Eccentric BB - why?

[pete75]

Building a hub gear specific frame with an EBB seems an expensive way of dealing with chain adjustment. For many years hub geared bikes had horizontal dropouts - cheap, simple and effective chain adjustment.

[Mike Sales]

Because with vertical dropouts an eccentric avoids the need for chain tension adjustment when replacing the wheel?

[rareposter]

You don't need to re-tension the chain every time you remove the wheel.
The position and setting of the rear brake never changes.
The wheel is always straight in the frame and can't pull over.
Wheelbase stays constant (although admittedly that is so minor in the grand scheme of things, a couple of mm at most, that virtually no-one would even notice)!

[pete75]

You don't need to re-tension the chain every time you remove the wheel.
The position and setting of the rear brake never changes.
The wheel is always straight in the frame and can't pull over.
Wheelbase stays constant (although admittedly that is so minor in the grand scheme of things, a couple of mm at most, that virtually no-one would even notice)!

1. Something that's quick and simple to do and may not even be needed with some designs of horizontal dropouts.
2. Is this ever a problem?
3. Never had a wheel pull over and if it's set straight to start with it will remain so.
4. Does this matter?

[MartinC]

You don't need to re-tension the chain every time you remove the wheel.
The position and setting of the rear brake never changes.
The wheel is always straight in the frame and can't pull over.
Wheelbase stays constant (although admittedly that is so minor in the grand scheme of things, a couple of mm at most, that virtually no-one would even notice)!

1. Something that's quick and simple to do and may not even be needed with some designs of horizontal dropouts.
2. Is this ever a problem?
3. Never had a wheel pull over and if it's set straight to start with it will remain so.
4. Does this matter?

1. Not quick or simple to do in the dark and lashing rain after a puncture.
2. Yes it is 'cos the rim/shoe interface can change significantly.
3. I've had wheels pull over. I'd like to think it's the enormous power of my legs but........
4. We all agree on not much but it may affect your mudguard clearance.

Given the choice of EBB, Horizontal Drop Outs or a chain tensioner I don't know which is best, and I've used all 3.

[pete75]

You don't need to re-tension the chain every time you remove the wheel.
The position and setting of the rear brake never changes.
The wheel is always straight in the frame and can't pull over.
Wheelbase stays constant (although admittedly that is so minor in the grand scheme of things, a couple of mm at most, that virtually no-one would even notice)!

1. Something that's quick and simple to do and may not even be needed with some designs of horizontal dropouts.
2. Is this ever a problem?
3. Never had a wheel pull over and if it's set straight to start with it will remain so.
4. Does this matter?

1. Not quick or simple to do in the dark and lashing rain after a puncture.
2. Yes it is 'cos the rim/shoe interface can change significantly.
3. I've had wheels pull over. I'd like to think it's the enormous power of my legs but........
4. We all agree on not much but it may affect your mudguard clearance.

Given the choice of EBB, Horizontal Drop Outs or a chain tensioner I don't know which is best, and I've used all 3.

1 It's done by feel. Anyhow repairing a puncture in the dark is more involved than putting the wheel back in. How does rain make the job more difficult? Back in the Sturmey Archer days we generally mended the puncture without taking the wheel out though.
2. Not my experience, except with rod brakes. They need the rod length adjusting. Not that many bikes use rod brakes now though.
3. Who are you kidding. Merkx used bikes with horizontal Campag dropouts and if his wheel didn't pull over yours ain't going to.
4. Not really because you fit the mudguards to allow for adjustment.

[tenbikes]

If using disc brakes then the brake mount also needs to slide. Many drop outs in modern frames have this feature.

I'd rather have an eccentric BB.

[mjr]

3. Who are you kidding. Merkx used bikes with horizontal Campag dropouts and if his wheel didn't pull over yours ain't going to.

I'm guessing Mr Merckx had a mechanic torquing his nuts well every time and replacements readily available if any bike developed problems. I've had wheels pull over a few times in my frame with sloping dropouts: most seriously when I came to an abrupt stop after hitting a tree!

I've had all three and I think I prefer an EBB then sloping dropouts then tugs. Not yet tried a tensioner wheel.

[scottg]

You can also use a ghost cog.

[foxyrider]

3. Who are you kidding. Merkx used bikes with horizontal Campag dropouts and if his wheel didn't pull over yours ain't going to.

His wheel didn't pull over because the horizontal drop outs had setting screws which ensured a straight fit every time - and of course a properly closed Campag Q/R is more secure than hand torqued nuts!

[Jupestar]

You don't need to re-tension the chain every time you remove the wheel.

I did find a way to do this quite well with rear drop outs. Planet X tensioners, which if you took the track nuts off could also slide off without adjusting, meant when you put them back in the wheel was in exactly the same place.

The position and setting of the rear brake never changes.

As above, otherwise yes it's v.annoying.

The wheel is always straight in the frame and can't pull over.

Again clever use of the tensioners can reduce this, but wheel pulling over is a frame not a small issue for me. Obviously it happens when grinding up a hill, I have very high max power. (EBBs are also not faultless in this regard).

We all agree on not much but it may affect your mudguard clearance

Yep. It's doesn't take much.

I prefer EBBs

The sort of forward sliding drop outs typically on older conversions are discounted for me, can imagine the wheel being dragged out the drop out. No thanks..

Rear track style drop outs, as well as all the above comments. It's just much harder/slower to get the wheel out. If you find a solution, (Planet Xs chain tensioners help, or no tensioners if you are ok with that) then it's ok. but only works on single rear cog and no RD.

Surly (for example) do there rear horizontal dropouts also with a derailleur hanger/bolt, You can also get hangers designed to fit horizontal rear drop outs. In this set up getting a wheel with a cassette off the rear with the RD is just an horrible experience, with many grazed knuckles. EBB in all cases make the wheel just fall out.

EBBs are not faultless though. Adjusting a EBB shell can mean taking the BB out, which can also mean crank arms off. EBBs do get stuck they need regular grease. And they can slip/squeak.

I always look for an EBB frame, ideally one which can take a RD hanger so it can ride it SS, IGH or Cassette.

I'd I was just riding a simple fixie with 120 dropouts it wouldn't matter, doubt you'd find a EBB in that frame anyway.

[pete75]

3. Who are you kidding. Merkx used bikes with horizontal Campag dropouts and if his wheel didn't pull over yours ain't going to.

His wheel didn't pull over because the horizontal drop outs had setting screws which ensured a straight fit every time - and of course a properly closed Campag Q/R is more secure than hand torqued nuts!

Yes - what's wrong with using quality horizontal drop outs - all the horizontal drop outs on my bikes have setting screws.. How else do you expect stuff to be torqued if not by hand - you've got a foot opertaed torque wrench maybe?

[pete75]

3. Who are you kidding. Merkx used bikes with horizontal Campag dropouts and if his wheel didn't pull over yours ain't going to.

I'm guessing Mr Merckx had a mechanic torquing his nuts well every time and replacements readily available if any bike developed problems. I've had wheels pull over a few times in my frame with sloping dropouts: most seriously when I came to an abrupt stop after hitting a tree!

I've had all three and I think I prefer an EBB then sloping dropouts then tugs. Not yet tried a tensioner wheel.

You don't need a pro mechanic to set up wheel nuts/qr though. I've never had a wheel pull over - not to say I won't though. The other day, after 50 odd years of repairing punctures, I actually manage to puncture an inner tube when refitting a tyre. First time ever, front tyre on a BMW R90S motorbike. I suppose gradual incompetence is part of ageing.

[cycle tramp]

Building a hub gear specific frame with an EBB seems an expensive way of dealing with chain adjustment. For many years hub geared bikes had horizontal dropouts - cheap, simple and effective chain adjustment.

That's fine. You don't have to buy a bike with an EBB if you don't want to. However for those of us who have such frames, appreciate them.

[cycle tramp]

3. Never had a wheel pull over and if it's set straight to start with it will remain so.

3. I've had wheels pull over. I'd like to think it's the enormous power of my legs but........

Given the choice of EBB, Horizontal Drop Outs or a chain tensioner I don't know which is best, and I've used all 3.

3. Who are you kidding. Merkx used bikes with horizontal Campag dropouts and if his wheel didn't pull over yours ain't going to.

In regards to 3, my brother's fixed wheel with horizontal dropouts suffered with this issue - the wheel could be persuaded to pull over side when climbing. As a result he fitted a chain tug to that side - the very fact that chain tugs exist demonstrate that its somewhat of a known issue..