Eccentric bb

[belgiangoth]

I have a bike with vertical dropouts that I would like to run fixed. Options are magic gear, eccentric hub or eccentric bb. I was wondering whether eccentric bbs are the standard size or whether they are oversized to allow the movement.

[meic]

You have standard size BB cartridge not central inside a larger aluminium cylinder which goes in a much larger non standard BB shell on a frame made specifically for eccentric BBs.

[Redvee]

Not cheap but a solution is http://www.trickstuff.de/en/products/exzentriker_KL.php

Fits in a standard 1.37" threaded BB shell and gives you some adjustment though you might need a 1/2 link

[Tiberius]

Not cheap but a solution is http://www.trickstuff.de/en/products/exzentriker_KL.php

Fits in a standard 1.37" threaded BB shell and gives you some adjustment though you might need a 1/2 link

Similar.....https://www.philwood.com/products/bbpag ... entric.php

[belgiangoth]

As I thought, at the prices involved I might as well get a new bike.

[Threevok]

Why not just run a chain tensioner in place of your rear mech ?

[Brucey]

As I thought, at the prices involved I might as well get a new bike.

not necessary! Nor is an expensive BB!

A variation on the magic gear scheme is to

a) file your VDOs (and/or hub axle ends) so that you have about 1/8" of hub movement available. This will allow adjustment for 1/4" of chain length variation. Also,

b) buy two chainrings that are just 1T different. This will allow for another 1/4" chain length variation and finally

c) use a half-link (to give 1/2" chain length variation)

Using this scheme you can have any chain length you like. I suggest setting up initially so that you have a 'magic gear' that uses the wheel fully forwards with a new chain. You can then move the wheel, use the +1T chainring, add/remove half links etc as required as the chain wears.

hth

cheers

[belgiangoth]

Why not just run a chain tensioner in place of your rear mech ?

Won't work for fixed

[Threevok]

Why not just run a chain tensioner in place of your rear mech ?

Won't work for fixed

What's wrong with single speed ? Why does it have to be fixed ?

At least with a single speed and tensioner, ratios are easily changed, to suit conditions.

[belgiangoth]

I mostly ride fixed gear, for about 10 years now. I got a very nice audax bike, steel, campag, etc, but can't get on with the gears. If I got a new bike it would be like that bike but fixed gear so I thought I would look into the possibility of making it fixed.
Single speed is not like riding fixed, it feels just as wrong as gears, just without the choice,

[Brucey]

I forgot to mention before; White Bros 'Eno' hub ought to sort you out.

cheers

[andrew_s]

Be aware that Eno hubs use a proprietary splined fitting for the sprocket.
These cost more, but the main problem is that the few UK sellers may not have the size you want in stock when you want it.

[Brucey]

it looks like you ought to get two uses out of it?

cheers

[catsnapper]

Hi Belgiangoth,

I have a low use Canadian made Forward Components EBB that works with many 68mm bottom bracket shells. It works with cranksets (Shimano) that are compatible with Hollowtech II bottom brackets. It's similar to the Exzentriker unit, well made, solid and quite easy to adjust although you might need a half link with it.

Like you I'm a long term fixed wheel user, but I now have a frame with a built in Phil EBB. As the original unit is now unused it's available at a low price.

PM me if you're interested, I can send you a copy of the original spec and instructions.

Catsnapper