can you use a 9speed crank with an 8speed drive train

Discussion in 'Mountain Bikes' started by eXtremebiker, Aug 26, 2004.

  1. eXtremebiker

    eXtremebiker New Member

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    I have a 2003 trek 4900 with an 8speed drive train but my crank is shot and I'd like to upgrade to an LX crankset will that work
     
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  2. Juba

    Juba New Member

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    That is a situation that could potentially work.

    8 speed chains are slightly thicker then 9 speed chains. What you might find is that when you are in your middle ring, your chain might rub or catch on your big ring, which may lead to chain suck. Same when you are in your small ring, your chain might catch on your middle ring. Also, it might be kind of tricky to set your front shifter up to properly, assuming your shifter is for a 24 speed drivetrain.

    That is worst case. It could also go error free. Chainrings and front derailleurs can be mysterious things at times.

    If you get the crankset, and you are having problems, you would probably be able to solve the problems with washers. 1 metal washer on each bolt point, between your crank spider and middle chainring. 2 metal wasters on each bolt point between your crank spider and small chainring. This will spread your chain rings out a bit, so they will be compatable with your thicker chain and 24 speed shifter. You can experiment a bit with the thickness of the washers to fine tune things.

    Cheers,
    Juba
     
  3. cachehiker

    cachehiker New Member

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    I've done this myself on an old GT with Alivio shifters and crank. Use a 9 speed front derailleur and a 9 speed chain with your 9 speed crank and it will work pretty well. The rear derailleur is already 9 speed and the new chain will work just fine with the 8 speed shifters and cassette.

    Next time you crash and thrash a shifter, buy a 9-speed replacement and replace the cassette too.
     
  4. Banatean

    Banatean New Member

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    Sure you can,most Shimano Deore or other levels advertise Mega Range 9... :) ,that's totally compatible with your 8 sp drive.
    Dan :eek:
     
  5. Greg-O

    Greg-O New Member

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    yes, it will work. just use a 9 speed chain.
     
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