Hope RX4 Caliper

Discuss light weight issues concerning road bikes & parts.
justaute
Posts: 227
Joined: Fri Jan 04, 2013 7:17 pm
Location: UT/TX/PA, USA

by justaute

Anyone has experience with the new Hope caliper? I did a search and found several topics regarding their introduction, but no one seems to have used it.

I'm using the RS785 calipers on my cx/gravel/winter bike, but really don't like the drag and pingings. I have read that pistol retraction is an issue on the R/RS785 calipers. Exploring the options of using XTR caliper or these new RX4 caliper.

Thanks.

by Weenie


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MayhemSWE
Posts: 130
Joined: Thu Mar 12, 2015 12:44 pm
Location: Stockholm, Sweden

by MayhemSWE

Also very much interested to hear if anyone has picked these up yet. Though announced long ago I don't think they've been available to buy until pretty much now? At least I haven't seen them listed at any retailer until just now when Bike 24 says they can source the post mount versions from Hope in 5-8 days (flat mount versions not listed yet though). Personally I'm dealing with sticky pistons and pad clearance on a Rival equipped bike so my own interest is primarily in the Sram/DOT5.1 version…

MichaelB
Posts: 448
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

If you are already on the Shimano system and want a 4 pot Post mount caliper, go with the Zee. I have and they work great with the RS685 levers. Great lever feel and modulation.

I'd love to see how the RX4 calipers go too, but are they only the DOT fluid ? - Oh, just looked at the Bike24 blurb, and they are making them for each fluid type. Nice.

What piston sizes are they ?

Would they require a different hose/connectors to fit to the Shimano RS685 levers when compared to the R785 calipers (i.e. plug & play) ?

justaute
Posts: 227
Joined: Fri Jan 04, 2013 7:17 pm
Location: UT/TX/PA, USA

by justaute

This is weightweenies, no Zee/Saint calipers are allowed -- at least not on my gravel/allroad bike. :)

If I don't get any real feedback on the RX4, I'll probably just go with XTR M9020 calipers. ~103g each.

Broady
Posts: 279
Joined: Thu Jan 03, 2013 5:02 pm

by Broady

RX4 flatmount available soon apparently, I'll be getting as soon as available.

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MayhemSWE
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Joined: Thu Mar 12, 2015 12:44 pm
Location: Stockholm, Sweden

by MayhemSWE

MichaelB wrote:I'd love to see how the RX4 calipers go too, but are they only the DOT fluid ? - Oh, just looked at the Bike24 blurb, and they are making them for each fluid type. Nice.

What piston sizes are they ?

Would they require a different hose/connectors to fit to the Shimano RS685 levers when compared to the R785 calipers (i.e. plug & play) ?

Check out Hope's website, they have PDF's available for the instructions and parts diagrams:
http://www.hopetech.com/product/rx4-caliper/

Piston sizes are not listed anywhere but are different between the Shimano and Sram versions to compensate for different master cylinder sizes. Judging by the part numbers, the large piston on the Sram version is the same as the small piston on the Shimano version! As a consequence of this the size of the brake pads are also different.

From my understanding of the installation instructions you can keep the original hose but will need to cut it and install a new Hope fitting.

MichaelB
Posts: 448
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

@justaute - from a WW perspective, got it, but the Zee/RX4 weights are close - Zee Caliper (bare) : 127g ea, Shimano pads, springs & split pin : 24g (set - unfinned) & Uberbike pads, springs & split pin : 23g (set).

The RX4 Shimano version uses the Tech 3 E4 pads which are deeper (37 x 29mm) than the Zee pads (39.5 x 24.2), but slightly shorter, so matched there.

Couldn't work out the pad size for the SRAM version.

If the hose length is long enough, then it seems a pretty easy install if you want a 4 piston caliper !!

MichaelB
Posts: 448
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

Edit didn't work ...

I guess the other HUGE bonus, is that the spares are theoretically available !!

Just found the details on the piston diameters here. Note this is from 2012, so doesn't have latest calipers like Tech 3 E4.

SRAM verwsion uses 14 & 11mm (same as Mon 6 pistons), and Shimano version uses 16 & 14mm from Mono M4.

Interesting comparison, is that the Zee/Saint calipers use 18 & 16mm pistons, but they still work well with the RS685 levers !!

Hmmmm, something to play with in the future ?

justaute
Posts: 227
Joined: Fri Jan 04, 2013 7:17 pm
Location: UT/TX/PA, USA

by justaute

Thanks for all the information, MichaelB. Interesting stuff. Didn't think Zee would be that light.

To me, I don't need more power. I want better, more consistent piston retraction. My current RS785 is good enough as far as power goes, but retraction isn't good and they are heavy.


MichaelB wrote:@justaute - from a WW perspective, got it, but the Zee/RX4 weights are close - Zee Caliper (bare) : 127g ea, Shimano pads, springs & split pin : 24g (set - unfinned) & Uberbike pads, springs & split pin : 23g (set).

The RX4 Shimano version uses the Tech 3 E4 pads which are deeper (37 x 29mm) than the Zee pads (39.5 x 24.2), but slightly shorter, so matched there.

Couldn't work out the pad size for the SRAM version.

If the hose length is long enough, then it seems a pretty easy install if you want a 4 piston caliper !!

MichaelB
Posts: 448
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

NP. Have always found it hard to get info on the piston sizes.

BTW, the Hope Tech 3 E4 caliper uses 16mm pistons (x4), but is built for DOT fluid only.

Broady
Posts: 279
Joined: Thu Jan 03, 2013 5:02 pm

by Broady

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L3X
Posts: 290
Joined: Wed Feb 25, 2009 8:39 pm

by L3X

Do these only work with 160mm rotors?

justaute
Posts: 227
Joined: Fri Jan 04, 2013 7:17 pm
Location: UT/TX/PA, USA

by justaute

For flat-mount, that's the case.


L3X wrote:Do these only work with 160mm rotors?

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wheelsONfire
Posts: 1849
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

Postmount does also work with 160mm Rotors.
Agree with you justaute, they don't retract as well as i would like, but braking power is clearly sufficent for hard ass gravel.
It's way to easy to get pad rub and when changing wheels i often need to adjust the calipers.
Not to mention if it's mud and gravel spraying right into the calipers, it both squeel and rubs.

I guess both R and RS 785 retracts just about same same?
Isn't it just the way the brake hose is attached which is the difference?
Anyway, i have the RS version.

Would be really nice if anyway had the Hope versions.
I contacted two dealers in EU, but none had any hands on experience with them.
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by Weenie


justaute
Posts: 227
Joined: Fri Jan 04, 2013 7:17 pm
Location: UT/TX/PA, USA

by justaute

FWIW...based on my exchange with Hope, via FB Messenger, I'm not sanguine about its customer service; thus, at this point, not high on its product. I want to give my business to a smaller company like Hope, but the company does not seem to want it.

I'm wondering about TRP's new brake system. I've received excellent customer service from TRP, at least here in the US.

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