Fitting Hope Disc brakes to a C60

[Ballistic]

I have a Colnago C60 that currently has Shimano Ultegra Di2 BR-RS805 calipers and 140mm rotors front & rear, and I'm looking to change them both for a Hope setup, basically to eradicate the horrendous brake squeal and almost none existent retardation that I'm experiencing with the Ultegra brakes.

I spoke to the Hope dealer to discuss my requirements and ask them if I will need any specific mounting adaptors. The order has been a real cock-up; when I placed the order they had two calipers in stock in the colour I wanted (Orange) and shortly after I was told they only had one left and credited me for the other.

Yesterday I received one orange RX4-SH postmount front caliper, which as it turns out isn't a direct swap for the BR-RS805, that I hoped it would be.

From looking at the diagrams on the enclosed instructions it would appear that the caliper I need is a RX4-SH front flat mount, which is designed to go with a 160mm rotor.

So my options seem to be;
1) Get a caliper mounting adaptor for the RX4-SH front postmount caliper that I have - Hope offer a bewildering choice of mounting adaptors and it isn't crystal clear to me as to which one I will need and the dealer seems incapable of advising me.
2) Return the RX4-SH front postmount caliper for a credit and find someone who has in stock front and rear orange flat mount RX4-SH calipers and 160mm centre lock rotors.

Which option would you choose and why?

I really want to get this sorted ASAP as I can't ride the bike.

TIA

Edited by Ballistic on Friday 9th April 09:59

[wobert]

My recommendation would be to return what you’ve had delivered and resource the correct flat mount callipers.

PM to FM adapters do exist, but they are expensive and look crap.

https://www.assolutions.ca/flat-mount-caliper-to-p...

I had the same issue on a gravel bike I was converting to full hydros, I had the opposite problem, FM callipers going onto a PM frame.

To cut a long story short, I sold the FM callipers on and bought some post mounts instead.

[snotrag]

Just buy the right bits, you've got the wrong stuff. I presume the Colnago C60 has flat mount brakes front and rear.
Hope RX4 only work with 160mm rotors for a start - so you need 2x 160mm rotors. The you need two, RX$, Shimano, Flat mount calipers. In whatever colour you want.


However:

Ballistic said:

horrendous brake squeal and almost none existent retardation that I'm experiencing with the Ultegra brakes.

The actualy problem you have is that you have the infamour Shimano Caliper leaky seals. Fixing this would fix the issue - Ultegra calipers are fine when working properly. There are aftermarket pistons and seals available to suit.


I ran RX4 on my Gravel bike and they are brilliant but not the only solution.

[Ballistic]

Many thanks for the advice received so far.

I thought that replacing the brakes would be a simple and straightforward task.

snotrag - now you've got me thinking; I'll try and source a caliper overhaul kit for the Ultegra brakes and see if this fixes the issue.

[numtumfutunch]

Ballistic said:

snotrag - now you've got me thinking; I'll try and source a caliper overhaul kit for the Ultegra brakes and see if this fixes the issue.

Ive run 105 on my commuter/winter bike for 5 years and have no issues with them

They're perfectly fine, squeal occasionally admittedly, but have essentially been fit and forget besides new pads

Now youve got me thinking I havent ever had to bleed them let alone change the fluid

Good luck

[Ballistic]

snotrag said:

Ultegra calipers are fine when working properly. There are aftermarket pistons and seals available to suit.

Do you know where I can obtain these spares from - a Google search isn't bringing anything up?

[frisbee]

Ballistic said:

snotrag said:

Ultegra calipers are fine when working properly. There are aftermarket pistons and seals available to suit.

Do you know where I can obtain these spares from - a Google search isn't bringing anything up?

When I half looked at rebuilding mine (earlier post mount ones) there were some crappy looking pistons and seals on ebay, shipped from China, for about £15/calliper.

I figured for safety and also that I could get a replacement calliper with pads for £30 that it wasn't worth the effort.

Touch wood, both replacement callipers have been fine. Although one gave the impression of failing but it turned out to be a tiny leak from the hose connection which was solved by wanging it up tighter.

Sets of lightly used Hope ones do show up on ebay quite often.