Issues with GRX brakes - anyone moved to RX4+ calipers ?

[d8mok]

I’ve been running GRX810 on my gravel bike for coming up to 2 years now.

It’s my favourite bike and gets used the most but has suffered bad brake contamination for the past year maybe on and off.

For some reason the brakes get contaminated every so often and it requires new pads and cleaning of the rotors. This has slowly gotten worse to the last 2-3 months where the back brake is non existent and the front is awful.

I’ve tried IPA , brake cleaner, cooking the pads , new pads , lots of heat via blowtorch , and it sorts the issue for a bit but then it comes back.

I read online that it could be the calipers leaking a small amount of fluid onto the pads and this is just a quirk of Shimano. This sounds like it could be my issue.

So to my question , has anyone used Hope RX4+ calipers mated with GRX levers ? How easy to mate them and also how well so they work. I’d be buying new Hope discs too.

 

[biggins]

Can't answer the question about the RX4+ calipers, but share your pain trying to fight contaminated rotors and pads for 18 months. Even looked for evidence of piston seals leaking, took ages enough for it to be enough to be evident. Drove me to the point that even though I changed brakes now I am still paranoid about rotor contamination

 

[d8mok]

Thanks for response. What brakes was that on? Seems Shimano is known for it.

I’ve cleaned my brakes with IPA, put new pads and cleaned the rotors. They now work very very well. However I’ve only ridden it on my road and I’ve been here maybe 10 times with working brakes but Once I’ve ridden it, it will deteriorate again to no brakes I just know it. Water seems to make it lots worse as I guess it circulates any contamination

 

[frank.youngman]

I went to RX4 from SRAM Force on my gravel bike due to a complete inability to stop brake squeal.

The calipers work better than Force and have eliminated most of the brake squeal,however the big advantage is that they can be rebuilt as required and spares are available from Hope.

 

[d8mok]

Did you bleed them yourself as I’ve read stories they are awkward to bleed and the smaller pistons sometimes get stuck ?

 

[wynne]

Put rx4s on my Sram Force brakes too.
Have raced (including 3 peaks cx) and toured fully loaded on them. Even on the steepest descents i can bring myself to a quick halt with just one finger. Haven't had to touch them since i installed them 3 years ago, with exception of changing pads. Can't prsise them highly enough.

 

[d8mok]

I’m a big fan of Hope brakes so I’m going to give the GRX a final chance when I ride it next but if they end up bad again I’ll order some. Are you running Hope centrelock rotors?

 

[biggins]

Thanks for response. What brakes was that on? Seems Shimano is known for it.

I’ve cleaned my brakes with IPA, put new pads and cleaned the rotors. They now work very very well. However I’ve only ridden it on my road and I’ve been here maybe 10 times with working brakes but Once I’ve ridden it, it will deteriorate again to no brakes I just know it. Water seems to make it lots worse as I guess it circulates any contamination

They were Shimano. Like you they deteriorated, so I assumed some over spray in shed, cleaned rotors and pads, they would improve then deteriorate again over time. They would improve over a ride so I would think I had sorted it. Changed rotors and pads, ended up the same. Even put tissue in between pads and pistons and squeezed levers hard as was suspecting piston seals. No evidence on tissue. In the end left it with out washing between rides to let any leaked fluid to build up, did 4 or 5 rides, pulled pads out and saw the damp piston shaped ring on the back. My thinking is at first the contamination was so slight that with the heat and surface wear on a ride they would improve, never great but improved.

 

[d8mok]

Makes me happy in a weird way that I’m not going crazy and it’s happened to someone else. Cheers

 

[jonnyboy666]

shop mechanic opinion,

in the last couple of years i have seen more leaking calipers from shimano, not loads, but it's more common than a few years ago. regards GRX, i haven't had any problems as such with any i have sen in the shop but my gravel set up is running grx levers with ultegra calipers, and as i had them in stock i used Aztec rotors, now i got a bit paranoid that i had contaminated something as they make squealing noise at low speed, but when in use generally they are fine, the power also seems fine.

regards the hope calipers, i've sold a few sets, all customers have been happy with the feel and the power regardless of whether they were for sram or shimano, definitely a massive improvement over sram though, better rotor clearance, more solid feeling at the lever, shimano feel the same but a bit more power i'd say.