bottom bracket width - campy super record cranks

I’ve got a set of super record cranks, going to run the smaller chainring (42T) with a 16T rear…

What width bottom bracket is most appropriate - 102mm or a 111mm?

thanks in advance :slight_smile:

is your cranks for track or for road?
Track - 111mm
Road - No Idea…

they’re road (double) cranks

i’ll run the inner ring only in this configuration.

cheers

what i really need is the technical drawing of the cranks, so I know the alignment of the outer chainring to the end of the axle;

eg:
axle of 102mm, gives 51mm each side of frame centre
if the outer ring sits inboard, say 5mm from the end of the axle, that gives 51-5=46mm chainline.
say nominally the inner chanring is 5mm from the outer ring, then running the inner ring will give 46-5=41mm chainline.

So does anyone know where the technical data for these campy cranks can be had?

I found this site but I don’t get it…
http://www.bicycleclassics.com/bottom.html

my cranks are attached

If your cranks are currently installed and you know the spindle length of the current BB, you’re set. If you don’t know the length, measure the chainline, then remove the cranks and measure the spindle. Easy!

Measure the chainline you have now, and then determine your spindle needs. The only thing to watch is symmetrical vs non which adds another step in the calc to adjust for the offset.

eg. if your current CL with SR cranks and a symmetric 113mm BB is 46mm on the inner and you want 42mm, then you need to drop 4mm either side = 113-8mm = 105mm. If you can’t find the right spindle length to get within 1-2mm of your target, use BB/cassette spacers and a too short spindle to increase the chainline slightly.

Worst case: Phil BB, fine tune to perfection.

FWIW, Sugino Super Mighty’s are essentially a Record copy, and you get a 42mm chainline on the outer position with a 111m AC-S BB. From memory the 115 (triple?) AC-S worked for the inner pos. Of course they may vary slightly.

Thanks Blakey.

I just bought the cranks, and don’t have a bottom bracket in the frame.

“FWIW, Sugino Super Mighty’s are essentially a Record copy, and you get a 42mm chainline on the outer position with a 111m AC-S BB. From memory the 115 (triple?) AC-S worked for the inner pos. Of course they may vary slightly.”

looks like a Phil around 116 will work - they allow around 5mm of adjustment from what i know.

anyone know how much are Phil BBs?

Ahh, sorry, when you said ‘my cranks are attached’ I thought you meant ‘to a bike’, not ‘as a jpg’.

Why do you want to use the inner ring? Aesthetically the outer looks better, unless you’re planning on doing what I did and cutting down a 52T ring for a chainguard.

Before you drop a lot of cash on a Phil (Dan @ Shifter or Lynn @ CTA), I’d buy a cheap Campy AC-S in 111 or 115mm and see what that yields. Then you’ll know exactly what Phil to buy, but the AC-S is a good BB. I have the tool to fit it (MEL) if you need it.

thanks again Blakey.

I’m going to get Dan to build the bike up so hopefully he can grab a suitabe AC-S BB for it!

cheers - you’ve been a great help :mrgreen:

You’ll probably find Dan knows what spindle length suits super mightys. Anyway, if Dan’s on the case for you, he’ll sort it out properly.