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  1. #1
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    9 speed crank, 8 speed chain...

    Any problem with doing this? I'm running 8 speed drivetrain and want to put a new LX crank on with 9 speed rings.

  2. #2
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    What you'll want to do is run a 9 speed chain on that 8 speed cassette of yours.

    Because 9 speed chains are a touch narrower than 8 speed, the shifting ramps on 9 speed chainrings "reach in" just a bit further, and can potentially cause conflict.

    On the other hand, 9 speed chains perform well on 8 speed cassettes.

    I ran a similar setup myself for two seasons -- XT 8 speed cassette, LX 9 speed rings and a Sram 9 speed chain -- and it was flawless.
    speedub.nate
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  3. #3
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    Go with the 8sp chain

    Quote Originally Posted by RetroG
    Any problem with doing this? I'm running 8 speed drivetrain and want to put a new LX crank on with 9 speed rings.

    I run a sram pc68 chain with a deore mega 9 m510 crankset and m570 lx gold edition derailleurs front and rear with a pg 850 cassette and it shifts like butter. The 9 speed chains are MUCH weaker than the 8 speed setup I run lx m570 derailleurs both front and back and get 0 chainrub in any combo I use sram twisties 2002 Centera shorty's and don't even have to trim the front. That said 9 speed chains break too easy. especially if your are a clyde and a masher. I have never broken a 8 speed chain but used to eat 9 speeds for breakfast so I went back to 8 speed for much better shifting and durability
    Last edited by danoalb; 07-30-2006 at 08:56 PM.

  4. #4
    Mantis, Paramount, Campy
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    Just Curious...

    What part of the chain were you breaking?
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  5. #5
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    Coupla of different spots

    Quote Originally Posted by Shayne
    What part of the chain were you breaking?

    One chain I broke the inner rollers (snapped) and another the outer link pins snapped. Just don't think they are tough enough. They were the cn 7701 shimano chains never tried the 9 speed sram chains but with the 8 speed chain I have never snapped one. They wear out before they fail. I'll never go back to 9 speed. I run a 11 - 32 sram pg 850 cassette now and love it. Shifts so smooth under any condition and torque. I happen to think the Sram cassette and chain combo is the smoothest and strongest setup I have experienced and I have tried them all except the Rohloff. I'm not a fan of 9 speed as it was the answer to a problem that never existed. In the nasty mud the 8 speed really loses the 9 speed stuff in the dust.

  6. #6
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    8spd chain the way to go

    I run everything 9spd except for the cassette, right shifter and the chain. Never a problem. The drive train is all XTR except an XT crankset.

    This is the best drive train ever assembled and it should go in production. By the way XTR 8spd steel cassettes rule.

  7. #7
    Weird huh?
    Reputation: cmdrpiffle's Avatar
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    marketing

    My setup:

    9 speed SRAM cassette
    XT cranks
    SRAM XO front and back


    8 speed chain.

    Everything works, shifts like buttah.........chain is $8.00 bucks cheaper than the 9 speed version. BTW its a SACHS or SRAM or whatever they're calling it now, silver version.
    And don't do the burrito jump... Francois

  8. #8
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    my setup mix

    Here's my set up, which is flawless......

    raceface 9 spd chainrings
    8 spd xt front derail
    9 spd rear drail
    8 spd sram PC68 chain
    XTR 8 spd 11-32 ti cassette

    shifts perfect in all conditions, mud, snow, sleet or rain

    8 speed is just stronger than 9 spd, plain and simple.
    I weight in at 225 with gear, so stonger is better...

  9. #9
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    I just bought a XT FC-M751 ( Mega 9) crankset and was wondering the same thing. Everything at the back is 8 speed XTR. I woulda gone with the newer stuff but the prices are still too steep for me.
    From the sounds of it Shimano 8 speed chains still aren't the better choice. I'm running an old Sachs chain (over 9 years old) on my 8 speed LX drivetrain bike with an XTR 8 speed ti cassette, still shifts good too.
    Did SRAM buy out Sachs?
    I need to get a new chain for the new "old" ride. Guess the pc68 is the better choice now?

  10. #10
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    This thread has been helpful and answered a lot of my questions. It sounds like for the most part 8 speed and 9 speed stuff is interchangable.

    My mountain bike has an XTR 8 speed drivetrain and SRAM PC-68 chain. However, I just ordered The newer XTR M960 crankset. This should work right? I weight in at a hefty 260 pounds all loaded up. I don't know if it would be wise to switch to a 9 speed chain. Especially when putting a lot of torque on the drive train climbing steep hills. I may have a beer gut but can still hammer the trails with the best of them...

    My other bike has a 9 speed SRAM X.7 drivetrain and is used mostly on paved and dirt paths. The rear cassette on this beast is an el cheapo steel SRAM thingy. It weighs a ton. I have a few spare XT 8 speed rear cassettes. It sounds like I could just slap one of these on as long as I adjusted the rear deraileur stop appropriately, correct?

    Thanks,

    Gerb

  11. #11
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    Nope...

    Quote Originally Posted by gerbermultit00l

    My other bike has a 9 speed SRAM X.7 drivetrain and is used mostly on paved and dirt paths. The rear cassette on this beast is an el cheapo steel SRAM thingy. It weighs a ton. I have a few spare XT 8 speed rear cassettes. It sounds like I could just slap one of these on as long as I adjusted the rear deraileur stop appropriately, correct?

    Thanks,

    Gerb
    You cant shift an 8 spd cassette with a 9spd shifter. To use your 8spd cassettes you'd have to swap to an 8spd shifter.


    Also as to 9spd vs 8spd chain strength there is a very miminal difference between them. The pins are the same size and the cage plates I believe are 5% thinner. Overall wear time should be the same. i guess there could be an increased chance in bending?!? the chain or having it break mid plate but how often does that happen.
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  12. #12
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    Quote Originally Posted by Shayne
    You cant shift an 8 spd cassette with a 9spd shifter. To use your 8spd cassettes you'd have to swap to an 8spd shifter.
    Please elaborate. Why not? Have you tried this?

    Gerb

  13. #13
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    They are indexed differently. The spacing for the shifts are shorter with the 9 speed shifters because the gears on the cassette are closer together. You can not use them on a 8 speed (wider spacing between gears) cassette. Try it for yourself...

  14. #14
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    Quote Originally Posted by jx0shawn
    They are indexed differently. The spacing for the shifts are shorter with the 9 speed shifters because the gears on the cassette are closer together. You can not use them on a 8 speed (wider spacing between gears) cassette. Try it for yourself...
    I had a suspicion this was the reason. No need to try. I understand entirely. Perhaps I will sell the spare cassettes and buy what I need.

    Gerb

  15. #15
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    How old are the cassettes and what shape are they in?

  16. #16
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    Wow, i had no idea that you could successfully run an 8spd chain on a 9spd cassette. Very informative thread. Thanks MTBR.
    When under pressure, your level of performance will sink to your level of preparation.


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  17. #17
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    That's Questionable....

    It might work on a 'MTB' cassette, ie 11,12-32,34 but it sure doesnt work on a 'road' cassette. The diameter of the cogs is so similar that the pins of the 8spd chain even though they're only a fraction of a mm wider will catch the ramps on the cassette and the chain will chatter and ghost shift.
    I inadvertently grabbed the wrong chain off my work bench when finishing off my commuter this spring and it shifted like crap and I couldnt figure out why. LBS was mystified as well, tried new housing and cable, tried different derailleur, tried new derailleur hanger...the alignment was spot on per the Park dropout and derailleur hanfer tools, so finally we broke out a new chain and tried that. Problem solved. The 8spd chain worked in some gear combinations on the 9spd cassette but had a mind of its own on the smaller cogs.
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  18. #18
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    Quote Originally Posted by jx0shawn
    How old are the cassettes and what shape are they in?
    One is brand new, the other only has a few rides on it. I received an XTR cassettes free so decided to use it instead.

    Just trying to put some of my spare parts to good use.

    Gerb

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