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  1. #1
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    XTR WH-M975 to 15MM QR Conversion?

    So I'm making the move to a 15mm QR fork, but I would like to keep my XTR wheel set. Shimano doesn't officially make an XTR wheel set with a thru-axle, although you can see it on sponsored riders bikes. However, they do make an XTR hub only with a thru-axle and an XT wheel set with a thru-axle. Without busting out the calipers and micrometers it seems like a conversion is possible using various internals from the parts above. Here are a couple of scenarios to chew on:

    1. Will the XTR QR hub internals fit directly in the M975 wheel set?
    2. If you bought the XT front wheel or could get the hub internals, would they fit directly in the XTR wheelset?
    3. Choice of last resort, cut out the XT wheel set hub and lace it to the XTR rim?

    I'm just thinking out loud here, drinking coffee and viewing tech sheets on the internet. Has anyone ripped apart any of these hubs and done some experimenting?

  2. #2
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    There is no 24 spoke version of the HB-M978 15mm front hub, so you can't simply replace the WH-M975 front hub.

    There's no way to replace the 14mm alloy axle in the WH-M975 front hub with the 15mm thru axle, unless you were prepared to do some major machining and switch to some sort of sealed bearing. The outer diameter on the 15mm hub axle is 20mm, so there'd be no room for loose bearings.

    It appears that even the hub body is different on the 15mm and 20mm hubs as well, they use different size balls in the bearing and have a different bearing race, so they don't appear to be interchangeable.

    It is mind bending that there is no XTR 15mm version of the wheel since it was developed by Fox/Shimano. I suppose they must look at it as a non-race item so XTR hasn't bothered to go there as a wheelset.

    If you could get a replacement WH-M778 front hub for the XT 15mm wheel you could lace that to the lighter XTR rim.
    I'm a member of NSMBA and IMBA Canada

  3. #3
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    So I talked with a Shimano tech guy and no dice across all scenarios, but he did mention a possible mid year release of a QR, XTR wheel. However, I'd still place that in the rumor column for now.

  4. #4
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    you can do this

    Quote Originally Posted by rockyuphill
    If you could get a replacement WH-M778 front hub for the XT 15mm wheel you could lace that to the lighter XTR rim.
    I did this and it worked GREAT!!!

  5. #5
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    here is a link to pics of my bike.

    http://forums.mtbr.com/showthread.ph...89214#poststop

  6. #6
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    I knew it, it's a darn Shimano Cover up.

    Were you able to get the hub outright, or did you have to part out a wheel? Can you get me a parts list?Build pics?

  7. #7
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    ????

    Quote Originally Posted by MFKracing
    I knew it, it's a darn Shimano Cover up.

    Were you able to get the hub outright, or did you have to part out a wheel? Can you get me a parts list?Build pics?

    Where's the cover up?

    I bought a WH-M778 XT front wheel and a WH-M975 XTR front rim. SHIMANO part number I-WHRIM1BFDBD.
    If you look on techdocs.shimano.com you can find all of their part numbers.
    here's a link to the XTR F wheel EV (Exploded View)

    http://techdocs.shimano.com/media/te...9830608660.pdf

  8. #8
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    I just like conspiracy theories.

    It stemmed from the Shimano Dude telling me the spoke length would be all jacked up. But it sure looks liked it worked for you and Adam Craig all year.

  9. #9
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    I dont now why he would say that unless he was thinking of changing the hub of a WH-M975 wheel with something else. You would not be able to change the hub because they are diferent sizes but the rims are exactly the same.

  10. #10
    Ride More Work Less
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    I really need to upgrade and now see that the XTR M985 24 hole front hub is 15mm thru axle. Any ideas how to purchase this hub? The spokes are 2mm shorter than my M975 wheel spokes. Would I really need new spokes too?

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