Flat mount discs and steel chainstays

[mmoore]

Yes, it was likely conceived for rear brakes, but I do admit that it looks cleaner on the front too, with the proper fork. now we need to wait for the market to catch up and provide a nice FM, thru axle disc fork with clearance for 35c's.

[EricKeller]

now we need to wait for the market to catch up and provide a nice FM, thru axle disc fork with clearance for 35c's.

umm...what? That looks like it would be a lot easier to build a steel fork for than post mount, which sticks way out back. Now I'm actually motivated to look into it.

[mmoore]

umm...what? That looks like it would be a lot easier to build a steel fork for than post mount, which sticks way out back. Now I'm actually motivated to look into it.

There are no aftermarket flat mount forks that Im aware of, yet. Something like the Enve GRD, yet to be released, with flat mount disc would be great.

[EricKeller]

I know that, I'm just saying this is the frame builders section, forks are part of the frame. You will never convince me otherwise.

[mmoore]

I didn't say anything to that effect.
find me a carbon flat mount fork that you can buy that isn't attached to a bike and I will build around it.

building a fork is a whole different thing.

[incepi]

building a fork is a whole different thing.

Building a fork for flat mount may not always be straightforward. The reason for this is that the front mounts are located very close to the axle centerline. 11mm is the offset. The fork leg diameter has to be limited(not ideal for dealing with disc braking forces), or bent and flattened to bring the tube into position. If the leg is 22mm diameter or less(and centered on the axle) it will probably not be an issue.

tech_details_roadhouse3.jpg

[incepi]

There are no aftermarket flat mount forks that Im aware of, yet.

Here is one. They accept western union too.

2016 Carbon Fork Road,Disc Flat Mount,Through Axle,TR-FK071CF, View carbon fork road disc flat mount, OEM Product Details from ArchTeks Tech Co., Limited on Alibaba.com

[Gattonero]

Yes, it was likely conceived for rear brakes, but I do admit that it looks cleaner on the front too, with the proper fork. now we need to wait for the market to catch up and provide a nice FM, thru axle disc fork with clearance for 35c's.

PM looks neat too, but the problem raised and the introduction of this new standard is to avoid threaded inserts in the carbon frame. As far as carbon forks, whether you have FM or PM there is still a threaded instert bonded in the frame; and if you ask me, in beteween the two devils, I will always have a locked rear rear but never want a jammed caliper in the front one!

Again, unless I'm missing something, FM could work on steel forks, not on carbon ones as it doesn't solve any problems at all.
This FM thing seems it just creates more SKU's and stock to keep.

Building a fork for flat mount may not always be straightforward. The reason for this is that the front mounts are located very close to the axle centerline. 11mm is the offset. The fork leg diameter has to be limited(not ideal for dealing with disc braking forces), or bent and flattened to bring the tube into position. If the leg is 22mm diameter or less(and centered on the axle) it will probably not be an issue.

tech_details_roadhouse3.jpg

You got it man, attaching more things where the forks are likely to have a smaller diameter, is it a good idea?

[EricKeller]

I'm waiting for the first flat mount to post mount adapter.
I would think that flat mount forks will be 12mm TA, which looks like it will clear the bottom insert just fine. There are threaded inserts in current carbon forks. While it might not be ideal, I'm not sure it can be avoided

[EnginCycles]

I'm waiting for the first flat mount to post mount adapter.
I would think that flat mount forks will be 12mm TA, which looks like it will clear the bottom insert just fine. There are threaded inserts in current carbon forks. While it might not be ideal, I'm not sure it can be avoided

[EricKeller]

Thanks Drew, I saw those and it didn't sink in

[Broady]

[mmoore]

how much of a pain was it to set up?

Looks like a good amount of the chainstay needed to be mitered out. great execution.

[Broady]

Not actually my handywork (although it will be my frame). Ricky Feather is the fabricator. He said it was tricky, probably being the first, but I'm sure it's one of those jobs that gets easier once you've done a few!

[Will Neide]

That certainly looks clean!

Looks like it could easily get frustrating to build it into every frame.

[incepi]

Looks like it could easily get frustrating to build it into every frame.

A simple alternative is possible.

Install a vertical disc tab, similar to the traditional ISO mount. The hole center to hole center dimension does not have to be 51mm. Then fabricate an adapter for the 34mm flat mount caliper, where the caliper is bolted from below. The whole system could be similar to an ISO tab with a post mount adapter. It would raise the caliper above the chainstay slightly, but would be much easier to do than mitering the chainstay.

[EricKeller]

is the standard available online?

[Clockwork]

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[e.Gellie]

.......Have the flat mount shimano calipers made it to market yet?

Yes. The Shimano BR-RS805 is available from Shimano, here in Australia.