Adapters for Shimano BR-R785 calipers on flat mount frame/fork?

[NHAero]

Has anyone adapted post mount calipers to flat mount frame/fork? I see a TRP adapter at Competitive Cyclist - do these work well?

[prototoast]

On the fork, everything should work fine. On the frame, there isn't always enough room between the chainstay and seatstay to fit the adapter and caliper.

[NHAero]

Very helpful. Is there more likelihood of enough space on a large frame? This is for a big Diverge. Thanks!

Originally Posted by prototoast

On the fork, everything should work fine. On the frame, there isn't always enough room between the chainstay and seatstay to fit the adapter and caliper.

[yinzerniner]

Originally Posted by NHAero

Very helpful. Is there more likelihood of enough space on a large frame? This is for a big Diverge. Thanks!

You really have to measure it yourself since the rear triangle differs so much between bike to bike

Since the diverge is flat mount you might be better off purchasing flat mount 105 level calipers instead of faffing with adapters that may or may not work. This company in Canada has measurements that can tell you if their adapter will work, can’t see it being that much different than the specs needed on the trp adapters

https://www.assolutions.ca/shop/adap...ith-140-rotor/

[prototoast]

Originally Posted by NHAero

Very helpful. Is there more likelihood of enough space on a large frame? This is for a big Diverge. Thanks!

All things being equal, yes more likelihood it will fit on a large frame, but still hard to tell without doing a test fit. The Diverges use a sloping top tube and dropped seatstay, so even on the larger sizes, the angle at the rear dropout isn't that big.

For $12, it's probably worth the risk of trying the adapter, but I wouldn't bleed the brakes or run internal hydro lines until I was sure everything fit.

[NHAero]

It looks as though the assolutions adapter is to put flat mount calipers on a post mount frame, and I'm seeking the opposite.

My interest is that I'm passing my ST-RS685 shifters and BR-R785 calipers on to a friend as a set. The TRP adapters are $12 each, plus since this is a take-off, we know the hoses and fittings all match.

Originally Posted by yinzerniner

You really have to measure it yourself since the rear triangle differs so much between bike to bike

Since the diverge is flat mount you might be better off purchasing flat mount 105 level calipers instead of faffing with adapters that may or may not work. This company in Canada has measurements that can tell you if their adapter will work, can’t see it being that much different than the specs needed on the trp adapters

https://www.assolutions.ca/shop/adap...ith-140-rotor/

[unterhausen]

Shorter chainstays, taller frame, and horizontal top tube are all factors that would give you more room for brake calipers. There are rear adapters that drop the front of the caliper quite a bit. That should move the caliper forward too. I would shop around.

[yinzerniner]

Originally Posted by NHAero

It looks as though the assolutions adapter is to put flat mount calipers on a post mount frame, and I'm seeking the opposite.

My interest is that I'm passing my ST-RS685 shifters and BR-R785 calipers on to a friend as a set. The TRP adapters are $12 each, plus since this is a take-off, we know the hoses and fittings all match.

Ahh got yah. Yeah post mount calipers to flat mount frame / fork is almost always going to work ok. On the rear youd just have to make sure that the flat mount holes are fully off plane/ inside from the seatstay. See pic here for illustration of how adapter needs to clear the stag and the hub

https://www.mtbr.com/threads/help-me.../post-13915792

Diverge looks like it has plenty of clearance otherwise
https://www.cxmagazine.com/bike-revi...l-future-shock