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Bro I think you gotta stop dragging brake
Be warned, I’ve had a bunch of bad luck with Shimano rotors lately. I’ve had 3 or 4 that feel like they’re not properly flat and cause a pulsing feeling at the brake lever.
IMO the best value rotor at the moment is the HS2
Have really been liking the SwissStop Catalyst Rotors. They feel like they've got some texture out of box, gives them a bite that you can feel through the lever, and found bedding them in to be a breeze. Available up to 220mm. Alloy carrier and straight steel. Magnet holders for ebikes. Expensive, but not insane.
I don't know whether there was a running change at some point but every Shimano solid rotor I've tried in the last few years has been stamped but otherwise unfinished, so they very much aren't flat and do result in uneven and incomplete pad contact leading to poor performance. I'm using Hayes D-Series now and I'm very happy with them. SRAM HS2 would probably be a very good option too.
After all of the extra suggestions it seems like the SRAM HS2 is the best option so far. It does come in centerlock which is wanted so I can ditch the extra adapter. The pricing and availability is unmatched, so it seems to be the winner.
The only quirk I found is no 203mm option in this rotor, just 200mm. Then I'd need a new caliper adapter as well which is a bit annoying.
I had it with both the standard RT66 and a set of the fancier RT-MT800. RT66 was definitely worse but the MT800 was unacceptable too.
I went full XT on my new build. I’ve historically been a bit of a shimano hater and I felt like I should give it a fair go. The drivetrain is fine (i might even say it’s good value) but between the shitty rotor quality and the wandering bite point of my M8020 brakes, I’m pretty over their brakes. The lever suddenly biting closer to the bar is sketchy. At least my Mavens have the decency to bite farther away from the bar.
Hope GR4’s with HS2’s are going on both big bikes. Mavens and 8020 XTs are coming off.
Btw, I'm also wondering what pads are less prone to glazing if we look at metallic vs organic. I'm just trying to work out what setup will create the most ideal operating window. Stepping down in rotor size should introduce more heat, and maybe I should also pick a pad that deal better with heat(metallic)?
Just thinking out loud as I just need something that will work for once.
EDIT: Something that did cross my mind is that maybe the green Galfer pads would be best given I do not rack up that many miles in the short season I got so more wear I could deal with. I just see them for 21Euro inc. VAT right now and with a low shipping fee as well, so...
So maybe a powerful pad combined with a smaller rotor to get to a better operating temperature, and have the best punch for my personal riding. I also like that they should be ready to roll right out of the box, so no bed in needed. For the price they're at now I might as well just grab 4 pairs so I got backup given I don't really know how long they will last me yet.
At the same time it would also be reasonable to chuck out the phenolic inserts to get more heat introduced as well(I can always revert back if I need less...)
PS: Next time I buy brakes I'll get more trail oriented brakes, but for now it's experimentation time.
My previous bike was 27.5 150mm fox 34 fork with 203 CT’s. I thought I had a similar brake related issue where I was getting vibration through the entire bike at certain brake intensities. I’m the end I worked out it was the fork flexing back and forth rapidly. Certain speeds and braking power seemed to hit a prefect resonance of rapid back and forth fork flex.
RE: glazing issues. I also run the TRP S05E rotors also and occasionally drag brakes, depending on trail, depending on how steep. But that's cause it's steep, and they certainly are getting hot (I have a rotor shaped burn mark on my right arm from the last time I crashed - bike landed on me and rotor touched my arm for like 2sec before I could shove it off). They are my favorite rotor because of how true they come out of the box, and how quiet. For myself and others using them, the HS2 is decent and widely available, but always require a lot of truing out of the box. I forget if Galfer makes their Sharks in 180mm - but those are pretty good too. They're not as true as TRP though, offer the sharpest bite feel, and tend to be noisier. I also have noticed they produce a weird wear pattern on pads from the holes. Their Wave rotors are really noisy, and I had one come badly warped out of the box (so much I couldn't fix it). I'd run HS2 over Waves.
IME, Galfer green pads last 1/4 the time of sintered/metallic pads. I do think that you want organic/hybrid pads though if you think you're struggling to heat up the pads enough.
One final thought - if you want to try and correct your brake dragging habits, I'd suggest trying to make your brakes as powerful and sharp biting as possible. It will force you to brake in short bursts. Also at the same time try to practice braking early.
Your final tip is what helped me.
Pulsating through the lever is more likely a poorly bedded in pad rather than glazing. I'd recommend "resetting" your rotor by cleaning with IPA and giving it a good cross hatch scrub with 200 grit sandpaper, then clean with IPA again. Then do a pad bed in by slowing down 10+ times from a high speed, but never to a full stop. This will evenly coat the rotor with organic material and should stop the pulsing. If that doesn't work, I'd just drop the cash on a new rotor. It's worth the $50 to have those brakes dialed IMO.
Alternatively, if you really are dealing with glazing pads, just get metallic/sintered pads and glazing won't be an issue. They are made out of metal - you can't overheat/glaze those like you can organic pads.
I follow the bed-in procedure by the brand Sinter brakes, and I have a gps mounted on the handlebar so I can be consistent. I've done this every single time with these brakes, rotors and every time pads needed bedding in again. The pads look glazed, mostly in the front.
I get no discoloration on my rotors which should mean they are not getting hot enough, which is why I at least once would like to try a 180mm rotor in the front so I can have something to compare to. A smaller rotor working within optimal temps should give me more performance than a larger rotor running too cool if I've understood things correctly.
Alrighty. Thanks for that. So, what you're describing is a bad bed in. You have areas of high and low brake pad deposits on the brake track. You'll need to sand the rotor, emery cloth or an 800g or finer sandpaper works, to remove the inconsistent deposits, clean with isopropyl, and re-bed the brakes. I've seen and diagnosed this numbers of times, and even did it myself. Haste does make waste. Follow the manufacturer's guidelines for bedding the pads in and you should be good to go. Pulsing at the lever would indicate a defective rotor (uneven surface thickness), which isn't the case here per your description.
Whether you or anybody else get the same rotors hot enough is irrelevant to me, because I'm only talking about my own rotors which are only used by me.
Btw, my rotors were uneven straight out of the box and how even rotors are seem to be a bit of a lottery these days no matter the brand.
Yeah I think the Galfer greens will be what I'm opting for because I've found one shop(Bike24) who has those + the HS2 rotors in any size + adapters etc. and all at the lowest prices even on shipping and all. Some times it's very welcomed to be able to experiment without needing to pawn a kidney.
Regarding braking habits firstly I need to see how the new setup will behave, in order to know if it can be used or not.
First read my comment right above your comment because it will point certain things out.
+1 On the smaller rotors. I run the same SE05 rotors on T4V4's with Trickstuff Orange / Hope Greens and have not ever glazed them. Do you feel that they are getting glazed during the bedding in process? Or after they are bedded in?
What's your procedure for a reset? Sand and clean with ISO?
Do you typically see a little bit of discoloration on the rotors when bedding brakes in properly?
I'm asking because I have some discoloration on my rotors but I didn't check directly after I bedded in my brakes so I can't say when it happened. BUT I can say I noticed the discoloration before I took my bike on a brake-heavy ride. I'm surrounded by old XC trails so that's mostly what I ride.
The heart of what I'm asking: If there's no discoloration whatsoever on PB's rotors, then could we point to not enough heat being generated during the bedding-in process? Or does bedding in typically not produce any discoloration?
Testy, testy. That post wasn't there when I initially started typing mine, and your rotor warp wasn't mentioned previously. Good luck figuring your issues out.
As there's been quite a few suggestions now I kind of think I need to step back and just explain what it now seems to be.
From the get-go of these Hope brakes I had lots of issues with DOT fluid leaking and getting onto the pads. As certain people now have suggested I may have a poorly bedded in rotor, but I think it may be a combination. Maybe DOT fluid have been bedded into the rotor itself and I just haven't gotten all of it removed and that's what's causing the skipping.
Obviously cleaned with IPA more times than I can remember, but I still don't have a sanding machine. I tried utilizing an oscillating tool that I have and with sand paper attached, but it wasn't really the right tool for the job. I assumed it would at least help a little, but it probably wasn't good enough.
So, there's that. The rotor could possibly be saved with the right sanding machine, but none of this will answer the question in releation to operating temps for a rotor. As I've said both rotors are still very much silver color and no coloration through heat to be seen. Should the goal always be to get rotors close to brown-ish just to get a visual confirmation of well working brakes, or what?
Yes, but it also depends on what you mean by discoloration. If the rotor is blueing, that's def a heat issue. If you're talking about the brake track discoloring (taking on a different shade of grey) that's to be expected.
When bedding brakes in you don't want to generate a lot of heat in the system while doing so. Excess heating causes glazing, either to the pads, the rotor, or both. Semi metallic or organic pads can leave a bit of a darker stain on the brake track should that occur due to the organic matrix deposit getting smoked due to heat build up. When you get new pads and rotors on your car, the mech tells you to avoid freeways for 50mi or so. Reason is you need these low velocity, low load stops to properly deposit pad material. Making an analogy for bikes from that, you don't wanna hit DH lines on fresh pads/rotors for the same reason. Usually 20-30 good stops from a short sprint get my brakes working well. PB's symptoms (vibration with more grabbiness on some spots on the rotor) are consistent with what I saw in the field working races/events and testing prototypes. A couple of bad stops during a bed in will deposit more material in spots on the rotor. Bedding pads is easy, but like most things that are easy it also makes it easy to err.
You have contaminated pads - that is your issue. If you leak DOT fluid on organic pads, there is no coming back from that.
Throw that shit away. Get new brake pads. Thoroughly clean the rotors and start over.
I appreciate the info!
My bed-in process typically corresponds to with a late evening Trailforks ride up and down a road with a gentle hill by my house for 20 minutes. I take it easy and try to do it smoothly and gently-at-first to make sure I only have to do it once!
And, exactly like you said, an easy process can easily be done wrong. I was doing my typical gentle-hill-bed-in when a dog ran into the street. I had to stop and I even had the wherewithal to not lock the brakes up while stopping. But then, in walking the dog back to its home, I grabbed the brake and held it down for a few seconds. I noticed the ticking when I did my next bed-in run.
So I went home to do a light sanding, iso wipe down, and start another bed-in.
The old pads that did get contaminated was thrown away long time ago, so brand new pads was introduced after I cleaned out and sorted my calipers, so it's not the pads being contaminated really but I assume at least the front rotor being exactly that. The DOT fluid must've been bedded deeply into it and I expect that to cause the inconsistency issues, and it could probably have messed up my bedding in procedure so that it's just simply a combination of bs.
I simply feel like getting rid of that rotor + pads and try something else in the same go, but I just need some clarification in relation to rotor size.
is it cheap in the us? in the nz market those things are crap, let alone the lack os stiffness, 140nzd for a 200 rotor, a radic rotor is 2.3mm stiffer, better looking, lighter and 90nzd...
I had pretty good service out of the cheap Shimano RT66 but they wore too thin way too quickly. They only lasted one set of organic pads before they were under spec. Unexceptable.
Where are you guys finding the HS1's cheap? They are the same price as my go to rotor, the TRP ROS1E.
If my rotors get dot on them they get hit with a torch every single time. Burn all the contaminants off as well as as bedded in pad material. It could be that there is some pad material still on the rotor surface that’s contaminated. If you don’t have one a cheap butane torch is a huge help for cleaning contaminated brake rotors. I had lots of contamination issues with my radics and had to hit them with the torch regularly to get rid of the noise and restore bite and power. Sounds like you’ve tried a crap ton already but I would recommend the hot torch method if you haven’t already, or just toss a new rotor on there… Good luck!
Maybe a paint removal air gun would also work? They go up to 600 degrees Celsius and might be more useful for a home mechanic that doesn't have either...
I do own a 2000W heatgun that goes up to 630C/1166F. I do expect a torch to do more though which according to a quick search they do over twice of that.
I do see now that I need to get some extra stuff to deal with mishaps in relation to brakes. So orbital sander and butane torch should then cover some of the areas I've been lacking in up till now.
I'm still curious about the importance of getting coloration on the rotors vs no coloration though, because if my pads aren't glazed and all of this headache would be none existent without all of the contamination bs, then maybe the brakes would've been fine(?). This is why I now wonder if 203mm rotors will be fine with some organic pads like I've been running all along despite no coloration, or if 180mm would be necessary. 🤔
If nothing else, even at the same temperature, a flame will also burn off oily residue while an air gun might not.
Similar to this advice, my first instinct if I suspected a problem with the rotor surfaces would be to give them a quick lap with IPA. It won't help a warped rotor but it would otherwise knock down any egregious high spots while cleaning off any residues, and preps the surface for another attempt at bedding the pads.
Edit: of course this technique is not as straightforward if you don't use single piece rotors
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