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Discussion Starter · #1 ·
2019 Trek Slash 9.8, came with Guide RS brakes, 200mm front rotor, 180 rear. I want to upgrade the rear to 200 but can't find information on which adapter to use.

Anyone know what I need?

Thanks!
 

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Discussion Starter · #3 ·
The Slash uses post mount in the rear, which means you'll need a post to post adapter. It looks like it already has an adapter (can you confirm that?), so the frame is designed for 160mm and has an adapter to use 180mm. Therefore you'll need to replace that adapter with a 40mm post to post.

https://www.artscyclery.com/keeping-the-rubber-side-down/rubber-side-down-disc-brake-adapters/
Yup, it has an adapter on the back that measures 14mm high on the front, and 8mm high on the back. So would I need am adapter that is 20mm taller? Or is it not that simple?
 

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Yup, it has an adapter on the back that measures 14mm high on the front, and 8mm high on the back.
That would be a 20mm adapter. (180m rotor on 160mm post mount)

So would I need am adapter that is 20mm taller?
Nope

Or is it not that simple?
Yep.

You will need a 40mm post adapter.

https://www.jensonusa.com/SramAvid-Disc-Post-Bracket

* 40mm post adapter on 140mm post mounts = 180mm rotor
* 40mm post adapter on 160mm post mounts = 200mm rotor
 

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You'll need another set of the shorter SRAM anchor bolts, too. The ones sized to mount the caliper directly to the frame. The adapter comes with one pair, but assumes you have one set in hand already.

To clarify, direct mount uses short bolts. 20mm post adapter uses the long bolts. 40mm uses two sets of short, one to mount the adapter to the frame, one to mount caliper to adapter. See the pic below of how my front caliper is mounted.


Sent from my Pixel 2 using Tapatalk
 

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Discussion Starter · #7 ·
You'll need another set of the shorter SRAM anchor bolts, too. The ones sized to mount the caliper directly to the frame. The adapter comes with one pair, but assumes you have one set in hand already.

To clarify, direct mount uses short bolts. 20mm post adapter uses the long bolts. 40mm uses two sets of short, one to mount the adapter to the frame, one to mount caliper to adapter. See the pic below of how my front caliper is mounted.


Sent from my Pixel 2 using Tapatalk
Perfect, I actually should have an extra set of short bolts here from another bike.
 
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