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  1. #1
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    Who makes post to post mount rear adapters???

    I have a Stumpy Carbon hardtail and the rear brakes are post mount, not IS. I am not looking for IS to post adapters, I need post to post.

    The stock brakes are Avids which I want to get rid of, but the adapters are avid specific because they have the cone macined into them for the CPS system.

    Who makes post mount spacer/adapters for the rear???

    Thanks

  2. #2
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    Actually, you should be able to use the Avids adapters for other post mount brakes. I use Avid adapters all the time with my Shimano brakes. The Avid caliper accounts for the CPS washers. The only thing to watch out for is Avids uses a 185mm rotor, while many others are 180mm, but you did not mention changing rotors.

  3. #3
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    Quote Originally Posted by RSabarese View Post
    Actually, you should be able to use the Avids adapters for other post mount brakes. I use Avid adapters all the time with my Shimano brakes. The Avid caliper accounts for the CPS washers. The only thing to watch out for is Avids uses a 185mm rotor, while many others are 180mm, but you did not mention changing rotors.
    I thought about this but those adapters don't seem very solid with the coned cut out for the CPS system. Certainly someone else out there makes adapters...

  4. #4
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    Interesting, all the adapters I've seen from Avid are flat, not concave. Can you post a photo? What year is your stumpy? What size rotor are you running?
    I wonder it it follows the same pattern as IS? Meaning, 160mm rear, is pretty much the same as 180mm front. If that hols true, you may get away with a 180mm front adapter on the rear. Let's see if pics can help us out though as I have not heard of post mount rear.

  5. #5
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    Lots of new bikes have post mount rear now as it is lighter and stiffer then IS with an adaptor. Unless you are using a DH bike or a Clyde then you wouldnt really need anything bigger then the stock 160mm rotor size. If you want better modulation or heat dispersion get better brakes, bigger rotors won't quite compensate. With that in mind, any 160 front will work as a 140 rear, any 180 front will work as a 160 rear, etc. And as for the hope 183 size or avids 185 size. Usually they are all compatible. If the rotor is hitting throw some washers in.

  6. #6
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    Quote Originally Posted by Lipster94 View Post
    Unless you are using a DH bike or a Clyde then you wouldnt really need anything bigger then the stock 160mm rotor size. If you want better modulation or heat dispersion get better brakes, bigger rotors won't quite compensate.
    My original post says nothing about going bigger, only wanting to get away from Avid. I am planning to stay at 160mm rotors as this is a dedicated race bike, although I am a clyde. For the record, I want to run XTR race brakes.

  7. #7
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    Quote Originally Posted by RSabarese View Post
    Interesting, all the adapters I've seen from Avid are flat, not concave. Can you post a photo? What year is your stumpy? What size rotor are you running?
    I wonder it it follows the same pattern as IS? Meaning, 160mm rear, is pretty much the same as 180mm front. If that hols true, you may get away with a 180mm front adapter on the rear. Let's see if pics can help us out though as I have not heard of post mount rear.
    These are not your conventional adapters as you will see in photos below. Stumpy HT Carbon is 2011 with 160mm rotors. In the front, there is no adapter as usually you just mount 160mm brakes directly to the fork, but these are avid so you have the CPS stack as well. Check out my pics of the rear set up. They are more like spacers than adapters... Note the different heights as well. Also pictured is a close up of the spacer with the cone shape and how the cps cone mates up...








  8. #8
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    Quote Originally Posted by Lipster94 View Post
    With that in mind, any 160 front will work as a 140 rear, any 180 front will work as a 160 rear, etc. Usually they are all compatible. If the rotor is hitting throw some washers in.
    Good info on 180 front =160 rear and I will have to try that out.

    Yeah, you will see I am running some washers right now to try to get better pad contact with my XT rotors, but I really think the biggest issue is the BS CPS mounting system. I don't know how they think they will ever get a solid mounting platform stacking 4 pieces on top of eachother. Just more components to cause vibration... Of course me adding washers to the stack only increases the potential for chatter

  9. #9
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    After I posted similar info, I found your frame on the spesh website. It says the post mounts are 140mm and 160mm rotor, so that stands to reason you should be able to get a 180mm front post mount and it will bolt up fine to a 160mm rear. Infact, looking at your pics, it says 140mm front with 160 rotor, so I think you're okay to buy the 180mm rear.

  10. #10
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    Just spent some time looking at the Specialized website and the 2012 models and I do not think using a 180 post mount adpater will work in this case, but I will have to try it before I say for certain.

    If you do a zoom in on any of the carbon bikes that use non avid brakes and have a 160mm rotor in the rear, you will see the adapter I am looking for. On a front post to post adapter, it staggers the caliper in one direction offset from the adpater to fork mounting bolts and this also sets the correct alignment with the rotor.

    On the new bikes with 160mm rear post mount, the adapter does not stagger. It just uses one bolt rhough the caliper, through the adapter and into the frame. Not sure why I am having such a hard time finidng this adapter.

    The XTR Sworks stumpy and the Expert Stumpy have different brakes, one XTR Shimano and one Formula R1, but htey are using identical rear adapters.

    I havebeen to the Shimano sites, Formula site, and am unable to find a 160mm rear post adapter

  11. #11
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    @ebnash- did you ever figure this out? I am having the exact same problem with my rear breaks on my 2013 giant reign 2. The rear brake has the weird spacer/adapters as the picture above. this thread is the only thing i have found

  12. #12
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    Quote Originally Posted by MercerClub View Post
    @ebnash- did you ever figure this out? I am having the exact same problem with my rear breaks on my 2013 giant reign 2. The rear brake has the weird spacer/adapters as the picture above. this thread is the only thing i have found
    Universal cycles-->Brakes & Brake parts, disc--> disc brake adapters

    I've used Shimano and Magura
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  13. #13
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    Glad I found this as I have a 2012 Stumpy with the same adapters for my Elixirs...I think a Shimano 180 front will work as it is listed to work with a 160 rear.
    Geologist by trade...bicycle mechanic (former) by the grace of God!

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  14. #14
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    It was a pain to get adapters for my Spech Camber 2012 rear shimano 160 to 180 post to post. No one stocks it even on the internet only one store had one. The tektro brakes that came on the bike have a very similar shaped adapter but the exact fit of my XT brakes is not correct which prevents them from stopping (without the shimano brand adapter).
    Last edited by Trail_Blazer; 08-22-2014 at 07:44 PM.

  15. #15
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    Isn't this just a 20mm adapter? The same as the most 160 to 180 front? These are common.
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  16. #16
    rebmem rbtm
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    Front post mount adapters work on the rear.


    160mm post mounts + 180mm rotor
    or
    140mm post mounts + 160mm rotor =


    Who makes post to post mount rear adapters???-tf-br2032-2.jpg
    Who makes post to post mount rear adapters???-691793d1335387562-xtr-180mm-post-mount-adaptor-problems-xtr.jpg



    160mm post mounts + 200mm rotor
    or
    140mm post mounts + 180mm rotor =



    Who makes post to post mount rear adapters???-509_1.jpg




    160mm post mounts + 203mm rotor =

    Who makes post to post mount rear adapters???-4109_0.jpg


    * If you want to use a 200mm or 203mm rotor on 140mm post mounts you'd need to use 2 adapters

  17. #17
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    Re: Who makes post to post mount rear adapters???

    You forgot one thing:

    Easy mistake because Shimano reused their model numbers too much for most people or internet searches to distinguish.

    160 to 180 Post to Post Rear and Front are completely different.

    The three confusing model numbers are:

    XTR SM-MA-90 F180 P/P Front Adapter
    Current SM-MA-F180 P/P2 Front Adapter
    Retired SM-MA-F180 P/P Front/Rear Adapter

    The Rear one looks like a triangle.

    Photo comparison:

    Shimano Front vs. Rear
    160 to 180 Post to Post adapters.

    FRONT


    REAR
    Last edited by Trail_Blazer; 08-24-2014 at 02:12 PM.

  18. #18
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    I recently had to buy one of these Rear 160-180 P/P adapters and there was only one site on the internet that had this model:

    http://www.coloradocyclist.com/product/item/SSXAHQ51/



    This Rear P/P Model should not to be confused with the P/P2 model.
    The P2 model number only fits the Front but not the Rear.

  19. #19
    rebmem rbtm
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    You're giving a bit of wrong info there and you didn't need to buy the adapter you did, you could of used any of the 3 adapters you mentioned on the rear as they all do the same thing.

    SM-MA-F180P/P = Old 180mm post mount adapter that isn't made anymore
    SM-MA-F180P/P2 = Current 180mm post mount adapter
    SM-MA90-F180P/P = XTR Lightweight version of the SM-MA-F180P/P2 adapter.

    The 'F' in the adapter model codes stands for 'Front' and it's fairly common knowledge that 'Front' post mount adapters also work on rear post mounts.

    Name:  61543-9ce5e3c20187ef5be947c34360b8d29f-400-400.jpg
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    The old 'triangle' adapter that isn't made anymore it isn't a 'rear' adapter as you say, it's a 'Front' post mount adapter that can also be used on the rear.

    Shimano has never made a 'Rear' post mount adapter or called an adapter a 'Rear Post Mount Adapter'.

    As you can see the SM-MA-F180P/P2 works on rear post mounts.

    Who makes post to post mount rear adapters???-zr-bremse-h01.jpg

    Front Post Mount adapters can be used on Rear Post Mounts because Rear Post Mounts have the same specs as Front Post Mounts.

    Who makes post to post mount rear adapters???-front-pm.jpg
    Who makes post to post mount rear adapters???-rear-pm.jpg

  20. #20
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    Look, your bike with post mounts is set up stock for a certain size rotor. At that size, you don't need an adapter. Example..my Stumpjumper HT is set up in the rear for PM 140 and the front PM 160. I run a 180 in the front so I need a 20mm PM adapter. In the rear, I run a 160 so I need a 20mm PM adapter...its the same on mine front/rear..its just a 20mm spacer same front/rear.
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  21. #21
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    I didn't intend post wrong info really so I understand why you wanted to clarify that this adapter can be front or rear.

    So, I'm not trying to start something but you did add confusion when you respond to my post saying that I bought the wrong post adapter.

    I have the correct adapter for my bike and rotor size.

    This is the 160-180 P/P Rear brake adapter that came on my Specialized Camber 29 2013 (not exactly old).



    Shimano retired it for some fool reason, probably the same greedy reason they started ispec-b and stopped making the old a version available anymore.

    I am just adding my real world experiance with my bike using these adaters.

    I'm not trying to debate truth vs false on a grand scale of every bike ever made.
    Last edited by Trail_Blazer; 08-24-2014 at 07:43 AM.

  22. #22
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    Quote Originally Posted by ebnash View Post


    I have found that with these spacers on the front(Manitou Circus Expert 100mm), I keep bending the long screw that holds he brake caliper. Switching to a Ti screw has solved that issue. If using post spacers, use Ti screws, or the torque that goes through the bolts will eventually bend the long bolt. The Hayes and Shimano 160mm to 180mm front brace brake adapter distributes the torque evenly along the two bolts and the rail connecting the bolts, lessening the capability for the bolt to bend.

    $0.02 of experience.
    Happy Trails!

  23. #23
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    Quote Originally Posted by Trail_Blazer View Post
    That one (triangular) unit is the only rear 180 P/P brake adapter that will work on my bike.
    Did you try a SM-MA-F180P/P2 or a SM-MA90-F180P/P ?

    Looking at your post mounts I can see no reason at all why either of those adapters would not work.

    I didnt post wrong info really.

    I posted info about the alternate model of rear brake adapter my bike 2012 (not exactly old) and many bikes require.
    You said the SM-MA-F180P/P2 adapter doesn't work on rear post mounts when it does.

    Who makes post to post mount rear adapters???-zr-bremse-h01.jpg

    You also said the only adapter that works on your frame is an old superseded model that's hard to find.

    You can claim that shimano never intended it to be a rear adapter but yet many thousands of new specialized bikes are equipped with this as a rear adapter and its the only one that fits.
    So I dont think your clain is accurate that its Not a rear used as adapter.
    Because it is by my manufacturer did and apparently there are some people other on the forum who need them for their bikes too.
    Like me, for my 2012 Camber.
    When these adapters were first made there was no frames with post mounts on them, that's why they are called 'Front' adapters.
    Shimano hasn't bothered to change the model code for these adapters to indicate that can be used on front and rear post mounts.
    The code for these adapters also doesn't take into account that not all post mounts are at 160mm specs, when the 180mm adapter is used on 140mm post mounts it's a 160mm adapter not a 180mm adapter.

    Avid used to call their 180mm post mount adapters a 'F' or 'Front' adapter, they have since changed the name of these adapters to '20mm Post' because it can be used on front and rear, it can also be used on different size post mounts too. On 160mm post mounts it increases the rotor size by 20mm to 180mm, on 140mm post mounts it increases the rotor size by 20mm to 160mm.

    I very much doubt the SM-MA-F180P/P is the only adapter that will fit on your bike as you've said.

    Parts manufacturers have been known to supply bike manufacturers with old discontinued stock at cheap prices to get rid of it.

    I recently had to buy one of these Rear 160-180 P/P adapters and there was only one site on the internet that had this model:

    Shimano 180mm Ft. Post To Post Adaptor
    It's an old superseded model, that's why it's hard to find.

    Shimano retired it for some fool reason, probably the same greedy reason they started ispec-b and stopped making the old available anymore.
    Maybe like several other companies that used to make similar adapters, they realized that they could make a lighter weight adapter that did the same thing and only needed to use two bolts instead of four.

    .........
    I didn't intend post wrong info really so I understand why you wanted to clarify that this adapter can be front or rear.
    Last edited by Trail_Blazer; 6 Hours Ago at 12:43 AM.
    Maybe you should edit some of your other posts too?

    I'm not trying to start something but you did add confusion when you respond to my post saying that I bought the wrong post adapter.
    I have the correct adapter for my bike and rotor size.
    I didn't say you had the wrong adapter, I said you could of used any of the three Shimano adapters that you previously mentioned.



    Remember the following thread?

    from 160 to 200mm Brake Adapter?

  24. #24
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    Im so glad you are able to communicate Cobba but I wish you weren't so offensive.
    Still, no need to quote me for examination guys.
    Forgive me for trying to contribute. (rolleyes)

    The only thing I intended to do was to add one additional item to the long list of post mount adapters that have been listed by other people.

    I was mistaken it's not a REAR only, it's either way F or R.

    Yet it wasn't on the long list of known P/P adapters cobba originally posted, so I made it known.
    Last edited by Trail_Blazer; 08-24-2014 at 04:52 PM.

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