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Want to upgrade from 180mm to 203mm rotors. Post mount, direct mount - which adapter?

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Want to upgrade from 180mm to 203mm rotors. Post mount, direct mount - which adapter?

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flag Tall7kiwi
Posted: Feb 12, 2019 at 14:08 Quote
Hi guys, I am wanting to upgrade my brake rotors from 180mm to 203mm. I currently have RockShox Yari on my 2017 Trek Remedy 7. The current adapter that the caliper is sitting on is the SM-MA-F180P/P2. I am unsure as to what adapter I would need to buy so I can install the 203mm rotor. There are so many options and I am thoroughly confused.

Any help would be great Smile
flag Davec85
FL
Posted: Feb 12, 2019 at 15:08 Quote
You want post to post mount for 203 rotor.

sm-ma-f203p/p2
flag Tall7kiwi
Posted: Feb 12, 2019 at 15:17 Quote
Davec85 wrote:
You want post to post mount for 203 rotor.

sm-ma-f203p/p2

Is there any difference between the SM-MA-F203P/P2 and the SM-MA-F203P/P?
flag Tall7kiwi
Posted: Feb 12, 2019 at 22:05 Quote
cobba wrote:
Tall7kiwi wrote:
Davec85 wrote:
You want post to post mount for 203 rotor.

sm-ma-f203p/p2

Is there any difference between the SM-MA-F203P/P2 and the SM-MA-F203P/P?

1. there is no such thing as a SM-MA-F203P/P2 adapter.

2. there is a 160-203mm (+43mm) SM-MA-F203P/P adapter.

3. there is a 180-203mm (+23mm) SM-MA-F203P/PM adapter.

Excellent. Thats the information I need. I guess I would just use the same type of mount for front and rear?
flag Hammer48
Posted: Feb 13, 2019 at 0:11 Quote
cobba wrote:
Tall7kiwi wrote:
I guess I would just use the same type of mount for front and rear?

Post mount adapters aren't front or rear specific.

Are you sure about that..? Went from a 160 mm in the rear to a 180 mm rotor, and by mistake, I ordered a front mount. It did not fit, I then checked, and sure enough there is Rear post mount for Shimano rotors.
flag Hammer48
Posted: Feb 13, 2019 at 16:25 Quote
cobba wrote:
Hammer48 wrote:
Are you sure about that..? Went from a 160 mm in the rear to a 180 mm rotor, and by mistake, I ordered a front mount. It did not fit, I then checked, and sure enough there is Rear post mount for Shimano rotors.

Yep.

A Shimano rear specific brake adapter would be for attaching a post mount brake onto IS brake mounts, this thread is about attaching a post mount brake onto a frame/fork with post mounts.

Shimano doesn't make a post mount adapter that's labeled rear because the front adapters work on the rear


SRAM just label their PM adapters with 20mm or 40mm
20mm adapter on 140mm post mount = 160mm rotor
20mm adapter on 160mm post mount = 180mm rotor
20mm adapter on 180mm post mount = 200mm rotor
40mm adapter on 140mm post mount = 180mm rotor
40mm adapter on 160mm post mount = 200mm rotor

Shimano PM adapters....
SM-MA-F180P/P2 = 20mm
SM-MA-F203P/PM = 23mm
SM-MA-F203P/P = 43mm

140mm post mount + SM-MA-F180P/P2 = 160mm rotor
160mm post mount + SM-MA-F180P/P2 = 180mm rotor
160mm post mount + SM-MA-F203P/P = 203mm rotor
180mm post mount + SM-MA-F203P/PM = 203mm rotor

I see. I checked and and bought the SM-MA 180 adapter mount which specifies a rear mount..

Thanks for the correction.
flag Tall7kiwi
Posted: Feb 14, 2019 at 12:03 Quote
cobba wrote:
Hammer48 wrote:
Are you sure about that..? Went from a 160 mm in the rear to a 180 mm rotor, and by mistake, I ordered a front mount. It did not fit, I then checked, and sure enough there is Rear post mount for Shimano rotors.

Yep.

A Shimano rear specific brake adapter would be for attaching a post mount brake onto IS brake mounts, this thread is about attaching a post mount brake onto a frame/fork with post mounts.

Shimano doesn't make a post mount adapter that's labeled rear because the front adapters work on the rear


SRAM just label their PM adapters with 20mm or 40mm
20mm adapter on 140mm post mount = 160mm rotor
20mm adapter on 160mm post mount = 180mm rotor
20mm adapter on 180mm post mount = 200mm rotor
40mm adapter on 140mm post mount = 180mm rotor
40mm adapter on 160mm post mount = 200mm rotor

Shimano PM adapters....
SM-MA-F180P/P2 = 20mm
SM-MA-F203P/PM = 23mm
SM-MA-F203P/P = 43mm

140mm post mount + SM-MA-F180P/P2 = 160mm rotor
160mm post mount + SM-MA-F180P/P2 = 180mm rotor
160mm post mount + SM-MA-F203P/P = 203mm rotor
180mm post mount + SM-MA-F203P/PM = 203mm rotor

Thanks for your help. I put through an order for a couple of SM-MA-F203P/P adapters Smile
flag ka81
Posted: Apr 14, 2020 at 3:37 Quote
Hello.
Some questions bout adapters.
It's PM180 on chainstay of frame. I use 180 mm rotor.

What "4-bolt" adapter (links, please) do I need to install rotor through the adaptor?
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