XT M8000 1X 165mm boost cranks

Discussion in 'Parts 'n Stuff' started by EsPeGe, Apr 14, 2017.

  1. EsPeGe

    EsPeGe Likes Dirt

    Hey all hope everyone has saddle sores from all the riding. Anyway I've just scored a new Pivot Mach 429 Trail which runs boost cranks. Unfortunately the cranks on it are 170mm and I run 165mm. I can't find any XT M8000 boost cranks in 165mm only 170 and up. The shimano website doesn't even mention the boost standard for XT which is frustrating. Does anyone out there know if they make these cranks in 165mm or gave any decent info on them?

    Cheers Scott.

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  2. JTmofo

    JTmofo XC Enthusiast

    Hey mate, part number you are looking for for boost 1x XT cranks is

    FC-M8000 B1

    Looks like 170mm is the shortest in boost that they make.

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  3. EsPeGe

    EsPeGe Likes Dirt

    Cheers mate. Pretty much what I found. Very frustrating if that's the case. Apparently short people don't ride bikes with boost. I'll keep searching but I'm not feeling positive.

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  4. JTmofo

    JTmofo XC Enthusiast

    I've go a set of M9000 1x in 170mm (that's my short Arse requirement) on my hardtail. I've also got some raceface cinch (Turbine) on my dually.

    Great thing about raceface direct mount stuff is that the cranks remain the same, so there's no boost specific crank. The direct mount ring denotes the chain line, so you can change the cranks from boost to non boost by changing the ring only.

    I like that.

    Just checked, and you can get Atlas (30mm spindle) aswell as Next and Sixc in 165mm.

    You'll need new bb tho.
  5. EsPeGe

    EsPeGe Likes Dirt

    Yeah not really sure what I'm gonna do. Even though it's only 5mm 165's do feel more comfortable for me so I would prefer to stick with them. Will have a look at the set up you are talking about if I can't find any XT/XTR's.

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  6. SummitFever

    SummitFever Likes Bikes and Dirt

    You could go with the previous series XT 165mm cranks and mount the ring on the outside (big ring position). Just make sure you get the 3x version and not the 2x version.
  7. moorey

    moorey Isn't flammable.

    170mm with thick pedals. You're welcome.

    Fuck clipless, if that's the case.
  8. JTmofo

    JTmofo XC Enthusiast

    Or get yourself a pair of these? (Vegan friendly?)[​IMG]

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  9. Mr Crudley

    Mr Crudley Likes Bikes and Dirt

    Those shoes are made for disco.

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  10. EsPeGe

    EsPeGe Likes Dirt

    Might be an option but I've done a heap of reading and it would seem that I may be able to use the standard M8000 cranks and the chainline shouldn't be adversely affected. The only thing I need to keep an eye on would be the size of the front ring which seems to be the limiting factor. It looks like the biggest ring I can run up front is 34T which will be fine although on some occasions I would prefer a 36T.

    Cheers Scott.
  11. Andrey

    Andrey Squid

    Race face have a 165mm Boost option if you would consider moving away from Shimano.

    This is the link for the 165mm Boost compatible Race Face Atlas cranks: https://www.raceface.com/products/details/atlas-cranks

    Unfortunately they are quite expensive & you would probably have to get a new bottom bracket to suit a 30mm spindle (I believe Shimano's spindle is 24mm) & new chain ring.

    I currently have 175mm Raceface AEFFECT cranks and would like to move to 165mm. I would like shorter cranks for increased ground clearance.
  12. Shinigami

    Shinigami Likes Dirt

    i've seen mention that the non boost cranks may have a better chainline for 1x boost given the chainline position on the outer ring
  13. EsPeGe

    EsPeGe Likes Dirt

    Same here, I think the thing for me now is whether or not I can run a 34 or a 36T chainring without it hitting the chainstay.
  14. EsPeGe

    EsPeGe Likes Dirt

    Cheers mate. I definitely reccomend going to 165mm crank arms if you are shorter. Way less rock strikes and feels better ergonomically for my stumpy legs.
  15. EsPeGe

    EsPeGe Likes Dirt

    Had I read Pivot's 429 Trail FAQ section first I could have saved everyone some time although in fairness I am surprised they answer this one.

    Screenshot 2017-04-17 20.06.35.png

    Now all I need to do is check and see if a 34 will go on there.
  16. Shinigami

    Shinigami Likes Dirt

    The 34 should fit as long as it's the outer ring, and as Shimano stock It default on some 2x drivetrains it should be sweet
    Last edited: Apr 18, 2017
  17. EsPeGe

    EsPeGe Likes Dirt

    So my XT cranks turned up and I fitted them along with an SLX M7000 34T chainring. It all went on a breeze and looks to have plenty of clearance. Interestingly I think CRC ballsed up and sent me 2X crank arms instead of 1X even though it said 1X on the box. The spider is definitely 2X. Does anyone know, does shimano just use the same spider for 1X and 2X setups on the XT M8000 stuff? Would this affect chainline?

    Anyway below are some pics. The chainline looks pretty parallel (even though you can't really tell from the pic) but I will put a caveat on that by saying whilst I have a pretty good eye for stuff like that I'm not sure I could tell if it was a couple of mm out in this case.



    About 4.5mm to the wide teeth

    About 5mm to the narrow teeth

    Cheers Scott.
  18. Ultra Lord

    Ultra Lord Likes Bikes and Dirt

    They do. It's just a few extra tapped holes, nothing to worry about though
  19. JTmofo

    JTmofo XC Enthusiast

    Yep. Same cranks for 1x and 2x. 1x chainring has a different offset to achieve the right chain line.

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  20. EsPeGe

    EsPeGe Likes Dirt

    Sweet. Thanks dude

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