Shimano SLX 4-Piston Brakes Offer a Familiar Feel and Similar Power at a Better Price [Review]

Shimano 4-piston SLX brakes

• Price: $187 each
• Buy from Jenson USA and REI

If the amount of mountain bike brake options on the market aren’t enough, the delineations between each brand’s brakes can still be overwhelming. In Shimano’s mountain bike brake line, the most common options are of course SLX, XT, and XTR. Shimano’s XT brakes have earned a reputation as a middle/high grade brake. The 4-piston options are powerful enough for trail and gravity riding, they’re reliable, and easy to bleed.

After spending considerable time riding Shimano XT brakes on several different review bikes over the past few years — it seems like the majority of bikes I’ve seen include XT brakes over SLX — I was curious how the Shimano SLX 4-piston brakes felt.

Shimano was kind enough to send over a set last fall. They didn’t have rotors on hand, so I used a Magura rotor and one from Galfer and put the SLX brakes on the easy-to-equip Privateer 161 which is a hefty enduro bike with a knack for speed. With external cable routing I had one less thing to worry about during installation and after snipping the hoses and plugging them into the master cylinders, the Shimano SLX brakes were ready for action.

Before we get into the performance of the brake, we’ll dive into what the Shimano SLX brakes are and how they’re different than XT and XTR.

Shimano SLX Brakes vs. Shimano XT/XTR Brakes

Like the XT and XTR brakes, the Shimano SLX brake power has been increased by a said 10% and piston retraction has been improved. Shimano SLX brakes (445g per brake) weigh about 70g more per set than XTR and 35g per set more than XT. All three use a 15mm and 17mm piston combination, with the larger piston leading the caliper, and there’s a banjo bolt to adjust the brake line direction.

Where does the added weight come from? Shimano told us “The weight difference comes almost entirely from the recommended rotor pairing.” Shimano’s published weight specs for complete brakes are based on “Average weight (g) (kit for front 800 mm, w/ 160 mm recommended disc brake rotor, w/ lock ring, w/o adapter, w/ 2 bolts, w/ resin pad).  The recommended rotor for Shimano XT brakes is RT-MT800 while the recommended rotor for SLX is SM-RT70.  The calipers are the same weight. The SLX levers are 2g heavier because they have a plug in the place of the free stroke screw.”

Many times, the difference between the top-shelf components like the XT and XTR and others like SLX is the weight and finish, and the finish is clearly different on Shimano SLX brakes. The XT is a fairly minor upgrade with a more lustrous feel to it, and for some, that may be worth it. The XTR has a polished aluminum appearance that clearly alludes to a higher price tag.

Like the XT and XTR, the SLX brakes are available in a 2- and 4-piston configuration and they all accept finned or non-finned brake pads. The brake set we received came with a set of finned metallic pads.

On the master cylinders and levers, the Shimano SLX brakes keep much of what makes the XTs and XTRs great: an ergonomical lever blade, a tool-less lever reach adjust, a clamshell handlebar mount, and Servo Wave. Servo Wave is a feature that ramps up the action in the lever in the beginning of the stroke to quickly engage the pads with the rotor, and saves more room at the lever for modulation and bite power on the rotor.

The Shimano SLX levers have a smooth rather than dimpled lever blade and don’t have an adjustable free stroke adjustment which would allow users to adjust the bite point on the brakes. But not everyone is sold on how functional this actually is.

On the trail

Installation was quick and easy, especially on an externally routed frame. The front and rear brake lines measure 1,000 and 1,700mm long. On a long enduro bike, there was adequate line available. I lost a little fluid on initial cutting and installation and decided to skip a bleed at the time to see how they performed. As mentioned I set them up with 200mm Galfer and Magura rotors without issue.

The tool-less reach adjust expedited setup time, and the levers felt as familiar as any other Shimano lever. Aside from the smooth lever blade, my hands can’t tell a difference between Shimano SLX and XT brakes. Some levers and masters out there feel and look ginormous, and I appreciate the shorter blade and smaller body of Shimano’s brakes.

The SLX brake action feels similar to the XT and XTR. The action is light and you can feel the pads engage about halfway through the stroke. There’s a distinct bite point and room left in the throw to apply more power. The amount of power is similar to the TRP Slate EVOs I’ve been running on another bike and the price point is similar too. I was surprised to see the SLX brakes weigh about 130g more per set than the TRPs since the TRP is a hefty brake.

So these aren’t the most powerful, chompy brakes on the market, like TRPs DHR EVOs or Shimano’s longstanding downhill Saint brakes. Fatigue can build in the hands and forearms on long descents and there are moments where I’d like just a little more clamping force, but in most cases, the SLX brakes have been enough, noting also that they’re mounted on a heavy long-travel bike that’s ridden faster than a shorter-travel bike and taken to trails where descending is the priority.

After a few months, I gave the brakes a quick lever bleed taking all of about 10 minutes and traded a few pockets of air for fresh mineral oil. This produced a noticeable improvement in power. Seamless bleeds are always another reminder why I like Shimano brakes.

Around the same time, I added some Miles Wide Rough Riders to the lever blades. These are little stickers with a gritty surface similar to grip tape, although it’s not actually sandpaper so they’re easier on your gloves. At $8, it’s a pretty clever little upgrade and you don’t feel like you’re missing anything between the nicer Shimano levers.

My wife ordered a brand new bike a few months ago and after a descent I asked her how it felt. She responded “good, but it sounds like there’s some noise coming from somewhere.” It’s probably your brake pads, I told her, since the bike came with Shimano XTs and finned pads. “I’ve got the same rattle,” I said. This hasn’t been a big deal for me. There are some hacks out there to quiet the pad rattle, but I’ll probably try a set of non-finned pads when I’m due for a new set.

Overall, the Shimano SLX brakes have proven a worthy and more affordable option than the XTs and XTRs. I was mainly curious to see if the more affordable option could still match the power of the higher-shelf brakes with the acceptable concessions of added weight and the loss of a few other features. The Shimano SLX 4-piston brakes have proved themselves as a contender, especially with XTs selling for $40-50 per set more than the SLX.

Pros and cons of the Shimano SLX (BR-M7120) 4-piston brake

Pros

• Same power as XT/XTR for a better price
• Concessions in features are worth the price
• Reliable

Cons

• Heavier than other mountain bike brakes at similar price point
• Competitive options at this price

Closing thoughts

If you’re decided on Shimano brakes but questioning whether you need the added flash or features on XT or XTR, the Shimano SLX 4-piston brakes are a great option. They are heavier in hand but lighter on the wallet and feel nearly the same as the higher priced options.

• Price: $187 each
• Buy from Jenson USA and REI