6 speed drivetrain 10 speed crank

waughie
waughie Posts: 180
edited February 2015 in Workshop
I have a late 80s early 90s Peugeot Course roadbike that I got given a few years ago without its original wheels, I bought a cheapest set of Macic Aksiums from Merlin and swapped the original useless brakes for some Tiagra ones. So the bike isn't original and I'm not that interested in making it that way...

Recently I have noticed that the drive side crank arm is twisted so that the pedal oscillates as it goes round, this has damaged my knee so it now needs to go! The bike has 6spd downtube shifters and cassette etc. I wanted to put a Tiagra 10spd crank on the bike, to get it running again. If I swap the chain to a 9spd will it run ok together?

In short, 6speed cassette, 10 speed crank, 9 speed chain. Will they be compatible?

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    You'll need to run a wider chain e.g. 8-speed or wider to make it work - narrower chain won't run on the freewheel. 8 speed chain will be cheaper and stronger too - might be a bit noisy running on the narrow chainrings though
    Make mine an Italian, with Campagnolo on the side..
  • waughie
    waughie Posts: 180
    As far as I was aware 8 -9 speed chains are pretty much the same...
  • ravey1981
    ravey1981 Posts: 1,111
    6-7-8 speed chains are all the same width. 9, 10 and 11 get progressively narrower. How did you get the 6 speed cassette onto the mavics? spacers? I have an old 6 speed bike tucked away somewhere but I'm pretty sure its of the screw on freewheel type.

    Have you looked for some period cranks on ebay?, I would think there would be a few about.
  • waughie
    waughie Posts: 180
    Yep, I used spacers to get the 6spd cassette on. Admittedly quite a few spacers but the chain line is fine and it runs smooth, also the gap down the back of the cassette means the spokes don't get destroyed if the chain does manage to come off the top.

    I was preferring the idea of something modern rather than something period purely to make replacements easier in future.
  • waughie
    waughie Posts: 180
    Basically all I need to workout is what speed chain will work with a modern 6spd cassette and a 10spd crank. That's why I was thinking a 9 as that will let me get a nicer rear mech at some point too.
  • ravey1981
    ravey1981 Posts: 1,111
    Hmm I don't know the answer to this, my gut feeling is that it wont work. The limiting factor really is the gaps between the sprockets on the cassette rather than mechs. Chainsets are generally compatible with different speed chains, I know 8,9 and 10 will work together fine for example. I'd try an 8 speed chain if I were you.

    It all comes down to which bits you eventually want to keep I suppose.
  • Semantik
    Semantik Posts: 537
    waughie wrote:
    Basically all I need to workout is what speed chain will work with a modern 6spd cassette and a 10spd crank. That's why I was thinking a 9 as that will let me get a nicer rear mech at some point too.

    Never seen a 6 speed cassette , unless it's an old Uniglide one. They were screw on freewheels back then I'm sure.

    No matter. The cheapest and best way is to get a 7, 8 or 9 peed cassette with your 10 speed chainset and use a 9 speed chain. Modern 9 speed mechs such as 3500 Sora will work just fine though your present mechs almost certainly will also.
    I have run thus set up on a bike of similar vintage with no problems whatsoever, and even with the 6 speed FREEWHEEL it had at first, the transmission worked perfectly.
    regarding the crankset, I would advise using a square taper one .The bottom bracket shell faces on your frame won't be as receptive to Hollowtech 2 external bearings as a modern frame which has been designed for that type of bottom bracket.
    I would advise against a 10 speed chain if your sticking with your old mechs.It didn't seem to run as happily as a 9 speed.

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