Author Topic: disc brake flat mount facing tool  (Read 17958 times)

gribs

Re: disc brake flat mount facing tool
« Reply #15 on: July 18, 2026, 06:36:13 AM »
It got a review by someone I follow on Youtube and it seems very positive.

youtube.com/watch?v=RYmu2zBefWQ
« Last Edit: July 18, 2026, 06:38:13 AM by gribs »

Sand101

Re: disc brake flat mount facing tool
« Reply #16 on: August 01, 2026, 05:33:40 PM »
It got a review by someone I follow on Youtube and it seems very positive.

youtube.com/watch?v=RYmu2zBefWQ

After seeing this video (had no idea this tool existed) I gave it a shot for $65.  I have three disc brake bikes in the house - my GR201 gravel bike, R088 roadie, and my wife's Liv aluminum gravel bike.   I have spent a ton of time on all three trying to get these to not rub, with mixed success and a lot of cursing.  Got this tool in, set this up and went to it.  All three bikes had the front well out - the back on all three was ok.  The improvement was massive; the front brakes are now dead straight.  Totally worth the money.   

As with these kind of instruments that make irreparable changes the key is to take the minimum off - I marked the surface to be machined (as in the video) and took the minimum off.  The minimum being 75% flat surface or so.  Went slow, checked often with no pressure other than the light spring (which was more than enough to remove material).  It did not take long to remove what needed to go.

Big thumbs up on this tool.

jermu

Re: disc brake flat mount facing tool
« Reply #17 on: August 14, 2026, 02:03:38 PM »
Tried this on my VeloBuild aero gravel and it works well, there is some very minor play between the interface on the final part between the grinding disc and the arm. Apart from that so far so good.
Faced mounts so far with a simple file and trying the caliper on which quite a bit of time because you are constantly taking off the caliper.

My procedure with file facing is: have the wheel on with the disc, mount caliper WITHOUT the brake pads and tighten either bolt and see what happens between caliper and the disc and then file to opposite direction.

With this it just seems simpler.

Facing with a file I get to "good enough" and with this while not perfection I get most the way there.

Bonus points that my VeloBuild front thru axle does not fit to the front axle fitting lol, tried TanTan thru axle and it works.

00Garza

Re: disc brake flat mount facing tool
« Reply #18 on: August 20, 2026, 09:42:35 AM »
This popped up in my feed. A bit pricey.
 
I just found this on AliExpress:  | LEBYCLE Bike Disc Brake Mount Facing Tool For Flat/Post/IS Mount Quick Release andThru Axle Bike Frame Disc Brake Base Repair Tool
https://a.aliexpress.com/_mqndFM3

Dan S.

Re: disc brake flat mount facing tool
« Reply #19 on: August 21, 2026, 02:51:42 AM »
This popped up in my feed. A bit pricey.
 
I just found this on AliExpress:  | LEBYCLE Bike Disc Brake Mount Facing Tool For Flat/Post/IS Mount Quick Release andThru Axle Bike Frame Disc Brake Base Repair Tool
https://a.aliexpress.com/_mqndFM3

That’s almost as expensive as the ParkTool one.

frewster

Re: disc brake flat mount facing tool
« Reply #20 on: September 15, 2026, 10:19:17 AM »
After seeing this video (had no idea this tool existed) I gave it a shot for $65.  I have three disc brake bikes in the house - my GR201 gravel bike, R088 roadie, and my wife's Liv aluminum gravel bike.   I have spent a ton of time on all three trying to get these to not rub, with mixed success and a lot of cursing.  Got this tool in, set this up and went to it.  All three bikes had the front well out - the back on all three was ok.  The improvement was massive; the front brakes are now dead straight.  Totally worth the money.   

As with these kind of instruments that make irreparable changes the key is to take the minimum off - I marked the surface to be machined (as in the video) and took the minimum off.  The minimum being 75% flat surface or so.  Went slow, checked often with no pressure other than the light spring (which was more than enough to remove material).  It did not take long to remove what needed to go.

Big thumbs up on this tool.

I had the same experience. Threaded inserts were proud (not flush) with the mounting posts on the fork of my FM336 and it was impossible to tighten down the caliper without it shifting and rubbing the disc. Carefully used this facing tool (by hand, not with a drill) and I was able to grind down the threaded inserts until I could drag my fingernail across the surface without it catching on anything.

One recommendation from my experience: position the disc so it faces both mounting posts at the same time and press the disc firmly against the mounting post surfaces while tightening the mounting bolts to ensure it is making as flush as possible contact with both at once.

dyed

Re: disc brake flat mount facing tool
« Reply #21 on: Today at 03:36:48 PM »
The tool seems to be pretty well made, the disc itself is very sturdy and flat. the axle adapters are nicely machined and everything tightens up well, no play. Other than using a metal file, this is my first attempt at facing the mounts to try and get rid of a noisy/vibrating front brake and I don't necessarily know the mount is misaligned in the first place. Certainly, putting the facing disk up against the mounts, they look pretty flat. But using the tool is pretty simple, the spring provides enough pressure that you can just turn it and it starts taking aluminium off.


I bought one on a lark, and my take is that it's a piece of garbage, and not any better than I can do with a hand file.

The alignment of the main structure is fine, but the myriad axle adapters leave a lot to be desired and allow too much slop. Worse, the cutting disc isn't supported on the back side, and flexes easily. If you put any pressure on it at all, you won't have a flat, true surface.

Neat idea, needs a lot of work.

Tijoe

Re: disc brake flat mount facing tool
« Reply #22 on: Today at 04:42:48 PM »
Back in the Aliexpress SPCycle M05 dark ages,  (about 3 years ago).   When I built my bike, I had to carefully remove the paint off of the frame's caliper mounts.  - Combination of chipping off the paint, a file and sanding.   I originally mounted a 160 rear rotor, and didn't pay any attention to where the rotor sat relative to the caliper pads.  Turns out, as the pads wore, the rotor was not flush with the top of the pads.  I migrated to a 180 rotor and used an adapter between the frame and the caliper. I used my mill to remove about 1.5mm from the adapter so the the OD of the rotor was flush with the top of the the pads.  As the new pads wore, I noticed they were wearing at an angle.  I had never really paid any attention that the mounts wouldn't be perpendicular to the rotors.   No big deal, the rotor wasn't rubbing on the pads.

Then I migrated to 203mm rotors, front and back, and the lack of perpendicularity of the caliper came back to haunt me.  I very carefully used a file and then a polishing disc to get the caliper and adapter to be perpendicular to the 203mm rotor. 
All has been well since.   

I didn't start seeing ads for flat mount facing tool until earlier this year.  It would be nice to have one, but I have the ability to manually  fix the mounts if necessary so one has not been on my purchase short list.