Wrong bottom bracket axle length? Or something else?

[Pottsy]

It's not an area of the bike I've much experience fettling and I've come across an issue.

I'm converting a geared road bike to fixed, it was a normal compact double with an external cup bearing bottom bracket. Standard English threaded.

I've bought a square taper ISO bottom bracket (as recommended with the chain set), 111mm, and fitted it ok. However fitting the cranks today, the drive side went on ok (though the chainring is close to the chain stays) but when I fitted the non-drive crank it's touching the chain stays before it's even tightened up.

Have I just got too short an axle? Have I fitted something incorrectly? I see there are bottom brackets for triples up to 115.5mm which should give me a couple of mm more either side. However on a standard set-up previously I wasn't expecting to have to get some that long/different.

Or is there something I can do with spacers? Or have I just missed something?

This bottom bracket compatibility and chain line stuff is seemingly a bit of a black art

Thanks in advance for any assistance.

 

[RecordAceFromNew]

This bottom bracket compatibility and chain line stuff is seemingly a bit of a black art

It can be . As a matter of interest what is the chainset make and model code, what chainline are your shooting for, and what chainline are you getting? I am not saying it is your problem, but using a JIS chainset with an ISO tapered BB will give you around 4.5mm less frame clearance... Oh incidentally what frame is it (e.g. is it a mtb/hybrid frame for 135mm rear wheels, is the seat tube oversized)?

It is definitely not ideal, but a temporary quick and dirty solution is to wrap one or two layers of kitchen tin foil carefully on the left square taper as shim to give you a little clearance.

 

[Pottsy]

It's a Campag Record Pista chainset and bottom bracket.

I haven't measured anything to aim for a chain line really, I've got some flexibility at the back so I was just going to fit this part first.

It's definitely all compatible ISO stuff.

Road frame with standard 130mm rear spacing, no oversize seat tube.

Cheers.

 

[RecordAceFromNew]

It's a Campag Record Pista chainset and bottom bracket.

Are they both of the same vintage / current?

Also Campag 111mm BBs come in two sorts, symmetric and asymmetric.

 

[Pottsy]

Both current.

I have a feeling it's asymmetric, which sounds wrong immediately as I type it.

Do you reckon that's it then? I need to get a symmetric one? Makes sense.

 

[Pottsy]

I could get this one in 111mm or 115mm? Next question is measuring chainline I guess.

http://www.wiggle.co.uk/tifosi-campagnolo-fit-bottom-bracket/

Thanks for the help so far

 

[RecordAceFromNew]

Strange. According to the horse's mouth the current (and indeed recent year) Record track chainset does need a 111mm asymmetric bb. However there are quite a few ads around like this that says it is symmetric. If I were you I would examine carefully the spec of the parts and the chainline, get some clarity before ordering (especially ordering non-OEM parts).