ISIS bottom bracket question

jimmer111

I have got play in my Crank brothers cobalt ISIS bottom bracket and need a replacement. I appreciate the isis system is not the most highly regarded but not in the market for new cranks too just now!

I have heard good things about the Superstar components isis bottom bracket (best of a bad bunch) and it is reasonably priced. However my current bottom bracket is 68/73 x 113mm, the frame (Cove Hustler) is a 68mm shell so i have a spacer currently on the drive side.

Superstar sell specific bottom brackets i.e. 68 x113 or 73 x 113mm, they are out of stock and not restocking my size (68x113mm) , question is can i run a 73 x 113mm with a spacer (effectively what i am doing now).

My thinking is yes but would like it confirmed please. Sorry for the ramble also

supersonic

Should be fine - but no harm in double checking with Superstar.

If you have no luck then I have an as new Truvativ ISIS BB that works with 68 or 73mm.

jimmer111

Cheers, i have dropped them an email but as yet no reply.

Thanks for the offer but not a fan of second hand bottom brackets (no offence). Just one of those parts i would always buy new.

supersonic

It is new lol! It was removed from a new bike and never used.

jimmer111

Well, Had a reply from Superstar below:

Hello the BBs aren’t designed to use spacers so I doubt that would work, it would make the axle offset from centreline.

Now, if a bottom bracket (like the one i currently have) is a 68/73 x 113 and you have a 68mm frame then the spacer takes the space up to give a certain chain line. Surely fitting a 73 x 113mm bottom bracket with a spacer (or chain device in my case) in a 68mm frame would give the same chain line as a spaced 68mm bttom bracket as the axle length is 113mm in both cases.

Please can someone help me out as my brain is frazzled!!!

jimmer111

Also worth adding i am running a double and bash ring, not a tripple.

nicklouse

jimmer111 wrote:

Surely fitting a 73 x 113mm bottom bracket with a spacer (or chain device in my case) in a 68mm frame would give the same chain line as a spaced 68mm bttom bracket as the axle length is 113mm in both cases.

Please can someone help me out as my brain is frazzled!!!

nope as it is not designed to use a spacer. the chain line will be changed.

one spacer each side then yes.

jimmer111

Thanks for the reply, please forgive my ignorance but as you have probably gathered i am struggling a little with this (much prefer diagrams)! How will spacing the non drive side bring the chainline back?

Cheers James

jimmer111

Right think i have got my head round this.

I think the problem i am having is my current bottom bracket has been installed wrong by whoever fitted it causing confusion. I currently have one spacer in my setup on the drive side but this is only 2.5mm thick. In theory there should be another 2.5mm spacer on the no drive side at the moment, correct?

Therefore if i buy a new 73mm bottom bracket to use on my set up i can install it with the stinger on the drive side and the 2.5mm on non drive side and this should give the correct chainline?

Thanks again for any input

nicklouse

so you are going for a BB mount device on a 68mm shell.

you need a 68mm E type BB then. if you are going to buy one.

and sorry i was meaning half a spacer width each side.so 2.5mm or the ND cup may not sit correctly.