Shimano XT brakes need no introduction. For many riders, loyalty to the brand’s mountain bike stoppers runs deep. While bikes may come and go, fans stick to XT brakes for the power, consistent performance, and quick bite. The latest 4-piston XT brake set, officially designated BR-M8120, boasts a few notable tweaks and improvements as I’ve discovered over the past several months of testing.
Shimano XT BR-M8120 Specs
Shimano XT 8100-series brakes are available in 2- and 4-piston versions (I tested the latter), and feature a painted aluminum body and ceramic pistons. My test set shipped with finned, metallic pads and all XT brakes utilize mineral oil in the hydraulic system.
Shimano says the current crop of XT brakes offers 10% more power than the last one, and they are quieter to boot. The brand also claims the latest design results in quicker piston retraction when it’s time to let go of the levers.
Rather than trying to weigh the brakes for myself (without the hose? with pads? do caliper bolts count?) I’ll go with Shimano’s estimate of 410g, on average.
The M8000 lever I tested is I-Spec II compatible and features both free stroke and tool-less reach adjust.
Shimano XT Brakes Installation
Installing the Shimano XT brakes went off without a hitch. The brake hose comes pre-bled and attached at the caliper, leaving only the connection at the lever to the buyer. A simple banjo-style connector makes attachment easy, and an extra barb and olive are included in the box in case the hose needs to be shortened. I didn’t find it necessary to bleed the brakes immediately after installation, though this may not be the case for every install.
Shimano recommends pairing the XT brakes with 800-series rotors, so I locked on a set 180mm Ice Tech Freezas. As a part of the XT component series, these brakes are designed with trail riding in mind. Out of the box the brakes are designed to fit 160mm rotors, though they are compatible with any diameter from 140mm to 203mm with the right adapter.
Aligning the calipers took very little effort: just spin the wheel, grab the brake lever, and wrench the bolts in place. After the initial set up, I haven’t had to make any alignment tweaks.
The lever mounts easily to the handlebar thanks to the open clamp band. Naturally these work well with a Shimano shifter for a nice and neat bar setup.
XT Brakes On the trail
Listen to any group of mountain bikers debating brake choices, and aside from talking about power, much of the discussion will revolve around modulation. Some riders prefer a more on/off feel, while others like to have a progressive range to feather along the trail. To be clear, it’s not that one is better than the other; like many things, modulation comes down to personal preference and riding style. Along the brake action spectrum, most riders tend to place Shimano brakes on the on/off side of center, and that seems to be a fair assessment.
That’s all a long wind up to say that these latest Shimano brakes appear to have shifted closer toward the center of the modulation spectrum. Compared to previous models of XT brakes, these feel more nuanced and yet as powerful as ever. Sure, you can still lock up the back wheel with a quick tug of the lever, or flip yourself over the bars with a short pull on the front brake, if that’s what you want. You can just as easily scrub the right amount of speed to land that double smoothly or to roll into that berm without wasting a second of time. For those used to the old XT brakes, these may require a slight adjustment period, though in the end, it should be worthwhile thanks to increased overall stopping power.
The M800 rotors are surprisingly lightweight in the hand, officially tipping my scale at 132.8g. Though Shimano claims the M8120 system “reduces disc brake rotor wobbling noise,” I can definitively say the design has not eliminated noise. After particularly wet creek crossings these can be downright loud, though to be fair, they’re no louder than any other brakes I’ve tested.
Shimano’s other claim, that the updated XT brakes offer quicker piston retraction, is a hard one to test. I suspect the updated and more progressive braking action is due in part to the ability for the caliper to glide more freely along its path, rather than sticking or stuttering along the way. Quicker retraction hints at a more fluid system with less resistance, which should also bode well for durability and lower maintenance over time.
The stock Shimano XT brake lever is a bit shorter than what I prefer, though that’s more of a personal preference. The tool-less reach adjust does make it easy to find the best position, and the free-stroke adjustment allows further customization for just the right feel.
Testing these brakes on long descents I found less noticeable fade than with others. Shimano’s design places a premium on heat dissipation, and the upshot is consistent braking from the top of the mountain to the bottom, and (hopefully) fewer bleeds over time.
Overall
The latest Shimano XT brakes should satisfy most trail riders, though diehard fans of the line might need a little coaxing to appreciate the updates. With dependable performance plus easy set-up and maintenance, XT brakes are still the ones to beat.
- MSRP: $209.99 per brake (rotors not included).
- Available at Competitive Cyclist and other online retailers.
Just wait til we get ABS!
That adjustable lever feature is very nice. Dial em in where ya like it and pedal!
So off topic, but what trail is that Jeff? It looks like a blast.
I haven’t used Shimano brakes so far because of all the reports about inconsistent bite point. Did that issue ever present itself on this set?
I’ve heard reports of an inconsistent bite point as well. My subjective impression is that the wider modulation range does make it tougher to keep track of where you are in the lever stroke, though I won’t go so far as to say the pads engage at a different point each time. Just that it is trickier to keep track of where you are in the stroke compared to previous versions which had a much tighter on/off range.
Mine are super inconsistent since day one. After multiple bleeds I figured out that one side of the pistons are not extending well enough to create power. Nothing I’ve found seems to solve this problem so maybe I just got a lemon set since the same brakes on my wife’s bike feels great. Used to not buy into all the inconsistent talk bc reviews were always pretty good, but now I know why some people are adamant that they wouldn’t trust shimano brakes.
The inconsistent bite points comes from the adjustment of the free stroke screw. Brand new XT and XTR brakes with this free-stroke adjustment with the screw is a non issue as it is new. For those having an inconsistent floating bite point to start with, get it warrantied immediately. It shouldn’t happen. After unscrewing the free stroke adjustment and then adjusting the free stroke again after bleeding, that little screw makes more indentations to the end of the piston rod. So, over time, that piston rod gets more loose or the seals get more worn from dirt getting into the piston. This happened to my XTR 9020 brake lever pistons. The worst thing was I was unable to take apart the brake lever piston without breaking off parts that were rivetted in for the piston ram rod. The newer XT versions are better that you can take the whole lever and piston assembly apart for overhaul. However, that free stroke screw is one of the worst design from Shimano. With the SLX 7100 series being the same in every which way as the XT 8100 with the exception of the free-stroke adjustment (lack of), the SLX 7100 levers should have no issues with the floating bite point over time. The reason how I discovered this was with my XTR 9020 leaking fluid after the 3 or 4th year. Then, I went onto Shimano’s technical forum for their retailers. Quite a few mechanics were definitely interested in the conversation I started. Then, one member said it may have to do with the free-stroke adjustment. As you look further from reports, none of the people who had the XTR 9000 race levers had that issue. Only ones with the XT and XTR 9020 brake levers with free stroke adjustments.
Shimano should redesign that free stroke adjustment so that there is no screw pushing on the end of the piston to make it move further in. The SRAM Code’s free-stroke adjustment is by far one of the best implementation by adjusting it at the ram rod to push the piston inward. This does not affect piston seals or pinching the piston at all. For all those who have the XT and XTR version of the brake levers with free-stroke adjustment, I suggest leaving that adjustment alone at all times. The adjustment can be minimal at best. However, if you don’t want the inconsistent bite point to occur, leave this adjustment screw untouched or get the SLX 7100 or the XTR race version of the brake levers.