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Yeah the GR4's are tight for space ay. Phenomenal brakes though, I love them. Best of all the brakes by far.
Yeah I also own two other sets of v4s, so agree with the bed it period. But I have been hammering the GR4 for a good period now, longer than it has taken to get to the sweet spot in the past with the v4. And have worked the pistons a lot too. The pad clearance on these just seems tighter. They are better than the v4, just require more tinkering.
pretty impressive yeah, i still have the little devil on my shoulder telling me to find some radic masters to pair up with the GR4 calipers
That would be a fun test, I'd hate to miss out on the ease of adjustability of the hope master though.
I've chopped a set of rear pads already haha, but such precise power for steeps and the likes 🤌🤌
i mean on the gr4 i'm maxed out anyway, lever full close to the bar and bite point all out, it's short enough and far enough
FWIW HS2s are 2 mm. Centerlines are 1,8 mm.
Random thought
Has anyone ever tried to run the Hope calipers either just the stainless piston? Without the “plastic” insert?
I’m curious if it would affect the noise at all, give that Trickstuff, Radic, Intend and more use the same style but empty piston and are quiet
With the master cylinder moving the same amount of oil and the piston calipers now bigger, you get less pad rollback (i.e. they sit closer to the rotor in the default, non-activated state). That's the trade-off for that power increase over the E4/V4s. FWIW I have had two Evo sets running concurrently since 1 month before the launch, a set of TR4s and a set of GR4s, and I can't say I can quantify more of a pad rubbing issue or anything like that compared to the previous generation. Granted, they are still pretty new and I did do some basic piston massaging to help them along initially, but they haven't needed much after that beyond the occasional slight pad realignment (which I usually do without even taking the wheels off...just push the pistons back into the caliper a bit by wiggling a flat screwdriver in behind the opposing pad, and twisting a bit, then pump the lever again while paying attention to how the pistons behave when they extend back out again - the goal being to not see the rotor move to either side when engaging the brake).
I'd advise against it for one reason alone: Stainless conducts heat mighty well. Those inserts are to help insulate those pistons and keep the fluid from boiling.
I get it, although I believe this is a 0 issue in the bikes, again considering the best brakes in the market have no insert and just hollow stainless pistons
Fresh review alert: we've tested the new HEL Advocate brakes, here are our thoughts: https://www.vitalmtb.com/product/guide/hydraulic-disc-brakes/hel-performance/advocate-71426#product-reviews-721041.
TLDR: go read the review, don't be lazy! 😃
Sure thing, but those pistons were also designed to be run that way and likely have thicker walls. Which also begets the q of would those Hope pistons' sidewalls buckle under braking load?
This is written on the Trickstuff Maxima page about the subject:
HOLLOW STAINLESS STEEL PISTONS
"The light and hollow stainless steel pistons in the brake caliper make a considerable contribution to the heat management of the brakes. The hollow cylinder design reduces the contact surface between the brake pads and pistons to a minimum, while the stainless steel itself has low thermal conductivity, significantly reducing heat transfer into the brake caliper. In addition to stainless steel, air also has low thermal conductivity. The air cushion created in the hollow cylinder therefore also makes a positive contribution to heat management."
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Their pistons look pretty much identical in sidewall thickness and you somehow believe they will just buckle under load. The shape of the piston is identical to the cylinder it lives inside so any load will be spread out evenly and absorbed through the caliper. I'm sure you overestimate the forces in a bicycle brake, as well as the Hope pistons should be able to do exactly the same thing as the Trickstuff pistons so the only difference is the difference of opinion from one company to another.
Personally I'd actually like to try this out myself on my V4 calipers, it's just about 6 months till season start so no rush here.
Trickstuff Maxima Pistons and seals
When I'm doing a lot of braking with my V4s and things get hot, I find the rotor is what is holding the majority of the heat, not the fluid. Not sure what effect I would be looking for by taking the inserts from the piston.
*Using 2.3mm thick 220mm rotors, purple Galfer pads, not getting noise.
I like messing around with things/voiding warranties an awful lot, but I also like to do so with a reasonable degree of caution. Maybe it's a non-issue or maybe there's a silly reason or two those Brits slapped in a phenolic insert into their caliper pistons. That insert is a (relatively speaking) new addition to their calipers so something seems to have been learned for them to add another component to the mix.
Newer centerlines (A2 variants) are 2mm, they refer to them as rounded edges uci compliant etc. I'm not sure when the switchover happened but I've noticed them turning up more frequently on bikes.
You certain of that? I just bought a set of rounded edge centerlines for a bike I was selling (to take new hs2's off) and they were still 1.8mm.
The 160 rounded might not be, but I've seen 180 and 200 versions both in 2mm
images might not have come through big enough to read, both are 1.7 minimum thickness and the 200 has that sticker stating its 2mm thick.
There's nothing wrong wanting to use Hope's solution with the insert. All I'll add is I'm sure Trickstuff and others would easily just add inserts to their pistons if they saw the benefits outweighing the cons. The same can be said about brake pads where some still swear by sinter pads, and others by organic, and how to bleed a brake and the list goes on and on.
Just because someone has implemented a solution doesn't automatically mean it is a good one nor the best one. Personally I do not know what differences I would notice without the inserts at this point, but I'm actually interested at trying given I also have too much squealing from my brakes.
I made a new thread specific to shimano maven combo: Shimano Maven - S-tier braking (Shaven) - The Hub - Mountain Biking Forums / Message Boards - Vital MTB
Just switched from Shimano XTs (8120) to Formula Cura 4, mostly for the silver color matching 😆
However I feel like the brakes are not as powerful as the Shimanos. I've bled them 2 times, all according to the manual and also looked up a few other methods on youtube. Running HS2 200mm rotors front and back and stock metallic pads.
Anyone in here with any good tips regarding the Cura 4? Or are they just lackluster in power.
"Average Joe" advise: Coming from SRAM G2 brakes to Cura 4 was a great update for my Canyon spectral years ago. After reading reviews/advises from other riders, I did change rotors and pads for Galfer in 2025: Wave rotors and red pads. They defintely feel better (to me). Cant give you any comparison with Shimano XT, sorry.
Just to put a word in on direct comparison, I had a bike with Xt8120 and another with Cura4, both with MTX red pads. I found the cura 4 easily more power on tap. So to me something seems weird here. I never used formula pads, but the enduro mag test made it seem a pad upgrade had a major impact on power, that maybe is the case here? The bleed shouldn’t matter unless it feels spongy.
I would try doing a full reset bedding process using acetone on the rotor and a bit of sandpaper on both the rotor and pads. Maybe there’s a bit of leftover issues with your old brakes and the bedding process went wrong. If that doesn’t work then consider a different set of aftermarket pads.
Galfer wave rotors and purple pads completely transformed my Guides. Highly recommend!!
Thanks, I'm thinking in the same direction that it might be the stock pads that aren't up to standards.
Lever feel is pretty good, although they feel less on/off like Shimano, more in the line of old Sram in terms of feel.
I have a set of galfer pads on hand that I might try instead.
Lever feel sounds right. The end of the bite point has a bit of flex at the end and isn't as firm as a shimano or a Hayes. But it should have plenty of power on tap. I can't quite say what is stronger between Cura4 and the Hayes A4, its just how the lever delivers that power that is different.
FWIW, I added the FRS/RCS lever aftermarket, and liked the change in feel you can get. It allows a bite earlier or later in the lever throw, almost allowing you to be closer between a Shimano and Sram feel. But if you like to run your lever close to the bar don't get them as stock you can run them closer than with the lever upgrade.
Are you sure those are stock sinter pads („brass-y“ golden backplate)? I’m running them exclusively (mostly cura2 tho) with great results on nearly every rotor I’ve tried.
The old organic formula compound (black backing) is weak in comparison.
I’m pretty sure the Cura 4’s ship with the stock organic pads which are pretty mediocre. The Formula metallic pads are a nice bump up in power and last a very long time. Alternatively the pad offerings from Galfer/MTX/Sinter/Trickstuff would all be good options to improve the power of them, likely better power than the metallic pads but shorter life span. I’ve previous ran Cura 4’s with Trickstuff power pads and while the lifespan of the pads wasn’t great when riding bike park, the power is really really impressive.
Yeah sounds exactly like what I'm experiencing. I would say the A4:s are more powerful for sure with a much nice lever feel. I wish that those brakes worked for me but the set I had (came on a new bike) made so much noise all of the time. Changed the pads several times to exclude contamination and even warrantied the brakes. Still hade a terrible noise when braking unfortunately so I sold them in a tantrum.
Yeah it's the sinter ones.
Post a reply to: Nerding out on Brakes shall we? Not another tech deraliment