Flat to Post mount brake adaptors?

Wrath Rob

Hi all, I'm looking to buy some Shimano 505 (or similar) brakes as part of an upgrade to 11 speed. Does anyone know if you can get rear flat mount to post mount adaptors? I've seen them for front callipers but not anything for rears. Unless I can find some its going to kill my plans to upgrade.

Otherwise I'll either have to do the mech/hydraulic option or get the whole rear triangle rebuilt to take flat mounts! Its actually more of an option that you think as its a titanium bike and I'd like to move the calliper mount to the chain stays instead of the seat stays. The advantage of a custom built frame

nicklouse

what do you mean by FLAT mounts?

there is the IS or Post.

and there is very little that can not be mounted to one or the other.

what has your frame got? pics if not sure. or frame info.

nicklouse

at a guess as the Shimano 505 calipers are Post mount I would say you have IS mounts in the frame.

Note the IS rear is 20mm less in diameter for rotor size.

so a 180 adaptor for the front is 160 rear.

Wrath Rob

See these, the R505: https://www.merlincycles.com/shimano-10 ... 0wod7vwIJQ

The callipers are part of the Shimano flat mount standard.

I have Avid BB7s on the on the bike right now which I understand are pre-Shimano flat mount standard. However, I could be wrong! The bike is 3 years old.

Finally, looking at the Shimano standard, my bike doesn't have a bolt in the chain stay, its all in the seat stay.

Therefore I believe my bike is not flat mount compatible and I therefore need an adaptor. However, I can't find one online, so I'm probably looking in the wrong place or for the wrong thing!

nicklouse

depending on the frame fitting it looks like you can do it either way.

cant find any tech standards (no looked too hard) but it looks like it is designed to have the same size rotors front an rear.

front mounting looks like a reduced post mount so gives 140 disc use when mounted.

so if fitted to a post mount (presuming same bolt spacing etc) should require a 160mm disc.

frame if post mount use the front mount and a 140 disc . if IS mount then still use the front mount and then an IS to post adaptor but you will need a 160 disc.

that is from a few moments of looking.

needs more info to be 100% accurate.

I know what I would be tempted to do. chat with the frame builder.

Wrath Rob

nicklouse wrote:

I know what I would be tempted to do. chat with the frame builder.

Already doing that too

I'm asking him about rebuilding the rear triangle to move the mount point to the chainstay to make a neater installation. Having them on the seat stay is a pain as I run mudguards.