Author Topic: Disk brake adapters  (Read 541 times)


  • Mostly Harmless
Disk brake adapters
« on: January 19, 2020, 08:24:30 pm »

My bike has 51mm ISO disk brake mounts, mounted to which I have PM adaptors, to allow me to use 74mm post mount calipers. I notice that increasingly PM calipers are being replaced with Flat mount. Can I use flat mount on my bike if I put an FM to PM adaptor plate onto the PM to ISO adaptor? Or do ISO to FM adaptors exist?


Beer, bikes, and backpacking

Re: Disk brake adapters
« Reply #1 on: January 19, 2020, 08:47:59 pm »
Technically post mount to flat mount adapters shouldn’t exist, because it would need a negative height spacer to mount the calliper according to spec. The ones that do exist only work with certain callipers and certain post designs because they wedge the calliper into the gap between the posts.

There’s absolutely no reason to though. The only advantage of FM is a neater more aero look, and if you’re docking  about with adapters you lose that.


  • rothair gasta
Re: Disk brake adapters
« Reply #2 on: January 19, 2020, 08:49:26 pm »
Flat mount brake to IS adapter available here.
Check the details for whether it will fit on your frame/forks.
That seems to be the only one available so far. Not cheap, with postage costs and import taxes etc. Not sure if there is any European distributor.