i have some new brakes comeing in the mail and ive been thinking about the best way to mount them.

ive been looking at p2p brackets for the front but most of them look like they still require a long bolt and about 35 and 1/2 spacers, i dont know about you guys but i hate the look of excessive bolt length and spacers on any project. is there any bracket that will let me mount a 180mm p2p front caliper and a 160mm is2p rear caliper with minimal spacers and a clean look? 2 small washers per bolt would be an ideal mark as it give that bit of adjustability without the mess.

There's 2 types of 180mm post adapters, one adapter uses 2 longer bolts, the other type of adapter uses 4 smaller bolts.





* That 4 bolt adapter isn't made by Shimano anymore but a couple of companies still make that type.

Avid makes post spacers.



* You need to be careful with these as there's 2 versions for each size, one version is for CPS calipers and the other version is for non CPS calipers.
If you use the CPS post spacers on non CPS calipers your pads will overhang the outer edge of the rotor by about 5mm.
Non CPS post spacers won't give enough clearance with a CPS caliper.

https://www.sram.com/sites/default/f...r_mounting.pdf

A 160mm rear PM to IS adapter only comes in one basic type.

ok thankyou, i was wondering what the difference in the 2 pictured 180mm adapters was.

i dont like the standard 2 bolt that uses long bolts as in your pictures as like i mentioned they always need a ton of spacers. think my rear one has like 6 per bolt? seems alittle excesive to need that many for a mount made for a 160 mm rotor, just how much variation can one 160mm rotor have from another? i would think adabpter>washer>caliper>washer>bolthead would be more then suficent adjustment and would offer a much cleaner look and less parts that can shift around.
and my current front is the pictured avid post spacer as it came with avids and im getting away from them as fast as i can haha. but they have something like 8 washer per bolt......

on the rear however i have a 4 bolt is2p like pictured at the bottom and it still had long bolts. is there no variation that has longer arms at the " post " end for a beter fit? really seems these things would be designed better considering all of the advances in other areas of the bike.

think ill buy a set of shimano xtr adapters to go with my shimano brakes and if i have to ill make some custom black spacers, i have some dence pvc tube in black that i use for that purpose.

Adapters don't always need a ton of spacers.


160mm rotors don't vary.

Sounds like you have a CPS calipers, they are spaced differently to a standard caliper and need extra packing underneath them.

Never seen 8 washers per bolt, maybe you should post some photos.

Non CPS calipers would use bolts that are 10mm shorter as they don't require CPS washers.

Why would you need to make custom spacers, just use the proper adapters, attach the calipers to them how they were meant to be attached and stop worrying about how they look. it's not a fashion parade.



Front adapter = SM-MA-F180P/P2 or SM-MA90-F180P/P
https://si.shimano.com/php/download.p...0A-001-ENG.pdf
https://si.shimano.com/php/download.p...0A-001-ENG.pdf
* The concave/convex washers are required under the bolt head as the bolt head isn't parallel to the top of the caliper.

Rear adapter = SM-MA-R160P/S or SM-MA90-R160P/S
* 4 bolts + 4 small flat washers under the bolt heads

The MA90 adapters are the magnesium XTR adapters.

* Non Avid brakes don't use the concave/convex CPS washers underneath them.