Veloce crankset on Shimano BB with Shimano 600 front mech??

keef66 Posts: 13,123
edited April 2011 in Workshop
Doing up an 80s steel Peugeot which my son acquired for 4 cans of Guinness. Front mech doesn't seem to want to move far enough to get the chain onto the big ring. Downtube shifters (new) so it's not an indexing problem, and it's the same if I detach the cable anyway. Both limit screws are backed out all the way.

Crankset* is Campag Veloce double with a 53 big ring, but it's mounted on a Shimano UN52 square taper BB; don't know the axle length, wishing I'd read the label when it was out of the frame.

My theory is that it's the BB that's at fault, meaning the chainrings are too far out for a double front mech. There's supporting evidence in that there's a lot of unused inboard adjustment, and there's certainly enough chainstay and bb shell clearance for the whole thing to come inwards 10mm at least.

I measured the gap between the seat tube and the big ring at 40mm, which is the same as on my bike, But mine's a triple with a fatter alloy seat tube, so I don't know if that's a useful comparison.

(* just the drive side; the LH crank is some hideous, badly matched angular alloy lump)


  • pete.whelan
    pete.whelan Posts: 788
    Campag chainsets sitting on a Shimano BB will be a few mm further out than if a Campag BB was used of the same length (Have a look on Sheldon Brown website).

    Either a Campag compatible or a shorter UN52 will work
    Recipe: shave legs sparingly, rub in embrocation and drizzle with freshly squeezed baby oil.
  • keef66
    keef66 Posts: 13,123
    Thanks for that, you've helped confirm my suspicions. I've now spent most of the morning browsing Sheldon's words of wisdom and various forums, and I'm now a world expert on the subject. The whole thing needs shifting inboard by at least 10mm to give it the standard road double 43.5mm chainline.

    The shortest Shimano BBs I can find are 110mm spindle length. Which will probably be OK if the BB already in there is a lot longer. CRC have one for £6 !
    Failing that, as you say, I need a campag fit 111mm BB which is going to set me back £20, and possibly need a different tool to fit it.

    I'm wishing I'd done the research before reassembling the bike. Everything is legible, so I knew I had a Campag crank and a Shimano BB, so why did I not realise the potential problem? Really regretting not making a note of the BB spindle length while I had the thing sitting on the bench.
  • floosy
    floosy Posts: 270
    Have a look at Miche bottom brackets they are ISO std and can get them in 107mm or if you look around to can get campag ones (also ISO std) down to 103mm