Evening all.

I want to put an Octalink chainset onto my old Soul. The existing BB is 73mm, and I need a 68mm which I’m about to buy. Not sure which axle length I need to go for. Is it 113mm or 118mm?

Thanks!

Anyone? 😳

The axle length is dependent on the chainset, not the BB shell width. Use the same axle length as before. 🙂

…………and a couple of spacers if you want to use the 73mm b/b. Depends if you think you will notice the left crank being 5mm out.

The existing BB is 73mm, and I need a 68mm which I’m about to buy

Am I missing something here? If it’s 73mm, then get a 73mm BB. Just about to get one for my Hemlock albeit square taper…I’ll be going for 73mm x 118mm. IIRC chainring clearance is minimal on a Soul and going for a 113mm could leave it pretty tight clearance wise

i run a 113 on mine, it Is tight! no room for chain suck thats for sure, will put the chain onto the chainstay, but on 113 in middle ring still get the chain lightly touching the front mech at either extreme, would imagine would be a lil worse in the big cogs on the back!

Wallop,

If the bike needs a 68mm BB and you have a 73mm, you can fit it and have an apparent driveside axle length 2.5mm shorter giving a smaller (nearer to centreline) chainline.
If as is mentioned above, the bike needs a generous 115 or 118mm with the correct BB shell, then you will have chainring-frame clearance.
Try it and see.

i am positive its 118 for octalink

I used a 107 sq taper bb when I first put my Soul together but I found it made the crank tap the chainstay under load. I now use a 113. But that’s as much down to the crank profile as anything.

Surely if the BB shell width is 68mm you need a 68mm BB (AFAIK all Octalink BBs are fixed width – no spacers). I’ve got Octalink BBs in my bikes and 118mm with give a 50mm chainline with most Shimano cranksets, there were some old LX models that needed 121mm axles I think.

Wallop hasn’t explained herself particularly well, so just to clarify: The chainset & octalink BB are off my bike (a Genesis Altitude), which has a 73mm bb shell. The soul, being pre-2007, has a 68mm bb shell. Obviously the existing BB won’t fit on her bike, so she needs to buy another one. We weren’t sure whether to go for 113mm or 118mm axle length, but it seems from above that in order to avoid chainsuck, she needs to go for a 118mm. Thanks for the collective help!

Wallop hasn’t explained herself particularly well

I blame you entirely.

Sorry – had a few beers last night. All cleared up now though – thanks all!

I don’t think you need a new BB. Just use 2 spacers from an external bearing BB (1 for each side) and that will shim out the existing BB for the 68mm shell. Your local bike shop will have 100’s of them kicking about if you don’t.

in order to avoid chainsuck, she needs to go for a 118mm

– is spot on in my experience. I’d be a bit wary of sacrificing 2.5mm of thread engagement by using a spacer.

I don’t think you need a new BB. Just use 2 spacers from an external bearing BB (1 for each side) and that will shim out the existing BB for the 68mm shell. Your local bike shop will have 100’s of them kicking about if you don’t.

The existing BB is only a 113mm axle, so not only would it need spacers, it’d also be prone to chainsuck. For the sake of £13 to CRC I’ll probably get her a new one 😉

Wallop,

Resurrecting a oldish one here – I have a 68 x 113 Octalink BB you can try if you’re still without bracket. I’m moving the other way and I’m looking for a 73 x 113 – is yours going spare?

Cheers

Craig

I’ll reply on her behalf as she’s at a conference in that London this week. We’ve already bought a 68mm BB (118mm axle) and finished the bike:

cotic by ronnie101, on Flickr
Total cost: £195. Bargain!

Anyway, the 73 x 113 is going spare. I’ve no use for it, nor am I likely to, so if you cover the cost of postage it’s all yours. Send me an email (in my profile) & we can sort out the details.

Many thanks Rondo101, nice Cotic.

YGM.

Craig

Craig – it’s on its way. Postage was much less than I expected at only £1.80, so if you promise to pop at least that much into a mountain rescue donation tin, we’ll call it all square.

Many thanks, I will make a donation today, would have cost me at least £10 for BB so I’ll happily donate to such a good cause.