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My main complaint with XT 8120 brakes is that the pistons self destructed, cracked after about 6 months.
They also lose power if you run the levers close to the bar.
The bite point adjustment was useless, which limited how close you could run the levers to the bars.
Power was ok but not great.
I've been much happier on all issues since switching to code rsc.
I’ve got a 8120 set on my dh bike with 220 2.0 rotors front and rear. No wandering, but the power I was hoping for just isn’t there, especially compared to Dominion A4’s. Any chance to try different pads to see if any make a noticeable difference? I’d rather throw money at pads than give up on these brakes.
Yes—better than gr4 with 10mm bearing
Sadly
Issues: Brake lever blades snap to easily, occasionally had problems with wandering bite point (but always fixed by doing a full bleed or switching to putoline oil).
Enjoyed: Super easy to work with and bleed, consistent, good power and lovely lever feel.
Recently I got the Dominion A4s on a new bike. Ran them for 2 months but the overall noise that they had was just too annoying for me. But for modulation they're certainly better. All out power I'm not sure, but that depends on where I ride and live I guess.
I have MT520 on my older bike and M8120 on the newer one. The latter got the wandering bite point eventually, but only after I replaced both levers because I damaged them in a crash. I think I got on top of it with a half-arsed gravity bleed, still using the OEM mineral oil, but if not I'll do a more thorough one. Having said that, "wandering" made it sound (to me at least) like you don't know what you're going to get with each lever pull, but the behaviour seems to be very predictable.
The same crash resulted in an upgrade to some aftermarket ~2 mm rotors and now they're incredibly snappy, which I like a lot. On OEM metallic pads they do fade a little (i.e. I need to pull increasingly harder – they continue to provide enough power) towards the end of a run at Thredbo, but I use the brakes way too much because mountain biking is scary. I haven't tried any of the good aftermarket pads yet, primarily because they're very expensive here for what would just be an experiment initially.
The M8200 levers look fugly as.
Edit to add after reading mannebask's response: I've bent XT lever blades and they are at least inexpensive and simple to replace. Whenever I look at Trickstuff or Hope brakes with lust in my heart I remember that I'd probably bankrupt myself replacing blades.
After the nuclear winter there will be a cockroach riding a bike with 8120 brakes on it. They are perhaps characterised by the fact that they’re not outstanding anywhere, but they’re good enough almost everywhere and will stay that way after the fluid has turned to tooth paste.
There are plenty of better stock brakes, but few as robust. Sure there have been occasional runs with bad pistons but the reason people remember that is it’s been so rare an exception to the reliability.
Yeah it's easy and not expensive for sure. Just annoying that they're a bit fragile. I rammed one lever of the Dominions straight into a tree first run in high speed, not even a scratch hehe. But a valid point for sure, I tend to keep a stock of old blades from buying broken levers and old take offs.
Issues: leaky pistons
Enjoyed: with 220 rotors and mtx gold pads, I thought they were a great brake for an enduro bike. Also enjoy the shimano brake feel.
I wouldn't buy another shimano brake without trying out some of the other brakes on the market first. Whether right or wrong, shimano brakes have become synonymous with "leaky pistons" in my mind, and I would need to shake that thought before buying another set or caliper. I like the levers tho, so probably back to a shigura setup before trying a set of evo pros.
In my mind shimano brakes are synonymous with “brakes that might suddenly decide to bite 5-10mm closer to the handlebar”
I have 8120’s on my Sentinel and they’re being replaced with GR4’s once I pick them up from the LBS tonight.
Issues: self adjusting bite point (eventually lead me to buying different brakes), pad rattles, easy to crack pistons
Likes: easy bleed, lever feel, every shop has parts
Shimano brakes have been bombproof for me. So easy to bleed and can even get them feeling fresh with a lever bleed. Also a big fan of the on/off feel while running Koolstop sintered pads and 203 Icetechs. In 6 years of running SLX brakes (which do about 150-200 rides a year), I've broken one lever and encountered a leaky calliper that needed replacing once. My ownership and riding experience have only been positive.
I've tried and liked RSCs, but I run Shimano drivetrains and like the integration without having to buy matchmakers. Put SLX/XT/RSCs on my bike and I'm happy.
What was the part number for the new brake pads that were compatible with the old 4-piston XTs? supposed to not rattle as much or something? Can't find a definitive answer
How did you make that work? All I am getting is too little lever and piston movement -> poor seal rollback -> locked wheels.
Work great here?
That being the case - does that mean the EVO blades would fit a Tech 4 lever? I want a more hooked blade.
No, evo blade on tech 4 doesn’t
Tech 4 blade on evo master yes
Main downside is the self-contaminating calipers. Spoke with Shimano and they had 'never heard of the issue,' which made me laugh out loud. I think all Shimano's ceramic piston brakes are prone to leaking. In the shop, I see their road calipers contaminate pads at 10x the rate of any other reputable brake manufacturer (sorry Promax, you don't make the cut). They don't leak during a pressure test, but leak during storage. If your current XT brakes aren't leaking, I don't see any reason to try the new ones, unless the new lever ergonomics are really much better.
Lever ergonomics is ok for 81xx series. I'm currently using them with Sram Motive brakes.
Fresh 612s in the works
Tried lots of Shimano brakes, all the same issues.
The wandering bite point is the biggest one for me. When temps drop below freezing, if you pull the lever twice in quick succession, it'll grab at a different point. My experience is every set of Shimano brakes I've ever gotten on does this, but the people who don't experience it use a different braking technique than those that do. If you are on/off quickly a lot, then you'll notice it, if you tend to make longer single pull drags or have longer gaps between braking, you won't notice it.
I've had some that leaked around the pistons. I never had cracked pistons but know folks who have.
The fluid turns black very quickly. According to the rep at Shimano I spoke with, this isn't normal, but I've again yet to bleed a set that this hadn't happened to. Whether this means degraded performance, I have no idea.
Shimano customer support is nonexistent. Their lack of available seal kits means you dispose of them instead of rebuilding them if there is a problem, which is wasteful.
Power is very mid compared to other, more modern options (Hope, Intend, Radic, Maven). There is worse, but there is a lot better also.
I've had sets where the brake lever began to flop up and down, there would be a noticeable vertical play in the lever to the point it was bouncing around under your finger while you were riding. I gather the bushing supporting the lever blades wears out and it develops this flop, but admittedly I've only had this issue on prior gen M8020 levers. You have to run them a while for this to develop and it seems inconsistent, some do it, some don't, but still it's annoying to have suspended brake levers and feels cheap.
The wandering bite point has always been resolved by using another mineral oil (like Putoline) in my case !
The disposable nature of Shimano brake components is a real head-scratcher and a bit of an anachronism in today's world. Is there anyone doing good quality rebuild kits that can be trusted?
As for the colour of the fluid, I once bled a set of lower end Shimanos only because they hadn't been done for three years and a few thousand kilometres – they still worked fine otherwise. The fluid came out black but after the bleed they didn't feel noticeably different. It's possible the performance of the entire system was degraded, but they still felt fine and the visual condition of the fluid didn't seem to have much of an effect on the outcome.
On rebuilds, Magura is the same way. I don't get it either, but it's not something I'm a fan of with them. For an industry so heavily invested in the environment, it seems silly to me brands like Shimano (and there are others) are so content to just tell people to throw stuff out if it fails and replace it. Maybe there is a technical or liability reason, but I'm not a fan of this when brands like SRAM, Hope, Hayes, etc all provide rebuild kits for levers and calipers. In the grand scheme of things we throw out, it's minor, I get it, but it just seems wrong to me when there are alternatives.
On the fluid, I'm not sure if the coloring matters or not. I probably wouldn't have made a comment about it except I had a Shimano rep directly tell me it wasn't normal. They told me to warranty them and throw them out. I didn't and they worked fine, so who knows what the right answer is. I've seen it go black after 1-2 rides and most sets I've seen had the same thing happen. I can't make sense of whatever it is and agree it's probably a non-issue, but Shimano says otherwise.
I've used the phenolic caliper piston kits from Exnavi (found on Amazon/ALi) without issues, and indeed they improved brake feel. Less retraction than the ceramic pistons, leading to a sharper bite point, and importantly, no wandering bite point. I did try the Ti MC pistons but those were bad. Undersized which allowed the piston to rock and lose seal, generally at times when you didn't want em to. Gave em a go after one unit swelled up and began locking in the MC bore (Ala Sram) and the other nipped a P cup. After all the issues I walked away from Shimano brakes. When they work they work really well, but when they crap the bed they leave a big ol stain. The new gen seems to have acquiesced to phenolics on all models, but the plastic MC pistons remain. That keeps em off my bike parts diet.
FWIW, regarding the oil colouring, Sram's R and RS brakes, where the parts are painted on the outside, have a gray oil when you do a bleed after a while, while RSC and above brakes (not sure how that relates to the new bronze and silve rmonikers) are anodized, which means the master bore is also anodized and thus doesn't wear as much as the raw one in the case of painted outsides. The gray colouring of the oil are aluminium wear particles.
@lucacometti did a Maven vs. Motive comparison for us! Maybe a bit of obvious results, but still interesting nonetheless. #theforumknowsfirst
Video says Maven Bronze have 4x18mm, while https://www.sram.com/en/sram/models/db-mvn-brz-a1 says it's 2x18 and 2x19.5.
Who's correct on this one?
Also Sram spare parts catalog says:
2 11.5018.058.001 DISC BRAKE CALIPER PISTON KIT - (INCLUDES 2-19.5MM, 2-18MM CALIPER PISTONS, SEALS, O-RINGS) - MAVEN ULT/SLV/BRZ (A1)
2 11.5018.058.002 DISC BRAKE CALIPER PISTON KIT - (INCLUDES 4-18MM CALIPER PISTONS, SEALS, O-RINGS) - MAVEN BASE (A1)\
(I know, SRAM naming is also confusing for me)
I believe the bronze was the same as ultimate and silver with 2x18 and 2x19.5 and the base is 4x18. But I think they stopped making the bronze and replaced it with the base.
On the topic of Shimano brakes- I have found a setup that I feel is worth sharing. Match a TRP DHR EVO caliper, a Shimano brake line and a Shimano lever of your choice. Clean fluid, more firm bite point, shorter lever throw, consistency through the life of the pads, and more power. I have done this twice now, one with XT and the other with Deore lever bodies and they feel the same.
The part about the calipers/pistons is correct. Maven bronze has the same caliper as silver/ult/expert and based is 2x18. This would be the first I'm hearing about maven bronze being discontinued, last I checked (2 days ago) you could still order up a set of bronze brakes, but maybe that's just existing stock. Fwiw, this move would make sense, the bronze/base cost is very close and the base lever action does feel pretty damn good (smooth/light).
Cross-post from RideMonkey: I finally got around to trying LikeWater with one of my Mavens that needed a bleed. The viscosity difference from Maxima mineral oil is massive. Very easy to degas and dislodge bubbles. I did a cup (Pinner) & syringe fluid replacement pulling down from the cup, pausing after 1 syringe full to empty the old oil out and refilling the cup. Piston advancement and retraction (piston massage) seemed smoother and easier. Actual lever feel is about the same, maybe a *hair* smoother. No obvious leaks or change in feel after a couple rides. I'll probably swap over to this for the rest of my quiver as my brakes feel like they need a bleed.
Post a reply to: Nerding out on Brakes shall we? Not another tech deraliment