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  1. #1
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    XT FC-M760 Cranks w/ XT 737 8-Speed Cassette??

    I have a 1996 Giant ATX-880 with the original ST-Cranks and ST-Shifters... I've upgraded the wheels to a set with XT hubs and currently have two wheel-sets setup with XT 737 8-Speed Cassettes... one for commuting and the other for MTB... I'm currently using an IG style chain.

    I'd like to install a set of FC-M760 cranks, and have been told that these will work fine with the XT 737 8-speed cassettes as long as I switch to an HG-91 or HG-93 chain.

    Basically, I'd just like some reassurance that this combo is going to work. I can't afford to upgrade all the shifters, cassettes, etc... especially since the cassettes are almost brand new now...

    Am I heading for trouble, or can the XT FC-M760 Cranks, XT 737 8-speed Cassette, and HG-91 or 93 chain work fine??

    Thanks,
    Darin
    Last edited by Banzai240; 05-19-2008 at 08:55 AM.

  2. #2
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    It'll work fine with an 8spd chain
    I wouldn't switch to a 9spd chain, if that's what the 91/93 is. 8spd chain works fine on 9spd cranksets.
    Why not just get new rings instead of new crankset & BB?
    ST cranks/shifter??
    Quote Originally Posted by Banzai240
    I have a 1996 Giant ATX-880 with the original ST-Cranks and ST-Shifters... I've upgraded the wheels to a set with XT hubs and currently have two wheel-sets setup with XT 737 8-Speed Cassettes... one for commuting and the other for MTB... I'm currently using an IG style chain.

    I'd like to install a set of FC-M770 cranks, and have been told that these will work fine with the XT 737 8-speed cassettes as long as I switch to an HG-91 or HG-93 chain.

    Basically, I'd just like some reassurance that this combo is going to work. I can't afford to upgrade all the shifters, cassettes, etc... especially since the cassettes are almost brand new now...

    Am I heading for trouble, or can the XT FC-M770 Cranks, XT 737 8-speed Cassette, and HG-91 or 93 chain work fine??

    Thanks,
    Darin
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  3. #3
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    Quote Originally Posted by logbiter
    Why not just get new rings instead of new crankset & BB?
    I'm 230lbs and I've always hated the way the STX-RC cranks flex when I put the power down... They've been on there for 12-years and have served me well, however... Only one BB change in all that time... It's time for an upgrade to something lighter and stiffer... and LOOKS nicer!



    Quote Originally Posted by logbiter
    ST cranks/shifter??
    I know, I know.... I'm working on it! The shifters are actually Grip Shift SRT-600s... They work fine for what I'm doing... The Cranks are currently STX-RC, not STs like I previously stated (still STs in my mind...)....

    After I get the new cranks installed... I go to work on getting a new shifter system... I'm kind of attached to the GripShift after all this time, so I'll likely stick with what works for me...

    If anyone else has any experience with the Crank/Chain/Cassette combo I mentioned above and wants to chime in, I'm all ears... I just don't want to head down that road only to find out I need to scrap the XT Cassettes or get a new derailure to make this work...

    Thanks,

  4. #4
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    Grip shift is cool, I've used both over the years and prefer trigger shifters (can't say I've tried sram's new triggers). you can still grab some decent SRAM attack shifters for a good price on the interwebtailers.
    I'ma clyde too & never had flex issues with my 'oldschool' deore/lx/xt/raceface square taper cranks, though I can't say the same of some others.
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  5. #5
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    Well... it doesn't hurt that I got the XTs for $180.00 at my LBS... I think they are 07s.... Even the shop salesman was a little suprised that they were marked at this price...

  6. #6
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    Update:

    OK, I've updated my thread because I realized that I was actually getting the XT FC-M760 crankset, not the 770 as I originally thought...

    Either way... I now have installed the XT-760 Hollowtech II cranks, along with a new LX Rear Derailure. I decided, after a little research, to go with an SRAM chain instead of the Shimano chain... I got the SRAM PC-850 8-speed chain...

    I installed the cranks as the directions show, with two shims on the chainring side and one on the other... I'm questioning this a little bit, as it looks like this may offset the crank to the right one shim too much, but we'll try it for now... Also installed new Shimano M540 pedals as well...

    I put the entire removed crank assembly, including UN70 BB, M535 pedals, and older LX Deore rear derailure on the scale and it all weighed 3lbs 3oz... The replacement parts weighed in at 2lbs 11oz... so I saved about 8oz or 1/2lb in this upgrade... Not too shabby for $250.00 and WAY stiffer cranks to boot...

    Everything seems to work great... shifting is precise and crisp. Cranks are as smooth as can be... The entire ride is now noise free... you don't even hear or feel the chain turning over...

    Only glitch I've noticed is that every now and then, when you really put down some power, the chain seems to skip a tooth or tries to jump a gear... I'm playing with the adjustment as I ride this week, so I'm hopeful I can stop this from happening... I'm also going to investigate the removable dropout being slightly bent... I noticed that the rear derailer seems to hang inward at an angle just a bit, and I did take a spill awhile back that could have tweaked this section.

    Overall... a worthwhile investment to this point... Sure is nice to have some stiff cranks under me... and the crisp shifting has been sorely missed as well!

  7. #7
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    All the Shimano X type BB cranks are setup for 50mm chainlines not the 47.5-48mm chainlines of the XT 737, so you will likely need to adjust the limit screws on the front derailleur.
    When using an old cassette with new chainrings and chain you can expect some skipping on the old cassette as it will be worn in to the old chain and chainrings. You need to replace the cassettes as well.

  8. #8
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    Another Update:

    This combo is working great... I elimiated the skipping by removing 4-links from the new chainset. Turns out the stock length was too long, so when I'd shift to smaller chainrings, the rear derailure had almost no tension on the chain and it would skip... Now shifting is smooth and precise... Haven't had any issues at all.

    These cranks are worlds stiffer than the old STX-RC cranks. The whole package makes riding just a little bit more fun.

    The only complaint I have at this point is that the 44-tooth chainring on this crankset has messed up my preferred gearing that I had setup for the 42-tooth ring on the old cranks... Used to be that 5th gear was my ideal cruising gear for commuting, which would yield around 17-18mph on average for the 15-miles I ride to work (and then back home...)... Now I use 4th, but it's not QUITE as high a gear as 5th used to be, and 5th is now just a touch too high for some sections or when I start to get tired... Guess I'll just have to get into better shape!!

    Thanks for the help, guys! I'm very happy with the updates I've done...

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