Hope RX4 Caliper

Discuss light weight issues concerning road bikes & parts.
dvq
Posts: 68
Joined: Mon Sep 25, 2017 1:36 pm

by dvq

I'd get a set if I could actually find some in stock in the US.

Geordiepaul
Posts: 60
Joined: Fri Jun 30, 2017 7:15 am

by Geordiepaul

dvq wrote:
Wed Jan 03, 2018 4:40 pm
I'd get a set if I could actually find some in stock in the US.
I had to get my local shop to order them from Hope.

ooo
Posts: 510
Joined: Sat May 21, 2016 12:59 pm

by ooo

Hope RX4 weight info from bike24 (without photo on scale):

128g - Flatmount front (for Shimano)
116g - Flatmount rear (for Shimano)
123g - Postmount universal (for Shimano)

Hope RX4 weight info from r2-bike (with photo on scale):

153.2g - Flatmount front (for Shimano, with pads and bolts)
131.7g - Flatmount rear (for Shimano, with pads and bolts)
121.7g - Flatmount front (for Sram, with pads and bolts)
114.7g - Flatmount rear (for Sram, with pads and bolts)

122.8 - Postmount universal (caliper, with pads and bolts)
111.2 - Postmount universal (caliper, with pads)
83.2g - Postmount universal (caliper only)
'

MichaelB
Posts: 435
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

Looks neat there Geordiepaul - my frame is postmount, so that's the option I'd be going for (as well as I use a 140mm rear disc).

The other option that I considered was the Magura MT5/MT7, but their price is much higher.

I'll either stick with the Zee/Saint or try the RX4 when the time comes.

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Klaster1
Posts: 218
Joined: Mon Aug 15, 2016 10:25 am
Location: Krasnoyarsk, Russia

by Klaster1

Geordiepaul wrote:
Wed Jan 03, 2018 3:17 pm
They are sooooo much nicer, better quality and spares are easily bought.
Can you check if pads retaining pin and bleed nipples (if there's one) are aluminium or steel? I'm close to ordering a set of RX4 too.

fatcyclistchris
Posts: 2
Joined: Sat Jan 13, 2018 9:52 am

by fatcyclistchris

Geordiepaul wrote:I have an RX4 flat mount caliper as I got sick of Shimano calipers leaking (I've had 4 leak)
They are sooooo much nicer, better quality and spares are easily bought.

Image
Nice looking brakes. I'm thinking of getting some. How easy were they to fit? Easily done at home? Do you have to replace any barbs or olives?
Thanks

Sent from my VTR-L09 using Tapatalk


Geordiepaul
Posts: 60
Joined: Fri Jun 30, 2017 7:15 am

by Geordiepaul

No more difficult than a Shimano caliper.
They do need a new barb and olive so if your cable is long enough to trim a bit off then it's not so bad. Otherwise new cable.

fatcyclistchris
Posts: 2
Joined: Sat Jan 13, 2018 9:52 am

by fatcyclistchris

Geordiepaul wrote:No more difficult than a Shimano caliper.
They do need a new barb and olive so if your cable is long enough to trim a bit off then it's not so bad. Otherwise new cable.
Cheers. Will check to see if I can pull some cable through the frame. Internal routing can be a nightmare sometimes

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scale29
Posts: 37
Joined: Sat Jun 04, 2011 5:40 pm

by scale29

Klaster1 wrote:
Thu Jan 04, 2018 6:08 am
Geordiepaul wrote:
Wed Jan 03, 2018 3:17 pm
They are sooooo much nicer, better quality and spares are easily bought.
Can you check if pads retaining pin and bleed nipples (if there's one) are aluminium or steel? I'm close to ordering a set of RX4 too.
They are steel.

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Klaster1
Posts: 218
Joined: Mon Aug 15, 2016 10:25 am
Location: Krasnoyarsk, Russia

by Klaster1

Well, I've got a pair now: a front flat mount Shimano and a post mount Shimano. Something tells me I'll have a hard time routing the front hose through the Workswell WCB-R-093 fork, it will either have to bend tightly (any advice, hot water?) or route it outside.

MichaelB
Posts: 435
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

Bugger there Klaster1 - one of the advantages with a banjo connection.

Maybe get a bit of sacrificial tubing and see what works. Looks tight though. :unbelievable:

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Klaster1
Posts: 218
Joined: Mon Aug 15, 2016 10:25 am
Location: Krasnoyarsk, Russia

by Klaster1

I managed to get myself a set of aluminium backed pads, but there's a catch: nobody makes aluminium backed E4 pads. Even if somebody did produce those 10 years ago for BR-M755, I failed to find any mentions at all. As per @MichaelB's advice and this post on MTBR, I decided to order a set of 4 pairs of semi-metallic, D02S-compatible, aluminium backed pads from Ali for a whopping 6.5USD during sale.

Here's what I did in order to fit the pads:
1. Ground down the backplate from 39.5mm to roughly 37.1mm. Anything will do, I used a regular drill with a sanding disc lying on a small stool, disc hanging from the side. I attached a stock E4 pad to a new pad with a pair of zip ties, back to back, controlled the drill with one hand and used another hand (gloved) to grind the bigger pad to match E4 pad width. When most of material was removed, I cut the ties off, tried to fit the pad into caliper and removed a small amount of extra material. You might want to use a caliper instead.
2. Stock pad spring won't fit the new pad, so you have to remove braking surface at sides too. Hopes are ~34.4mm and D02S are ~35.8mm. At first I tried a small file, but got nowhere at all. A box cutting knife works great, though: just chip sides bit by bit with a knife tip, use the Hope spring as a guide.

The modded pads have slightly less braking material than E4: 12.8x34.3mm vs 15.2x34.3mm. Also, the pin hole has slightly larger diameter, so the D02S pad sits lower than E4. No idea how bad this will affect the braking. Hopefully, in 1.5 months when the winter's over I'll be able to report how RX4 with modded pads compare to BR-RS785 and F01A pads. Or maybe not, if I notice no difference :mrgreen:
Attachments
IMG_20180225_201037.jpg
Top-left: D02S-compatible pad, stock.
Center-left: E4 pad, stock.
Bottom-left, center-right: D02S-compatible pads, tuned.
IMG_20180225_201148.jpg
Tuned pads weight.
IMG_20180225_201237.jpg
Stock pads weight.
IMG_20180225_201337.jpg
Hope RX4 Shimano post mount with tuned pads installed.

MichaelB
Posts: 435
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

Hi Klaster1 - a lot of work just for alloy backed pads. Hope they work fine. Personally, I would have stuck with the normal pads, but well done for giving it a go and letting us know the details.

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Klaster1
Posts: 218
Joined: Mon Aug 15, 2016 10:25 am
Location: Krasnoyarsk, Russia

by Klaster1

MichaelB wrote:
Sun Feb 25, 2018 10:52 pm
Hi Klaster1 - a lot of work just for alloy backed pads.
Given a total price of 10USD and two hours of work I wouldn't hesitate to repeat the process again to drop another 23g. This is nothing compared to other people dedication you can observe on WW. To each their own, we'll see how the pads work out soon enough. Come to think of it, the pad height shouldn't be an issue, these were designed to work like that in DH applications after all.

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