Any experienced hope rx4 users?

[Retiredtester]

Having picked up a 2nd hand partial grx group set, I'm in the process of replacing the SRAM rival set up on my gravel bike - neither the brakes nor gears have ever worked particularly well, due in no small part to my lack of mechanical nous. The brakes in particular have always been crap. I've tried bleeding several times and doing the piston extension (without pads) trick, but there is still a huge amount of lever throw and the pads always rub.

My frame has post mounts and luckily the previous grx owner has replaced the flat mount calipers with Clarks post mount. I'm going to give the Clarks a go, but am hope rx4 curious. As with everything there seem to be a lot of conflicting opinions on these and I just wondered if there were are long term users on here who might offer their opinions? In particular, are they especially tricky to bleed and set up, and do you get a lot of pad rub? Also interested if anyone else has tried the grx Clarks combo.

Thanks in advance and happy new year!

[Hyppy]

I'm a long term user of both RX4 and RX4+ calipers albeit the DOT/SRAM version rather than mineral/Shimano.

Initial bleeding when installing was a bit of a pain, but once done is done and they perform admirably. I have had problems with pistons sticking every so often when ridden in crappy conditions, but a thorough clean and dab of grease has always sorted it out post-ride. It's certainly something to be prepared for though, as I've finished a couple of longer rides with them binding, most recently the BB200.

They seem less prone to rub in normal use than SRAM calipers do, but I'm not sure that's much of an endorsement!

[Retiredtester]

Thanks very much Hyppy, that's really useful. I've since discovered post mount frame to flat mount caliper adapters at a reasonable price on Amazon, so I may be able to use grx or ultra FM calipers as an alternative. That said, I've experienced the leaky piston Shimano curse, so I might swerve them....

[Lazarus]

I think i have a front post to flat mount adapter if you want it almost certainly 160mm

[Retiredtester]

Thanks Lazarus. I'll drop you a line.

[substandard]

Rx4s were a royal main the arse for me, had two sets on two different bikes and had the same issues with both.

The piston bores are tiny and were forever sticking, fully stripped down multiple times and relubed using the hunter silicon stuff they recommend only to end up back sticking again in no time.

Flogged them as spares or repairs and went back to seam calipers which are ‘less crap’ than my rx4 experiences!

Other hope calipers have never given me issue on mtbs

[Retiredtester]

Rx4s were a royal main the arse for me, had two sets on two different bikes and had the same issues with both.

The piston bores are tiny and were forever sticking, fully stripped down multiple times and relubed using the hunter silicon stuff they recommend only to end up back sticking again in no time.

Flogged them as spares or repairs and went back to seam calipers which are ‘less crap’ than my rx4 experiences!

Other hope calipers have never given me issue on mtbs

Thanks for that. This is something I've seen in other long term reviews. I think I'll give them a miss and see how the Clarks behave. If they're no good (I have very low standards tbh) then I might try some Shimano 4 pot MTB calipers. Thanks all

[Hyppy]

FWIW, I've had less problems with pistons sticking with the RX4+ than I did the RX4 version. Evidently an issue though, regardless.

[Retiredtester]

Thanks hyppy

[substandard]

Mine were both the original rx4 versions rather than plus. Plus has bigger pistons but I was so off put by the issues I’ve given them a wide berth.