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  1. #1
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    post to post adaptor for 180 post to 203 rotor

    The new Fox 36 has post mounts for a 180 mm rotor. Meaning you can run a 180 mm rotor without an adaptor. I am looking to run a 203 rotor. I am having trouble finding the correct adaptor. It has been suggested to get a 160 to 180 adaptor, but I am not convinced. Anyhow, anyone with specific knowledge on what adaptor to get and where to get one is appreciated.
    Last edited by Monster Truck; 07-09-2014 at 08:29 PM. Reason: spelling

  2. #2
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    A 160mm to 180mm PM to PM adapter is basically a +20mm adapter, Avid now calls their 180mm PM to PM adapter the '20mm Post' adapter because there's different size post mounts and it can be used on them all.

    140mm post mounts + '20mm Post' adapter = 160mm rotor
    160mm post mounts + '20mm Post' adapter = 180mm rotor
    180mm post mounts + '20mm Post' adapter = 200mm rotor
    200mm post mounts + '20mm Post' adapter = 220mm rotor

    With a '20mm Post' adapter or a 160mm to 180mm PM to PM adapter on 180mm post mounts you'd need about 1.5mm of extra packing under the caliper to place it in the correct position for a 203mm rotor.


    A 160mm to 183mm post mount to post mount adapter is basically a +23mm post mount adapter, on 180mm post mounts it should place the brake caliper in the correct positionfor a 203mm rotor.

    http://www.chainreactioncycles.com/h...r/rp-prod13728
    http://northshorebillet.com/shop/pos...brake-adapter/

  3. #3
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    Thanks, that should be easy enough

  4. #4
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    Follow up. To recap I am running a 203 front rotor on the new Fox 36. It comes with 180 post mounts. I need an adaptor to go 180-203, which is an item that does not exist by that name. So I purchased a Hope 160-183 Post to Post adaptor. It works perfectly with my Shimano XT brake. The rotor is in proper alignment with the pads and all is well in the universe. The key is that it is a +23mm adaptor. Good pics on Northshore Billet for install orientation.

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  6. #6
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    Quote Originally Posted by Monster Truck View Post
    The new Fox 36 has post mounts for a 180 mm rotor. Meaning you can run a 180 mm rotor without an adaptor. I am looking to run a 203 rotor. I am having trouble finding the correct adaptor. It has been suggested to get a 160 to 180 adaptor, but I am not convinced. Anyhow, anyone with specific knowledge on what adaptor to get and where to get one is appreciated.
    I work at a shop and just talked to fox today about this -- i was trying to mount a 200 icetech to my 36 and thought all i would have to do is use the 160-180 adaptor (20mm increase). Fox doesn't suggest this, though. They make a specific unit for a 200mm post mount for the 36. It's $20 and you can order it directly from them -- which i would say is worth it. I've stripped post mounts out on a fork before and that sucks. 20 bucks to insure your $1200 purchase is worth it.

    I also checked to see if Shimano was making anything specific for the 36 and couldn't find anything.

    Cheers -

    Ben

  7. #7
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    Quote Originally Posted by benhack View Post
    I work at a shop and just talked to fox today about this -- i was trying to mount a 200 icetech to my 36 and thought all i would have to do is use the 160-180 adaptor (20mm increase). Fox doesn't suggest this, though. They make a specific unit for a 200mm post mount for the 36. It's $20 and you can order it directly from them -- which i would say is worth it. I've stripped post mounts out on a fork before and that sucks. 20 bucks to insure your $1200 purchase is worth it.

    I also checked to see if Shimano was making anything specific for the 36 and couldn't find anything.
    * The two 183mm (+23mm) post mount adapters I linked above will do the same job as the Fox adapter.
    * Ice-Tech rotors are 203mm not 200mm
    * You could of used a +20mm adapter (160 to 180mm adapter) but you would of needed an extra 1.5mm of packing under each side of the the caliper to space it properly for a 203mm rotor.
    * Fox wouldn't suggest you do that as they have their own adapter they want you to buy
    * The Fox adapter won't stop you from stripping threads, you can strip threads with it just like you can strip threads with any other adapter if you tighten the bolts too much.

    When this thread started the Fox adapter wasn't available, now that it is there's another adapter that will do the same job as the Hope & NSB 183mm (+23mm) post mount adapters.


    Hope 183mm (+23mm) post mount adapter + Shimano brake + Shimano 203mm Ice-Tech rotor

    post to post adaptor for 180 post to 203 rotor-7e9759f8-a0cc-4df3-b7f2-1a87a7e8fc87.jpg

  8. #8
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    Shimano now makes a couple of 23mm adapters for fitting 203mm rotors onto 180mm post mounts.

    Standard version: SM-MA-F203P/PM
    XTR version: SM-MA90-F203P/PM

    The 180 to 203 adapters are basically the same as the 160 to 180 adapters, they're just a little bit bigger.

    XTR & Standard 180 to 203 adapters: http://si.shimano.com/php/download.p...000-00-ENG.pdf
    Standard 160 to 180 adapter: http://si.shimano.com/php/download.p...0A-001-ENG.pdf
    XTR 160 to 180 adapter: http://si.shimano.com/php/download.p...0A-001-ENG.pdf
    Last edited by cobba; 08-30-2015 at 07:21 AM.

  9. #9
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    Hey guys i need some help. So bought a used bike and it has this combo for the front brake. Ihave fox 36 180 mm and i have a 203 mm disc on it with avid elixir 5. I went for a short ride and the brake works fine, but i am wondering isnt there supposed to be an adapter a 203 mm post mount? As you can see all i have is some washers betwen the caliper and fork mount.

    You can also see that the brake pads fit the rotor nicely and there is no unused rotor surface. But still shouldnt there be an adapter? Or do some fox 36s have brake mount straight for 203 mm brakes?


  10. #10
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    Hope is the only brand i know that makes one. Chain reaction is the only place i have seen it.

    Sent from my GT-I9505 using Tapatalk

  11. #11
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    Quote Originally Posted by 3names View Post
    Hey guys i need some help. So bought a used bike and it has this combo for the front brake. Ihave fox 36 180 mm and i have a 203 mm disc on it with avid elixir 5. I went for a short ride and the brake works fine, but i am wondering isnt there supposed to be an adapter a 203 mm post mount? As you can see all i have is some washers betwen the caliper and fork mount.

    You can also see that the brake pads fit the rotor nicely and there is no unused rotor surface. But still shouldnt there be an adapter? Or do some fox 36s have brake mount straight for 203 mm brakes?
    Some Fox 36's did came with 203mm post mounts, I think they might all have 180mm post mounts now.

    Re. the washers under the caliper, some but not all Avid calipers need those washers to place the caliper in the correct position over the rotor, your caliper is a model that needs those washers.

    All looks good with your setup, if you ever change to a different brand of brake, you will have to remove those washers.

    Quote Originally Posted by love_that_flow View Post
    Hope is the only brand i know that makes one. Chain reaction is the only place i have seen it.
    Shimano, Formula & Fox also make 23mm adapters (180mm post mount to 203mm rotor).

  12. #12
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    I agree with cobba, all looks good. consider yourself fortunate that you get a little weight savings
    2015 Santa Cruz 5010 C

  13. #13
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    Has anyone used the SM-MA-F203P/PM on a rear brake (I am using XT M785 brakes)?

    I keep destroying 180 rear rotors on long downhill runs while my 203 front stays quiet and doesn't turn black/blue, even when I use the rear sparingly, and I'm hard on the front. . . . . Still squeals like an undead banshee.

    Ice Tech rotors don't seem to be any help either. Maybe worse than lower end non-sandwich'd rotors. Nothing new for me. I have always had to resort to 203 mm rotors front and back eventually.

    I'll probably also go back to resin pads from the metallic ones I am currently using, but I want to have braking to spare out back like I have up front.

  14. #14
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    Quote Originally Posted by jeffj View Post
    Has anyone used the SM-MA-F203P/PM on a rear brake (I am using XT M785 brakes)?
    Do you have 180mm post mounts on the rear?

  15. #15
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    Quote Originally Posted by cobba View Post
    Do you have 180mm post mounts on the rear?
    Doh!!! A Homer Simpson moment. . . . . Not sure what I was thinking

    No, it has 160 post mount. Couldn't I just add a 180 to 203 adapter to the top of the 160 to 180 adapter?

    LOL, just kidding! Certainly would not go that lo-tech even if it were possible.

    Thanks for pulling my head out of a bad place

  16. #16
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    Quote Originally Posted by cobba View Post
    Shimano now makes a couple of 23mm adapters for fitting 203mm rotors onto 180mm post mounts.

    Standard version: SM-MA-F203P/PM
    XTR version: SM-MA90-F203P/PM

    The 180 to 203 adapters are basically the same as the 160 to 180 adapters, they're just a little bit bigger.

    XTR & Standard 180 to 203 adapters: http://si.shimano.com/php/download.p...000-00-ENG.pdf
    Standard 160 to 180 adapter: http://si.shimano.com/php/download.p...0A-001-ENG.pdf
    XTR 160 to 180 adapter: http://si.shimano.com/php/download.p...0A-001-ENG.pdf


    Can you use Shimano adaptors with Sram guide brakes?

  17. #17
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    Quote Originally Posted by Fullblitz View Post
    Can you use Shimano adaptors with Sram guide brakes?
    Yes, but the adapter that you will need will have to be the right one for the rotor that you are going to use.

  18. #18
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    Magura QM26

    $10 online at Jenson, Universal, Art's, etc.

  19. #19
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    RockShox pike soloair 27.5 . Right now there is a 200 mm rotor.

    I'l install saint br-820 with rt86 203 mm rotor.
    Which adapter do i need?
    I-SMMA90F203PPM
    I-SMMAF203PPA
    E-SMMAF203PPM
    OK

  20. #20
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    Quote Originally Posted by ka81ua View Post
    RockShox pike soloair 27.5 . Right now there is a 200 mm rotor.

    I'l install saint br-820 with rt86 203 mm rotor.
    Which adapter do i need?
    I-SMMA90F203PPM
    I-SMMAF203PPA
    E-SMMAF203PPM
    If you have 160mm post mounts and are currently using a 40mm Post adapter you would need a SM-MA-F203P/P

    If you have 180mm post mounts and are currently using a 20mm Post adapter you would need a SM-MA-F203P/PM or a SM-MA90-F203P/PM

  21. #21
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    Quote Originally Posted by cobba View Post
    SM-MA-F203P/PM or a SM-MA90-F203P/PM
    what's the difference?
    OK

  22. #22
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    The latter is the lighter XTR version, they both do exactly the same thing.

    Pikes have 160mm post mounts don't they?

  23. #23
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    Quote Originally Posted by cobba View Post

    Pikes have 160mm post mounts don't they?
    Right now I don't have that fork next to me so unfortunately I can't answer that. Maybe someone else knows...
    OK

  24. #24
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    Quote Originally Posted by benhack View Post
    I work at a shop and just talked to fox today about this -- i was trying to mount a 200 icetech to my 36 and thought all i would have to do is use the 160-180 adaptor (20mm increase). Fox doesn't suggest this, though. They make a specific unit for a 200mm post mount for the 36. It's $20 and you can order it directly from them -- which i would say is worth it. I've stripped post mounts out on a fork before and that sucks. 20 bucks to insure your $1200 purchase is worth it.

    I also checked to see if Shimano was making anything specific for the 36 and couldn't find anything.

    Cheers -

    Ben
    Part number for the 200mm post mount for the fox 36? I find plenty of adapters for the 203mm, but not the 200mm.

  25. #25
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    Quote Originally Posted by spikebike View Post
    Part number for the 200mm post mount for the fox 36? I find plenty of adapters for the 203mm, but not the 200mm.
    Ice-tech rotors are 203mm not 200mm, there's a mistake in that post you quoted.

    If you want to use a 200mm rotor on a fork with 180mm post mounts, use a Shimano SM-MA-F180P/P2 adapter, it's basically an adapter that increases the rotor size by 20mm, on 160mm post mounts you would use a 180mm rotor with it, on 180mm post mounts you would use a 200mm rotor with it.

  26. #26
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    Quote Originally Posted by spikebike View Post
    Part number for the 200mm post mount
    00.5318.007.003
    https://www.bike-components.de/en/Av...-to-PM-p29820/
    OK

  27. #27
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    Quote Originally Posted by ka81ua View Post
    That's for a 200mm rotor on 160mm post mounts, it's not for a 200mm rotor on 180mm post mounts.

    For a 200mm rotor on 180mm post mounts you would use any of the following adapters which increase the rotor size by 20mm......
    https://www.bike-discount.de/en/buy/...nt-180mm-37435
    https://www.bike-components.de/en/Ma...160-mm-p42967/
    https://www.bike-components.de/en/Av...-to-PM-p43632/ * don't use all the washers supplied unless needed.
    https://www.bike-components.de/en/Tr...mse-20-p32887/
    https://www.bike-discount.de/en/buy/...tmount-6-54443
    https://www.bike-discount.de/en/buy/...m-db020-419512

  28. #28
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    Old topic, I know. Since I googled the issue and this seems to be the most complete topic around, I'm adding a bit more of information.

    I have used on the rear an adapter +20mm with two valve nuts (the round ones) for a 203mm ICE rotor. I had measured the thickness of the nuts in 2.95mm, or 1.45mm beyond recommended. Looking closely, it is further out than the 160 to 203 adapter I have on the front. Still the pads are sitting fully on the rotors.

  29. #29
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    torontocycles sells trick 1.5mm drilled Titanium washer spacers that do the trick for inline adapters.

  30. #30
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    Quote Originally Posted by FactoryMatt View Post
    torontocycles sells trick 1.5mm drilled Titanium washer spacers that do the trick for inline adapters.
    Sounds good. However a new adapter costs USD 10, while the two washers cost USD 5+5 for delivery. My suggestion was using stuff that most people have at home.

  31. #31
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    3mm is too thick imo - better off going to the hardware store. but yes.

  32. #32
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    I was afraid 3mm would be too thick. In my case it worked, but is not assured will work in every case. In all cases, I agree - a good set of washers in the right thickness would be better.

  33. #33
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    Just adding knowledge to the database >>

    The new 2020 Pike Ultimate 35mm stanchion X 120-160mm travel forks use a native 180mm post brake mount, so this fork requires a 23mm adapter, or a 20mm adapter with a 1.5mm spacer to run 203 rotors. The Shimano adapter is better, in my opinion, than spacers for this structural function. Also, pay attention to the length of the hex-head mounting bolts. If you are upsizing from 180mm you will probably need longer bolts to go to 203mm … in my case 30mm length on bottom and 20mm on top since the top bridge on the adapter is not as wide as the bottom bridge. This will make sense when you look at your adapter.

  34. #34
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    2mm works fine. It shims the very top of the pad off the rotor but to the best of my judgement doesn't matter. However, I think the SHimano F203 adapter rather than a spacer is the way to go to prevent wobble-gobble.

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