Hello Vital MTB Visitor,
We’re conducting a survey and would appreciate your input. Your answers will help Vital and the MTB industry better understand what riders like you want. Survey results will be used to recognize top brands. Make your voice heard!
Five lucky people will be selected at random to win a Vital MTB t-shirt.
Thanks in advance,
The Vital MTB Crew
Yup, now they have a tool rather than the dual rotor
I just wish it was that easy to push them back
On the Hopes you blow on them and they move back
you have to push them in straight by applying the pressure in the middle of the piston. Bit off to the side you tilt the pistons which makes them go in a lot harder. If you do tilt them push on the other side to straighten them in the seals again, you'll feel once you hit the sweet spot, they slide very easily.
Mine have been pretty inconsistent to be honest. Most of the caliper pistons are just too tight. I've actually had to fiddle more than a bit with mine, but after some hours in the shed + some rides it seems like I at least get less bs now. I at least get less and less rubbing after each ride, so something must be settling in as I was hoping for.
On a sidenote I will never use silicone grease again, and wish Hope never recommends it because no matter how little is used it just keeps seeping back out and ends up on the backplate of the pads even after several sessions with cleaning with isopropyl alcohol.
I'll be ordering the caliper bore cap tool soon so I at some point will just do a tear down of the calipers and do a proper clean. I'll just order new seals as well for good measure.
I was thinking at some point if the grease is coming out from between the metal and the resin part of the piston or if it's just from between the piston and the bore. I at least look forward to hopefully having completely dry backplates at some time, because now I have to regularly check and clean them to avoid contamination.
There was a wet spot behind one of the pistons straight out of the box as well, so all in all I just feel better if I pulled the calipers apart and refreshed them even though it shouldn't be necessary this early.
I think very easily it’s something else, Hope, Magura even I just do it with my fingers
Sram of all kinds require force, and I’m aware the more centered the better or they go all wonky
I don’t understand how much more it can cost to make them slide nicely with better tolerances
Even Trp got that sorted nicely
I don’t like the idea of lubing caliper pistons even if recommend, the latest stainless ones move very easily.
I believe it’s just between the bore and the stainless piston
Every time I wash the bike some water comes from there
At first I though it was dot leaking, then noticed that once dry it was gone
That’s some weird issues with the inconsistency, is it just related to pistons not moving/retracting properly?
How are you finding the brakes paired with those trp rotors? Also noise wise?
There's simply more friction between bore and piston on some vs others which cause the out of sync issues which means I have to fiddle a lot more with these calipers than I have ever done before with anything else. It even says that this is just normal in the manuals Hope share freely.
It doesn't affect performance at all though, so it's just a matter of the fact I cannot push all pistons back and expect all to be in sync when I pull the lever again, because that's not happening on either caliper at all. I also have to align caliper with the bolts loose and just pulling the lever(firstly I need to have tinkered with the pistons to have them slightly pushed out and equal on all 4 to be in the position they should mostly be in given narrower rotor than the full 3.3mm), and then tighen them down. Then maybe a slight tweak more with pistons. Also some times fixing some slight untrue rotor so that won't rub either. I thought initially my rotors were straight, but mine were also bent like seems to be the industry standard these days unrelated to the brand in itself.
I'm not sure if the bore or the pistons are the issue. It would be great if it was possible to just throw in new pistons that had better consistency in the precision and I could have pistons that moved smoothly because that was what I expected from these straight out of the box.
As I mentioned to another comment last week or something my brakes and TRP rotors work very good. So performance is just spot on. I have no other noises than the standard Hope squeel that I know is common with these brakes just per default. It comes and goes, so sometimes it's on the rear, and next time it is on the front. It doesn't affect performance or anything, so it is what it is.
Most brakes will have their traits, and this is just what we need to deal with when it comes to Hope. Just look at racing cars and how they squeel, it's just a result of performance just the same way highend suspension components often may have more noise than less good suspension.
Could be the bores, the pistons or the seals.
Re: Piston sync. See if you can find a Hayes Stroker Ace Caliper Repair Kit, p# 98-23971. While the bore plug tools will likely be useless to you, the caliper alignment tool will likely help sort out the bulk of your sync issues. I milled one down to fit Shimano 4 pots and it nipped in the bud issues on one of my brakes and a pair of issues on a couple friends' brakes.
I have all the 3D printed tools Hope offer the files for, that I bought on Ebay. I got two bleedblocks btw, one for full width and one narrower version for 1.8/2.3mm rotors, so just imagine an extra bleedblock together with the rest of this first image.
In the second image is a piston seal service tool.
It doesn't matter how many times I have pushed pistons in and out and even with silicone grease on the sides it's still not wanting to sync. That tells me that it's simply too much metal to metal binding.
Another thing I noticed on the rear caliper is that I cannot actually centre the caliper perfectly with the rotor because the bolts are already in the max position. I can only push the caliper towards the hub, but to align it I need to push it out which I cannot do. I've seen pictures of V4 calipers on the rear of other peoples bikes where they also have all the leverage towards the centre of the hub. Given the design of these calipers with all the chunk towards the outside it almost seems like they forgot the centre of the rotor slot isn't in the centre of the caliper.
Some may say this is negligeble, and you can still make it work, and the point I'm making here is that this is a constant issue for the rear brake together with the piston out of sync issues on brand new parts. It shouldn't be like this.
I thought I was just going to install the brakes, cut some hoses and bleed them, and blam. Nope, that was not the case. It's just a bit odd when the levers have no issues and function smoothly and, and you look at the machining and all the rest which is very good. Then the brakes works like they should once I've made the brake pads sit where they should.
Anyhow, it's almost tempting to use a dremel on the inside of the bolt holes for the caliper and just slightly polish off some material. About the pistons I have thought that through use that they will polish the bore so the binding might reduce by itself over time. If that's not the case or just simply not enough, I'll have to consider other pistons and throw in some new seals at the same time.
PS: I'm not going to buy a tool set for something else with several tools I cannot use. I already have a caliper alignment tool that you see in the first image, so not sure what that hayes tool does.
Have you tried this hub, rotor and caliper combo on another frame? Have you tried a different wheel and/or rotor on this frame? A different brake?
What I'm asking is this a Hope V4 caliper issue, a frame issue (frame model or specific frame even maybe) or a combination issue.
I only have one bike and no other wheels or other brakes or other rotors. I only have this bike with the parts attached to it in its current configuration.
There was no issue alligning the Shimano M8120 caliper these brakes are replacing, so it is this caliper that is the issue, and not the frame.
I found the hopes and other big rotor(thick) calipers need the rotors perfectly in the centre or they will always unbalance themselves and often rub.
Did you try contact Hope about these issues you’re having? On a new brake set they should either ship you the pistons and seals or a whole caliper to address the issues.
I’m on the same boat, almost, being on i9 hubs the rotor sists very close to the frame, yet I’m still with the caliper almost all the way out, but i can make it sit nice and centered.
Fair enough on the purchasing decision. Nice bit about the Hayes unit is the tool centers in the disc slot and prevents one side from being able to 'over-actuate'. But I am with you that on new wares it shouldn't be like this.
Looking at your pic, I am not convinced it's a lube issue since both outboard pistons look to be aligned with each other, they're setting to the same position. While a bore issue may be at hand, it could be three other things: 1. Debris in the system restricting the transfer port between the sides. This would cause the inboard pistons to move more than the outboard ones. 2. Incorrect transfer port depth. This could cause a fluid restriction between the halves. Wouldn't seem likely but manufacturing is full of pratfalls. 3. Undersized piston bores. I wouldn't say this is likely since you seem to be the only person experiencing it. Lucky you!
Those last two seem unlikely, again since production errors usually show up on multiple units, but shouldn't be discounted. One offs do happen, and nothing frustrates everybody involved more. I would definitely look at contacting Hope and get their take.
I align it by pushing the pistons on opposite side out slightly(the pistons that are the most advanced in the image further up are the ones that need to start fully pushed in, so ignore how it looks on that image), and then with bolts loose I pump the lever till the pads contact the rotor and then tighten the bolts with lever still pressed in. It's fiddly and can some times take a few tries, but it will work. The downside is that I have to do this. The caliper still won't be aligned, but I can use the brakes with no rubbing on either side with pistons slightly more advanced on one side than the other.
I haven't contacted them and I really don't want to end up without brakes in the middle of a season. That's why I thought it would be best to run them in as I stated earlier, and see if lots of use simply will polish the bores so they will move more freely.
The other thing is even if I was sent new calipers there's no guarantees they will be better, so I've just decided to use patience for now. I do get less and less brake rub after each ride, so I at least believe my theory can come true. I'll still tear them down though, just to clean out what ever silicone grease there will be, because I'm done checking the backplates of the brakepads to wipe them clean.
If you looked at my picture you would see it says caliper alignment on one of them. This won't help aligning the rear caliper though, because if I had enough room in the slot that the caliper bolts go through I would just align the caliper by eye because it's easy. You don't need that tool to align the caliper.
The issue is the caliper cannot be aligned at all because the caliper bolts are pushed up all the way against the inside wall of the slot it goes through. I thought I made this clear. So, now I know I won't be needing that tool set you suggested because none of it will help in any of this.
About the rest you wrote, read some of my two last comments to the other two people so i won't have to repeat too much.
Brake adapter needs to be offset.
I'm using the correct adapter from Hope, and I've already pulled it towards the outside of the frame before tightening the bolts so the few nanometers you will shift the bolt holes for the caliper, will give the maximum of leeway for centering the caliper. That was done prior to capturing the image further up.
I don't see any other way of offsetting it.
After going back and fourth for the last month I decided to pull the trigger on some T4V4’s to replace the Radic Kaha’s that I’ve been running for the last year. I figured my purchase should trigger some event that causes hope to release the new gravity brake causing me to have buyers remorse over the purchase for not waiting, but giving anyone else the opportunity to grab some discounted T4V4’s or the new brake… your welcome 😂.
Some initial impressions:
Last time I worked on a set of hope brakes was at least 15 years ago, and they always seemed to be shelf queens imo. I know that has changed but I’m happy to see/feel it in person. Pad retraction is pretty damn good, having struggled with mt7 for longer than I should have and coming from Kaha’s that are intolerant of any runout in rotors I’m pretty happy that these have a decent amount while still having short throw. Coming to that, the dead stroke is much much better than I was expecting, not sure if it’s exaggerated or what but with the contact point adjuster wound in for the least free/dead stroke I am measuring 14mm until the lever firms up. That’s actually very close to where I have the free stroke set on my Kaha’s, also adjustable, to maintain reliability. I will say, they have a heavier lever pull than both the Kaha’s and the Dominions, by a fair amount to the latter.
I pulled my Trickstuff pads from my Kaha’s to have a better idea of how they stop, with everything else being equal, tbh I feel like there is no difference in power other than I builds slower, more modulation, but required more lever throw to get there.
I was able to get the calipers centered on the rotors and have nearly equal piston extension front and rear. The bleed process brought back memories but I used a miniature hose clamp to secure the hose to the barb at the caliper which made it a lot easier to pull a vacuum and dislodge any bubbles in the caliper before I pulled the diaphragm and performed a push bleed from the caliper. The front brake was pretty poorly bled from the factory, the rear was perfect (based on lever feel prior to cutting the hoses) can’t wait to put some laps on them and hoping, pun intended, they solve my weird reliability issue that comes and goes with the Kaha’s…
Im curious to know how you like them with the power pads, they’ve been my favourite pads on every other brake I’ve used.
The nerd in me would really love to match a Kahas lever to the v4 calipers to have an even better feel with even lighter pull 🤔 and that would also increase the power even further
Same here, but the levers have been the pain point for me, the seals have started to drag so much that the MC piston spring wont return the mc piston and lever all the way. Granted it only happens after the bike has sat for a few hours and you can pump them quickly to get the seal to soften up and start moving again but its a pain in the a$$. If I can get them to replace the seals under warranty and fix the issue, id be happy to try it out! Until then they will be collecting dust on the bench.
that issue of slow return mc piston is why i'm getting mc seals and pistons from hope as a warranty 😅
from val di sole pits, spotted on jackson's bike
That's a chonky caliper just like the Mavens. Saints are well regarded here in the mountains so I bet these will sell pretty well. They will probably use LV fluid since the XTR levers are being used. Those two openings on top should be easy to cover so mud doesn't get in.
That orange warning sticker is definitely worth 0.001s of drag during a 3 minute course.
Anyone have hose expansion/burst data?
Hayes hose seems like an outlier—-wondering if any anecdotal experiences regarding it and firmness vs standard bh90/goodridge 5mm braided, etc
Trickstuff on their website have pressure ratings for their Goodrige braided hose and for their Beta Kevlar hose
Quite significant difference
Then you’ve got Hope claiming nothing changes and I believe is bullshit
It might make a difference when you’re applying like 80-100% brake.
It won’t make any difference when you’re lightly applying the brake, like 0-10%. You have to expand the hose before the braid can apply any force to it. It’s not like it’s pretensioned around the inner hose.
I do believe it makes brake feel different, sharper more defined bite.
That’s why pros use stiffer hoses on trp, stock ones are soft, you can feel them and see them moving while just using the lever.
Post a reply to: Nerding out on Brakes shall we? Not another tech deraliment