizontal, there will be an identical one above) hopefully it's far enough away form the damage for the bolts to bite properly. Or buy a new EBB insert

I will be trying this plus loctite on FlowerPowers's bike maybe tonight..

Get a non-set screw EBB insert if possible, the shell may well be deformed by bolt pressure. I think Bushnell make a cr-mo EBB that's cheaper than the lightweight version and it's a good design. Putting the axle in a higher/fwd position may work, but it's just a minor bodge for a slippy / creaky EBB set up rather than the way they should be in general.

I'm going to try the change in bb position to 2 o'clock in the shell. If that works, great. If it does not at least I will have had a useful proof of concept for how the notional Alfine build should be spec'ed later this year.

mtbfix - Member

Oh dear. Went for a look on the nicer forums...

...and I thought this thread was quite a nice helpful one overall... 🙁

Will the latest Niner EBB fit ?
Mine seems ok. Charlie-the-monger of bikes said to ignore the advice about plumbers tape, various pastes, greases & Peruvian mountain yack blubber; & to just leave it totally dry.

mtbfix - Member
Oh dear. Went for a look on the nicer forums...

...and I thought this thread was quite a nice helpful one overall...

Another case of the iPad doing the thinking for me and getting it wrong. And me not reading what I was about to post.