Review | Shimano SLX M7120 4 pot power for pennies

Andi bolted a pair of the Shimano SLX M7120 4 Pot brakes to a heavy eMTB and pointed it downhill to see if these mid-range stoppers are up to the job.

Shimano SLX has long been my go-to groupset over the years, and now that it comes in 12-speed flavour and with 4 piston brakes, this mid-range groupo is even more attractive.

The great thing about SLX is that it’s basically Shimano XT with a painted rather than anodized finish. There are a few material differences, and weights will vary by a few grams (with SLX sometimes being lighter) but overall the feel and function is comparable, well ok you might want an XT shifter, but keep the rest SLX and you’ll be laughing.

Recently while upgrading the brakes on my Patrol E-Six long-termer, the fine people at Shimano offered me a pair of SLX M7120 disc brakes to try. These new disc brakes benefit from trickledown XT technology including a new brake lever design, and 4 piston calliper, but only costing £154.99 a set they’re a bit of a bargain.

Shimano SLX M7120 4 Pot Features

Starting with the lever end of the M7120, Shimano has added many of the same features that you would find on XT to the SLX brake. The clamp is a split design so you needn’t remove everything to get them on and off and they are i-spec compatible for a neater installation.

Last year we saw XT and XTR levers get a bridge added to the design. The idea behind this being that the bridge or support prevents the brake lever from flexing when pulled hard in extreme situations. I’ve honestly never felt my old Shimano levers flex, but after riding the M7120 I do think they feel more solid, so perhaps there is something in that.

Also at the lever end, we have tool-free lever reach adjustment, but on SLX you won’t find Free Stroke adjustment. Not a problem for me as I’ve never played around with Free Stroke that much as I find the adjustment is only slight.

And just like XT, the SLX brake lever uses Shimano’s ServoWave Technology. The system is designed so that the brake pistons move faster during initial lever stroke, this means that very little movement is needed to get your pads at the bite point. Then as very little of the lever stroke has been used to initialise bite, the rest of the lever stroke is used for modulating power.

At the opposite end of the brake system, we get the SLX M7120 4 piston calliper. The new calliper design has a banjo type connection on the inside of the body to keep it away from damage, and the standard pads get air cooling fins for those long Alpine descents.

Inside the calliper, there are four pistons, two large and two smaller. The smaller pistons are located at the entrance of the calliper with the larger just behind. Shimano says that the design ensures that the pistons offer a large surface area for powerful braking and that the 4-piston design prevents movement and reduces noise.

I ran my SLX M7120 brakes with centre lock Ice Technolgy Freeza discs front and rear, though I believe SLX usually come with non-Freeza discs.

Shimano SLX M7120 4 Pot Performance

Shimano brakes have a very ‘Shimano’ feel to them. The Servo Wave system means that the brake can feel a little on and off depending on what you’re used to. I switch between SRAM and Shimano often and I get on well with both, and once you adapt to the fast-moving pistons in the Shimano brakes you soon learn to modulate power effectively.

I’ve been running the SLX through winter in mud, rain and snow, and they haven’t missed a beat.

In the past, Shimano brakes had been criticized for a variable bite point feel and I’ve experienced it a lot on older XT brake sets, but not on the new 4 piston SLX.

Sometimes this bite point issue just refused to go away, other times a thorough bleed is all that’s needed. With this in mind, I always give my new brakes a good bleed to ensure they’re ok when fitting, and so far so good.

As for noise, the only time I hear the SLX squeak or squeal is after a clean, a few metres of grit and dirt soon sorts that out. After that these powerful stoppers keep their cool while offering predictable disc grabbing mile after mile and silently too.

Shimano SLX M7120 4 Pot Overall

They’re basically Shimano XT 4 piston brakes that have been painted instead of anodized, so yeah, they’re damn fine stoppers. If you like the feel of Shimano you’ll love the added power of the M7120, if you don’t like the feel of Shimano then I feel for you.

Review Info