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ShimanoDisc Brake Adapters

Sale $7.15 - $12.99

Item # SHI0108

77
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  • SM-MA-R160, IS/Post Rear ($8.00)
  • SM-MA-R180, IS/Post Rear ($12.99)
  • SM-MA-F180P, Plus 20mm Post Mount ($10.99)
  • SM-MA-R203, IS/Post Rear ($12.99)
  • SM-MA-F160, IS/Post Front ($8.00)
  • SM-MA-F180, IS/Post Front ($12.99)
  • SM-MA-F203 (160mm to 203mm), IS/Post Front ($8.00)
  • SM-MA-F203 (160mm to 203mm), Post/Post Front/Rear ($8.00)
  • SM-MA-F180, IS/IS Front ($7.15)
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Item # SHI0108
Description

Like much of life, making your Shimano disc brakes work with your 160mm rotor is easy --once you learn how to figure out which adapter you need. Whatever you have, we can either sell you the adapters to make it work, or tell you that what you have is enough.

You need to know three things -- what kind of mount your Shimano disc caliper is, International Standard (ISO) or post mount. If it goes on the front, you need to know what your fork is: ISO, post-mount, or a few special cases (Marzocchi 20mm axle, Boxxer-type). And, you need to know the rotor size that you're trying to fit -- in this case, it's 160mm.

If you're trying to diagnose what you already have and/or what you need, here's how to do it. The Shimano adapters all have a model number that starts with SM. The Mount Adapter acronym is MA. Front brake is F. Rear brake is R. Rotor Size is 160, 180, or 203. Caliper Mount Type will be S for ISO/International A, and P will represent Post. And the last letter will be for the frame or fork mount type: S for ISO/A, P for Post, B for Boxxer, Z for Marzocchi 20mm Axle as well as QR20Plus and DH ISO. Thus an adapter that reads SM-MA-F-203S/P is Shimano Small Parts Mount Adapter Front 203mm Rotor with ISO caliper on a Post type fork.

  • Durable alloy construction
  • Mounting hardware included
  • Compatible with ISO and post-mount calipers and frames/forks

Weight

Actual Weight

SM-MA-R160, IS/Post Rear
610g
21.52oz
SM-MA-R180, IS/Post Rear
610g
21.52oz
SM-MA-F180P, Plus 20mm Post Mount
610g
21.52oz
SM-MA-R203, IS/Post Rear
610g
21.52oz
SM-MA-F160, IS/Post Front
28g
0.99oz
SM-MA-F180, IS/Post Front
28g
0.99oz
SM-MA-F203 (160mm to 203mm), IS/Post Front
28g
0.99oz
SM-MA-F203 (160mm to 203mm), Post/Post Front/Rear
34g
1.20oz
SM-MA-F180, IS/IS Front
47g
1.66oz
Weight is for brake adapter with hardware.

Actual weights are measured in-house by the Competitive Cyclist team.

Have questions? Chat with a Gearhead

What do you think about this product?

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Is the SM-MA-F203 (180mm to 203mm), Post/Post Front/Rear the correct adapter to go from 180 to 203 on a 2019 RockShox Lyrik fork?

Exact fit

Familiarity:
I've put it through the wringer
Fit:
True to size
Size Bought
160-203 p2p
Height
5` 9"
Weight
180 lbs

Purchased to go from 160 to 203 post to post. No washers needed other than what came with it. Beat on the bike and it holds alignment just fine

What is the length of the bolts for the + 23mm adapter? Is it M5X23MM?

Fits as advertised - easy to use

Familiarity:
I've put it through the wringer

Not a ton to write - the adapter is easy to install, true to size and easy to dial in, stays dialed in, and reasonably priced. It's very straightforward - kind of like getting an A on a first grade spelling test, but hey, it's an A.

Adapter, bolts and no washers.

Familiarity:
I've used it once or twice and have initial impressions

I ordered this to mount my Shimano M8020 caliper to my front fork paired with a 203mm rotor. The packaging includes the adapter, and 2 mounting bolts. BEWARE; no cup and cone washers are included. I feel that the washers should be included but understand they are not necessary. Wish they were more clear about what’s included in the packaging. 4 out of 5 starts because the washers should be included. The washers came with my rear adapters.

I am looking at the 160 to 203 post to post adapter. The photo of the part appears to be wrong. Will the part sent actually be a post to post adapter? The one shown is is to post. Thanks

Hi Mike- We unfortunately, don't have a picture for each one but the dropdown will be correct for the one you are wanting!

203mm brakes on RM Instinct

I loved my X2's with 180mm rotors, but I wanted more braking power without spending $500+ dollars for 4-piston brakes. So I did what a lot of people do in my situation and bought big ol' rotors and some adapters. For $100, I picked up rotors and adapters and I now have a noticeable increase in power while keeping the brake set I love. As others have said, the part numbers are very confusing, so hopefully these photos will clarify what's needed for 160mm and 180mm post mount applications. Sidenote: I was advised to avoid the Hope 203mm two-piece rotors on the Fox 34 due to clearance issues. I'm glad I chose the one-piece. It's a very tight fit but they clear, and they're about $15 less. Stoked!

I

Shimano brake adapter 180 to 203

Part # SM-MA-F203 (180mm to 203mm), Post/Post Front/Rear Hope X2 brakes with 203mm Hope one-piece rotors onto my Rocky Mountain Instinct (180mm post mount).

Part

Shimano brake disc adapter 160 to 203

Part # SM-MA-F203 (160mm to 203mm), Post/Post Front/Rear Mounted Hope X2 brakes with Hope one-piece 203 rotors on my Fox 34 (160mm post mount ) fork. I recommend one-piece rotors on the Fox 34 to avoid clearance issues. It's a tight fit.

Part

looking for front fork Post mount to Flat claiper, 160mm Center lock disc adaptor, for 2015 Cannondale 12

Perfect.

Familiarity:
I've used it several times

Got some to make my ripmo 203 F/R. Some pictures don't actually match what you're getting.

Works with SRAM Guides

Familiarity:
I've put it through the wringer

Used this for a hardtail build. The profile worked well with the shape of the SRAM Guide RSC calipers.

As Expected

Familiarity:
I've put it through the wringer

Does its thing and does it well. No complaints for this here.

What is the purpose of the little plastic clips that come with the mounting hardware?

Since asking this question I found the answer in a Shimano service manual. For anyone curious, the little plastic clips are supposed to be attached to the bolts after they are tightened to prevent them from loosening over time. The bolts come with thread lock already applied so the clips don't really seem necessary, and that explains why everyone gets by just fine not knowing what they are for.

Part works great, Part #'s not so much

Familiarity:
I've put it through the wringer

If you need it you need it. Simple adapter to hook it up. Hit us up if you have any questions on the application for your bike.

For forks with 180mm mounts

My fork has 160mm mounts so this one doesn't work for using a 203mm rotor.

A must.

Shimano's part numbers can be confusing. Be sure to hit the "Chat Now" button to get help from a Gearhead who can help confirm the correct adapter for your frame.

good luck!!

Familiarity:
I've used it several times

work great if you can figure out shimanos part numbers and fitment!!!....wooo hoooo!

Necessary

Familiarity:
I've put it through the wringer

Great little adapters to ensure that your brakes fit your bike.

Required parts

Familiarity:
I've put it through the wringer

If you want to follow the trend of having a 180mm rotor for the rear brake, you will need this if you have a Santa Cruz or any other brand that uses an international standard brake mount.