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  1. #1
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    Adaptor for disc brake mouting on forks?

    HI. I am trying to mount a XTR M-965 disc brake on a Manitou Minute fork. If the rider were looking down at the front brake, my XTR caliper's mounting bolts screw on from left to right, perpendicular to the direction of bicycle travel (same as any rear brake, although this is the front brake). The Minute's bolt holes accept these screws in a direction parallel to the direction of bicycle travel. In other words, the fork accepts the brake bolts in a direction 90 degrees from how the brake was designed to mount. What adaptor is available to alleviate this problem? It seems kind of silly to have different methods of mounting calipers on different forks.

  2. #2
    simply me
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    Manitou forks use the 'post mount' system, most other fork manufacturers use IS mounts, the brake set you bought happens to be available in either standard, you have the IS version. Adapters are available from most LBS's to convert but you may also need a larger dia rotor. You are better off swtiching for the correct caliper if the brake is still as new.

  3. #3
    Lightweight Ghost Rider
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    What bostonkiwi said - also, the correct caliper is BR-M966.

  4. #4
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    You'll need a 74mm post mount to IS converter as well as a 170mm or larger rotor. Its better if you can just get the correct caliper for it.

  5. #5
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    Oh Great! How silly for every manufacturer to have their own method of doing things! I don't really feel like buying a new caliper and hose and dealing with the hassle setting it up, so I guess I will just get a different fork! Does Fox use the IS standard?

  6. #6
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    If you are using a 6" rotor, try taking the mount off of the caliper. The bolts holding the mount to the caliper should be parallel to the bikes movement. Then try to mount the caliper directly to the fork. I know this works for the Avid Mechanicals and may be worth a try before you go hunting for the right parts and new rotor.

    Brandon.

  7. #7
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    Quote Originally Posted by BrandonAggsMntnBk
    If you are using a 6" rotor, try taking the mount off of the caliper. The bolts holding the mount to the caliper should be parallel to the bikes movement. Then try to mount the caliper directly to the fork. I know this works for the Avid Mechanicals and may be worth a try before you go hunting for the right parts and new rotor.

    Brandon.
    That won't work because shimano's IS mounts are a fixed machined part of the caliper. Avid and Hayes only make 74mm post mount calipers and use adapters to mount it on IS type forks. The 74mm post mount XTR 966 caliper could be adapted to either post or IS mount the same as the Avid/Hayes but not the IS mount XTR 965.

  8. #8
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    Quote Originally Posted by Hecubus
    That won't work because shimano's IS mounts are a fixed machined part of the caliper. Avid and Hayes only make 74mm post mount calipers and use adapters to mount it on IS type forks. The 74mm post mount XTR 966 caliper could be adapted to either post or IS mount the same as the Avid/Hayes but not the IS mount XTR 965.
    Thanks for the help. It probably would be silly to run a 203mm rotor up front,and may not be recommended with the XTR caliper anyway. Buying another caliper seems silly, but may be the only option, unless I go with a Fox TALAS instead of the Minute One (I was looking forward to the coil and saving some $). What do you think I can sell a very lightly used front caliper XTR M-965 on Ebay for? Also, what the difference between the XTR and XT 2-piston caliper-I notice the XT is $15 cheaper and 50 grams lighter.

  9. #9
    Chrome Toaster
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    Quote Originally Posted by dawgcatching
    Thanks for the help. It probably would be silly to run a 203mm rotor up front,and may not be recommended with the XTR caliper anyway. Buying another caliper seems silly, but may be the only option, unless I go with a Fox TALAS instead of the Minute One (I was looking forward to the coil and saving some $). What do you think I can sell a very lightly used front caliper XTR M-965 on Ebay for? Also, what the difference between the XTR and XT 2-piston caliper-I notice the XT is $15 cheaper and 50 grams lighter.
    The XTR can run 203mm rotors. Shimano is supposed to even be releasing an 8" center lock rotor specifically for the new XTR's. I had to go through the same thing when I switched to a Minute 3. I sold my IS XTR caliper on ebay for $80 and got the post mount version. The new XT caliper is basically the same thing except it weighs a bit more.

  10. #10
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    It is an issue with the ISO fork attachment strength.

    Quote Originally Posted by dawgcatching
    Oh Great! How silly for every manufacturer to have their own method of doing things! I don't really feel like buying a new caliper and hose and dealing with the hassle setting it up, so I guess I will just get a different fork! Does Fox use the IS standard?
    Manitou doesn't feel the ISO standard is strong enough. There are brakes that attach to the Manitou style, like Hayes and Avid, so Manitou hasn't yielded to the standard. Lest you think they are being too conservative, you should know that some manufacturers have experienced failures of the ISO tabs, particularly when using larger rotor sizes. For example, Fox limits the rotor size with some of their forks and Specialized actually recalled the front brakes on a Fox fork equipped bike, to replace them with a smaller size.

  11. #11
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    part numbers?

    anyone got an adapter for '02 shimano xt calipers to mount to a manitou fork? or a p/n? thanks, scott

  12. #12
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    You can check our website for the adapter you need.

    www.discbrakeadapters.com

  13. #13
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    thanks

    thats what i need. where are you located? what do you charge for shipping? scott

  14. #14
    If you have to ask...
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    Manitou has got it right.

    Current motorcycle racing brakes have HUGE rotors, and calipers of mind-boggling strength. To allow this level of force on the leg, the manufacturers are going with what are called "Radial Mount" calipers. They are (yep, you guessed it) pretty much just like the post-mount design that Manitou forks have.
    The idea is that traditional-mount (or IS in Bicycles) calipers create strong shear and torsional force against the leg, but Manitou/Radial mount calipers distribute force evenly into a larger, thicker casting.

    miles
    Attached Images Attached Images

  15. #15
    simply me
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    The downside to the postmount system is if you cross thread or other wise screw up the mount your lowers are toast.


    Quote Originally Posted by miles
    Current motorcycle racing brakes have HUGE rotors, and calipers of mind-boggling strength. To allow this level of force on the leg, the manufacturers are going with what are called "Radial Mount" calipers. They are (yep, you guessed it) pretty much just like the post-mount design that Manitou forks have.
    The idea is that traditional-mount (or IS in Bicycles) calipers create strong shear and torsional force against the leg, but Manitou/Radial mount calipers distribute force evenly into a larger, thicker casting.

    miles

  16. #16
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    helicoil

    could fix that.

  17. #17
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    Quote Originally Posted by Hecubus
    The XTR can run 203mm rotors. Shimano is supposed to even be releasing an 8" center lock rotor specifically for the new XTR's. I had to go through the same thing when I switched to a Minute 3. I sold my IS XTR caliper on ebay for $80 and got the post mount version. The new XT caliper is basically the same thing except it weighs a bit more.
    It sounds like replacing the caliper will be the better option for me, over getting the adapter and new rotor. If I can get $80 for the used caliper and get a new one here for under $100, then it is the cheaper option as well. Does the XTR M-966 caliper (post-mount compatible) have adjustment for rotors or forks/hubs slightly out of spec, like the Avid's do? this is a concern for me-I was working on a Hayes HFX-9 post-mount version today (on a Manitou Black) and adjustment range was very narrow.

  18. #18
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    Why silly to run a 203?

    and how about the Saint caliper, hows that differ from xt/xtr? Will a Minute handle that size rotor? And will my '02 xt brake lever and hoses work on '04 calipers? Its a banjo type fitting on the caliper. Thanks, scott.

  19. #19
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    Quote Originally Posted by scottay
    thats what i need. where are you located? what do you charge for shipping? scott
    Our website automatically calculates shipping based on weight, your location and the method of shipping you prefer. You can e-mail me at sales@discbrakeadapters.com with your info and I can give you an estimate. Thanks.

  20. #20
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    Quote Originally Posted by miles
    Current motorcycle racing brakes have HUGE rotors, and calipers of mind-boggling strength. To allow this level of force on the leg, the manufacturers are going with what are called "Radial Mount" calipers. They are (yep, you guessed it) pretty much just like the post-mount design that Manitou forks have.
    The idea is that traditional-mount (or IS in Bicycles) calipers create strong shear and torsional force against the leg, but Manitou/Radial mount calipers distribute force evenly into a larger, thicker casting.

    miles
    Strange my truck has "ISO style" mounts and stops a lot more weight, my dads dump truck has disc brakes and they are mounted the same way, between the truck and trailer you are looking at almost 200,000lbs.
    Pat T.

  21. #21
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    New question here. Where did you find one?

    Quote Originally Posted by dawgcatching
    It sounds like replacing the caliper will be the better option for me, over getting the adapter and new rotor. If I can get $80 for the used caliper and get a new one here for under $100, then it is the cheaper option as well. Does the XTR M-966 caliper (post-mount compatible) have adjustment for rotors or forks/hubs slightly out of spec, like the Avid's do? this is a concern for me-I was working on a Hayes HFX-9 post-mount version today (on a Manitou Black) and adjustment range was very narrow.
    Like you, Just got a Minute and already have xtr discs. Where did you get the caliper if thats the way you went? How did it work out? TIA, Rob

  22. #22
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    I went the adapter and 203 disk way, I'm running a Manitou Black Super and it's approved my Manitou to run 203 rotors on it.

    I'm using the "old" M755 XT Hydros and couldn't find a post mount version, the only option that I was able to find was to upgrade to the new XT/XTR caliper and that was a more expensive solution.

    Where to get the parts? Your only option is your friendly neighborhood LBS, Shimano doesn't allow e-tailers to sell parts on line. Lucky for me the shipping guy from the e-tailer that I got my parts from shipped them by mistake. E-tailers are only allowed to sell complete products. E-tailers like Jenson and others sell other brand rotors that come in the 203 size.
    Last edited by DiRt DeViL; 04-05-2004 at 11:58 AM.

  23. #23
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    ok Postmount versus IS mount
    When the IS standard was born Manitou was the only person who objected ( actually the main person, who objected is no longer at Manitou ) . They found an friend in the Dia Compe disc brake, and later with Hayes . Hayes than came out wwith their own stuff and delivered what their main customer at the time wanted ( that was Trek )

    Rockshox was instrumental in testing and pushing for the IS ( together with all Disc brake manufacturers ) The involvement from Rockshox was in my opinion the ONLY reason for the postmount (For their DH forks Manitou came up with all together 3 different IS look alike mounting points at the time ???remember the Xvert and Xvert TI )

    Infinite strength testing in various labs and universities all over the world proved that IS is the way to go. But Manitou had a big customer with Trek and Hayes had a big customer with Trek, both together had a nice portion of the market locked in.
    Not at all a bad MARKETING decision. ( I am NOT flaming Manitou in any way, I like the guys, and again they made the correct for them decision at the time )

    In other words, its not all black and white , and the postmount had to be changed from 68 to the current 72 mm in order to faciliate larger rotors and to spread the load better.

    Now if you take into cnsideration that every brake manufacturer has to make molds or bracketery to mount on either one, and the cost involved , the looser is the consumer, as he usually picks up the extra cost involved to offer both systems.

    But its not all that bad really. After all we have to deal with 2 different systems and not 20 different anymore. Check out the Motorcycle Industry, they all have different hubs, different nounting points ( mostly like IS ) every different Motorcuycle has different rear sprocket and front sprocket mountings and so forth ... Much better in the bike biz.

    Brakemeister

  24. #24
    Flyin Canine
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    Quote Originally Posted by Pat T.
    Strange my truck has "ISO style" mounts and stops a lot more weight, my dads dump truck has disc brakes and they are mounted the same way, between the truck and trailer you are looking at almost 200,000lbs.
    Pat makes some good points here. It seems to me that the IS mounts place the loads on the cross section of the bolts and the metal surrounding the hole where the bolt goes through the fork leg. The post or radial style places the pulling forces on the THREADS of the lower bolt. The threads are the weakest part of the bolt and I can't understand why anyone would do this.

    Keep in mind that just because the "motorcycle" industry does something doesn't mean it's smart. I have a Kawasaki Ninja ZX-6R so I am into that stuff and I'l tell you this much. The engineers and marketing people in the motorcycle biz absolutely have to make changes to their bikes every year to catch the customers eye and make them buy new stuff. The competition among sportbikes is so tough that they seem to sometimes make changes to just grab the spotlight. Not all of these changes make a noticeable improvement but the customers can't tell the difference because 99% of them don't push the bikes to the limit. I don't see how the changing of the bolt placement is going to change the torsional forces exerted on the fork leg either. That would seem to be caused by the inboard location of the caliper in relationship to the center line of the fork leg. Changing the bolts does not change this relationship.

    Another thing. I have heard that the 185mm limits on most forks are not about the IS bolts or mounts breaking but the issue of force exerted on the QR axle and making sure that the QR axle doesn't come out of the dropout. That's why the 200mm rotors are mostly approved for 20mm axle model forks.

  25. #25
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    I've got a Shimano 74mm post-mount to IS adapter and a 170mm Shimano rotor for sale. Send me an e-mail or PM me if interested.
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