8sp/9sp woes. Grrrrrrr!

Discussion in 'Bicycle Mechanics and Repairs' started by Proto, 11 May 2008.

  1. Proto

    Proto Veteran

    My trusty old Vitus 992 (now a wninter/commuter bike :blush:) is still kitted out with C Record 8sp, but as old age overtakes me I've rather taken a shine to these new fangled compact chainset thingees, so thought I'd fit one to my Vitus.

    Saw a bargain clearance offer on Chainreaction a while back, Truvativ Rouleur compact, integrated BB design, 50/34, 170mm cranks - £50.00 including the bearing cups. So I bought one.

    Stripped the bike down this weekend and gave it a bit of love and attention, and fitted new chainset. Shifting is fine on cassette (13/26) and chainset.

    However there is a problem with the chain, which when on the inner chain ring, rubs/catches the outer ring. Makes bloody awful noise. It does it even when on the middleish sprockets, so indicates to me that the chain is too wide for the design of the chainset. So I need to sort this out.
    Various possibilities:
    • Spacing washer between chainrings
    • Fit a 9sp or 10sp chain
    • Upgrade to 9 or 10sp throughout
    Couple of questions for the experts out there.

    Washers. I could machine up some washers, just a bit off a faff. Anyone got any or know where I could get some.

    Narrower chain is the easy fix, current chain is a bit 'tired' anyway. But can I run a 9 or 10 sp chain in a 8sp rear mech with 8sp jockey wheels in place? Or should I fit the narrower 9 or 10 sp jockey wheels? And will a narrower chain fit on 8sp sprockets? I'm guessing inner width of chain is common to all chains, only the outer width varies, and sprocket thickness is very similar for 8/9/10 sp. Correct?

    Upgrade. Anyone got some Campag 9/10 sp kit they want to sell? F & r mechs plus ergos. Can't fit 9sp to my existing wheels, but I've already got some Mavic Ksyrium Equipes with Campag freehub waiting in the wings.

  2. Smokin Joe

    Smokin Joe Legendary Member

    There should be no problem fitting a 9 or 10 speed chain. That would be the cheapest option, as a chain is a consumable anyway.
  3. 02GF74

    02GF74 Über Member

    I would disagree. Comparing 8 and 9 speed chain, the link side plates are the same thickness so since the 9 speed is narrower, it must follow that the inner width is narrower too.

    I have never compared sprockets but would expect the 9 speed to be slightly narrower, whether this is earily spotted by eye, I don't know.

    I *think* I read that you can run 9 speed chain on an 8 speed set up but not other way round
  4. OP

    Proto Veteran

    Sprocket thickness on 8/9/10 sp is very close. According to the late great Sheldon Brown 1.90/1.75/1.70mm respectively. I measured a few of my 8sp last night and they were 1.85 - 1.90 or so. I'm going to convert a 9sp to 8sp by re-spacing to 8sp pitch (5.0mm), and leaving one out too, of course. Then I can use my Mavic wheels.

    Newest Campag ultra narrow chains are down to 5.9mm wide. (pins are flush with the side plates). KMC 9 and 10 sp chains are 6.2mm wide and 6.6mm wide respectively. The chain currently fitted to my bike (Rohloff) measures 6.85mm.
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