SRAM AXS Flat-mount on post mount frame

[Mustangski]

Good afternoon Paceliners,
I’m riding a Ritchey Outback, V1 so it’s made for post mount brakes. I run Rival 1 w/ TRP Spyre-C’s on it and jumped at the chance to get back into SRAM AXS hydro recently not realizing that all AXS is flat-mount.

I found the below Wolftooth adapters which state they require an increase in rotor size by 20mm. I can’t find details on the V1 Outback and what size rotors the post-mount is made for. The V2 is 140mm and can handle up to 160 according to the Ritchey website.

https://www.wolftoothcomponents.com/products/post-to-flat-mount-brake-adapter

My current setup has the Spyre-C’s going to 160 rotors with no adapters/spacers. Anyone running a Ritchey Outback with AXS? Or know what size rotors the post mount was made for on the V1? If it’s 160, I may need to look at putting the Spyre’s back on and keep this for the next frame.

[KonaSS]

If you are currently running 160s with no spacer/adapter, than that is your answer. You wouldn't be able to run a 140 on this bike.

[p nut]

I’m about to do something similar with a dropbar mtb set up.

Per tech support, you are able to use their Line calipers. I’m unsure of the advantage/disadvantage of going one way or the other.

[Overshot]

On a similar drop bar MTB setup I found some red post mount calipers and used those. Works perfect.

[kppolich]

I have RED AXS Post mount calipers that I will be listing soon.
Not 'all' axs is post mount, they just use the previous version 1 piece caliper post mount brakes.

[Mustangski]

I was hoping to use the SRAM Rival calipers that came with it, the adapters look like they'll work however may need to run a larger rotor. The adapters require a rotor 20mm larger than the stock configuration for post mount.

Anyone running 180's on a Ritchey?

[Mustangski]

Wanted to post some solutions for future searchers.

I've found two company's that make post-mount to flat-mount adapters, both are similar with slight differences.

Wolftooth makes the below adapters, however they do require a +20mm increase in the factory rotor size. So basically if your frame was made for 160mm, which mine was, you need to run 180mm rotors for these to work.

https://www.wolftoothcomponents.com/products/post-to-flat-mount-brake-adapter

Next is a Canadian company called AS Solutions, they make adapters that don't require the rotor increase.

https://www.assolutions.ca/flat-mount-caliper-to-post-mount-adapter-guide/

I already purchased the Wolftooth version, but not sure I want to run 180mm rotors on my bike. That seems huge for a gravel/road build, but haven't decided yet.

[Alistair]

If you have the clearance to run the AS Solutions adapter, that's the way I'd go. But, it dose require quite a bit more space (24mm from frame surface to top of posts vs 13mm for the WT version).

180mm on a road bike seems like overkill. I'm assuming the Outback is 160mm fork and frame? The WT version would be great on a mountain bike where forks and frames are often built for 160 PM, but delivered with 180-200 rotors (with adapters).

[EB]

I thought AXS hydro calipers were available in post-mount, like this: https://www.modernbike.com/sram-red-axs-post-mount-mount-disc-brake-caliper

If not, there's also these: https://www.hopetech.com/products/brakes/road/rx4-caliper/

Long live post mount - I have come to grudgingly accept flat mount, but I will never think it's a good standard.

[Mustangski]

I would love to use the Hope RX4+ calipers, just can't seem to find any available right now.

I was told that the SRAM Level calipers will work, but they didn't mention the SRAM Red post mount calipers. I'll have to check it out and see if they would work, can't imagine why they wouldn't.

If you have the clearance to run the AS Solutions adapter, that's the way I'd go. But, it dose require quite a bit more space (24mm from frame surface to top of posts vs 13mm for the WT version).

180mm on a road bike seems like overkill. I'm assuming the Outback is 160mm fork and frame? The WT version would be great on a mountain bike where forks and frames are often built for 160 PM, but delivered with 180-200 rotors (with adapters).

I've messaged AS Solutions to see when they will be back in stock, the Outback V1 is made for a 160mm rotor.