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ShimanoXT BR-M8120 Disc Brake


Item # SHIU18H

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  • Black, Left/Front ($209.99)
  • Black, Right/Rear ($209.99)
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Item # SHIU18H

XT BR-M8120 Disc Brake

Here at Competitive we have a saying that brakes only slow you down, and while we throw around the saying in jest, the truth of the matter is that only the best brakes are capable of stopping you on a dime. Shimano brakes have received universal praise for doing just that for years, and the XT BR-M8120 Disc Brake doesn't fail to impress with its quick-stopping power. With the launch of the new Shimano 8100 series we see some improvements made to the 8120 brakes, but largely they stay the same. You'll see the same 4-piston design for intensely strong stopping power and its improved heat dissipation over the 2-piston model, plus the same lever shape and integrated master cylinder, but with the addition of an extra 10% stopping power over the 8000-series brakes, and reduced rotor noise. The narrow clamp makes for a tidier cockpit to play well with remote lockouts and dropper posts, plus its compatible with the new I-SPEC EV design to save you more space on the bars.

While lighter riders rolling in smoother XC conditions may benefit from the featherweight XT 8100 series brakes, riders who are heavier and more aggressive riders who transition between trail and enduro riding will covet the increased power and modulation of the 8120 when things get steep, technical, and rowdy. Shimano opted to refine the brake levers we saw previously with the 8000 series, with updated Servo-Wave technology to match up with the next generation of I-Spec EV Rapidfire Plus shifters, with two-way release, instant release, and multi-release that offers more control and confidence in your modulation. Unlike previous models, the new 8100-series brake lever is built for both the 8120 and 8100 calipers, allowing your cockpit to feel the same when you transition from your all-mountain rig to your XC rocket. This new clamp features a more inboard clamp position modeled after the 9100 series, creating an extra point of contact between the bar and lever for increased efficiency and control, while minimizing its impact on cockpit real estate.

The calipers continue to use Shimano's reworked pivot location that we saw in the 8000 brakes, which offers improved modulation when you brake. The superior modulation is due in part to the Servo Wave technology that adjusts the piston's travel relative to lever travel. As you squeeze the levers, the gap to the rotor quickly closes, then slows to permit predictable modulation. This allows the pads to sit further inbound relative to the rotors so they are less likely to drag. The 4 ceramic pistons push Radiator Pads with integrated fins that dissipate heat and reduce fade on long descents full of trail features. An adjustable banjo fitting allows for easy hose management and the routing of various frame designs.

The lever/hose/caliper assembly is sold as a front or rear unit and comes pre-bled and ready to install, made even easier with its hinged split clamps so you don't even have to remove the shifter or grips. Rotors and adapters are sold separately and the XT Ice Tech Rotors are highly recommended.

  • Shimano's popular trail brake ups braking power and modulation
  • 4-piston stopping power offers quicker braking than 8000 series
  • Predictable modulation allows for precise braking
  • The ceramic pistons reduce heat build-up
  • Finned pads further dissipate heat
  • Clamp designed based on XTR for better bracing, I-Spec EV compatibility
  • The pre-bled lever/caliper/hose assembly is ready to install

Tech Specs
Lever Adjustabilitytool-less reach adjust, free-throw
Mount Typepost
Fluidmineral oil
Recommended Useenduro, trail
Manufacturer Warranty2 years

Actual Weight

Black, Left/Front
Black, Right/Rear

Actual weights are measured in-house by the Competitive Cyclist team.

Have questions? Chat with a Gearhead

What do you think about this product?


>Rating: 5

Replacement Pads

I've put it through the wringer
True to size

What's up with Shimano these days? Because I love these brakes. But I would love them much more if I could find replacement pads for them. They are non-existent...

>Rating: 5

Love these brakes

I've put it through the wringer

XT works great...stops my bike just fine.

>Rating: 5

Use these to stop

I've put it through the wringer

I love these brakes...XT works just fine, no need to buy XTR.


Is this lever mount compatible with my XT shifter pod circa 2017?

Hey gde2549364, This will not synch perfectly with your shifter as is, but there is an adapter for just about anything. There are often some options from Problem Solvers that could work.

>Rating: 1

Defective on arrival

I ordered Yeti SB5 and received the bike today. The delivery was quick. I was so excited with new bike hoping to ride tomorrow. After completed assembly (pretty straight forward), I tested the dropper, the front wheel break, and the rear wheel break. When I hold down the rear break lever, the oil popped from the caliper and the rear break didn't work anymore. This is a brand new bike. And it was said that Competitive Cyclist went through the quality control. Really? What if it happened while I ride the bike. This is NOT acceptable. Do I have to send the bike back to Competitive Cyclist for the repair? This is going to ruin my vacation times. Please help me for this matter.

>Rating: 5

Get the power!

I've put it through the wringer

This is a perfect trail brake. Not the lightest out there, but you get a lot of stopping power for the $$$. I was running the 2 piston version of these for a bit before switching to the 4 pistons. It makes all the difference when you are screaming into a turn knowing that you can shed some speed effectively and reliably when needed. Obviously, if you are going to lean a little more XC then the 2 pistons would do the job no problem. For some of the steeper sections and faster bits you find on the trails reach for the 4 pistons. :)