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In Spring, Magura sent out a review set of their latest heavy duty disc brake – the Gustav Pro. Named after Magura’s founder they are a nod to the Gustav M, an iconic stopper from the world of Downhill MTB racing in the 1990s. Today, these new brakes are primarily aimed at e-bikes and thanks to a joint effort with Bosch, are ABS ready. Touching on some basics, the Gustav Pros feature four 19mm pistons per caliper, a large 12mm master cylinder piston and a handful of other new features, while being intended for – but not excluded to – use with burly 2.5mm thick rotors. I thought the Gustav Pros would situate nicely for testing on my Transition Regulator, so that’s where they ended up. Read on for the full review…
Details
- ABS compatible
- Optimized for 2.5mm rotors
- New “easy link” hose connection
- Four pistons (19mm)
- Independent magnetic pads
- 348 grams (claimed) / 368 grams (our scale, front brake)
- $362 USD
Beginning with the brake levers, although they maintain the same master cylinder orientation as other Maguras, the Gustav Pros see a handful of new features. First up is the hose connection dubbed “Easy Link”. While the lever bodies themselves are reversible, you can connect and disconnect the brake line simply by spreading open a clip, and then pulling the hose out. When you reconnect, you’ll most likely need to do a lever bleed afterward, so while they aren’t completely plug and play, it is a slick system. More on the hose connection later but it’s also worth pointing out that lever bodies have just one bleed port, so it is necessary to rotate one of them 180º on your bar when you do need to bleed them.
The long lever blades offer up lots of leverage and have a sizable hook at the end, with a comfortable shape to them. The blades are on the fat side of things and while I mostly got along with them I would like to see an update that allows the tool free reach dial to bring them closer to the bar. Lastly, one subtle feature you may not notice on first glance is the breakaway relief machined into the back of the blade (pictured above). In the event of a crash, this could potentially sacrifice your lever blade to save your lever body assembly and/or handlebar and thus, money.
Magura’s “Shift Mix” integration is pretty sleek and low profile, but the downside is that it doesn’t offer much in the way of adjustment in terms inboard/outboard placement. I got along with it swimmingly and found it put my controls in just the right spot. If you’re someone who prefers your setup less middle of the road you may want to stick with your controls’ stock clamps.
Moving on to the calipers, it’s almost hard to overstate how big and burly these things are. Until you see them in person it’s a bit difficult to grasp. Magura continues to offer one-piece calipers, which are more costly to manufacture and in many ways superior to alternatives that consist of two halves bolted together. A well designed one-piece caliper is higher in its precision, has fewer potential points of failure and offers much greater stiffness, so kudos for that.
The bleed port is in a logical and easy to access location that’s out of harm’s way. I did appreciate the fact that the hose fitting doesn’t mount parallel to the rotor, rather it’s intentionally off axis. This makes angling the line away from the spokes and toward the frame an option both front and rear thus better achieving a nice, clean routing. Lastly, note the bridge spanning over the pad pocket which helps to increase stiffness.
The Gustav Pros use four independent brake pads, pictured above with the Black Sport pads. Allowing the pads to move separately allows for better heat dissipation and improves performance in muddy conditions, making for better expulsion of the elements. Like most Maguras, they use a magnets, as opposed to a physical spring to keep them up against their respective pistons. More on that later…
As mentioned prior, the Gustav Pros call for, but don’t require 2.5mm rotors. While thicker rotors helps to improve heat management, it’s worth noting that the rotors will also be tougher and stay truer with less fuss as well. You could opt for thinner rotors to save weight should you choose, or you can also err toward running smaller diameter 2.5mm rotors and improve clearance and thus reduce the instances of pinging your rotors on rocks. For example, my Regulator is 180mm Post Mount, so I opted for a 180mm rear, where if I was running a 2.3mm rotor I’d surely bump up to 200mm.
Setup
Getting the brakes bolted up and running was fairly simple in their initial phase, but not without some complications in the long run. Out of the box, both the lever body and caliper/hose come pre-bled. You’ll just need to puncture a membrane inside the lever upon connecting the hose. As a consumer, when you cut your hose(s) to length there are two options: You can use the included hardware which unfortunately requires small and uncommon 5mm and 7mm box end wrenches to cinch things up. The good news is that these stainless steel bits are nicely made and reusable, so if you want to trim your hose further after your initial setup, you can utilize the same fitting over again. The other option requires a specific tool to crimp permanent hardware onto the end of the hose. Whether or not your local bike shop will have that tool is another matter…
As far as setup went with the brake caliper, this is where things got a little finicky. For some background, I spent a couple of years riding MT7s on my personal bikes and am still of the opinion that it boasts the best power:weight ratio of any MTB brake on the market. When the Gustav Pro was announced I was hoping it would address my main complaint with the MT7: pad drag. Unfortunately that was not the case. Much like the MT7s, even if you carefully face your brake mounts and take great care to ensure a proper break-in with a nicely centered caliper and freely moving pistons all around, it’s nearly impossible to get the Gustav Pros not to rub under reasonably normal conditions. This is in large part due to the razor thin gap between the pad and the rotor, which is necessarily predetermined by the dimensions of the pistons’ square seals. In that sense there are no adjustments, workarounds or hacks to get your pads to sit further away from the rotor – that gape is unfortunately baked in. Some riders will naturally be more irritated by this than others. Broadly speaking, e-bike riders will likely be less apt to care as much, but I think Downhill riders and Enduro riders in particular would find it unacceptable.
On the trail
On my first couple rides out the Gustav Pros felt a bit vague compared to other high power brakes that I’m used to – and to be fair, I’d include Magura’s MT7s in that category. Although I found suitable power deeper in the lever stroke, the brakes didn’t offer up a firm, positive feel upon initial contact. I verified there was no air in the system with a bleed, then reached out to my contact at Magura, who told me to give them about 50 miles of break-in time. This period was to wear the pads evenly and to heat cycle the seals. This was helpful in honing in on the two factors contributing to the drag. First, the surfaces of the Black Sport pads were uneven enough that they didn’t sit nice and parallel to the rotor. Because the pads are massive and boast a ton of surface area they take a very long time to wear in correctly. The silver lining here is that the pad life is excellent, and while 50 miles is no big deal on an e-bike, it would be a deal breaker of a break in process for me on a fully human powered Enduro bike.
Secondly, I noticed that there was one stubborn piston on each brake that was reluctant to move freely even toward the 100 mile mark. This added to the drag and the mushy feel. I came to realize that it was the same piston on both calipers – located next to where the hose attaches. Magura assured me they have addressed and updated this with their most recent version of the brake. Looking at closeup pictures of the caliper at the beginning of the article you will see two small dots by the bottom / rearward mount. These dots indicate it is the second iteration of the caliper. The new calipers which have received the update have three dots and all four pistons move freely.
Another issue which has been addressed is the aforementioned pads. Part way through my testing Magura sent out a set of their Silver Performance level pads. Compared to the stock Black Sport pads, they had less drag, as they sat more parallel to the rotor right out of the gate and thus these pads hit harder and felt very positive. Magura is now spec’ing Gustav Pros with the Silver Performance pads as stock. I found that with the Silver pads the Gustav Pros offered up plenty of fade free power, even on very long, steep descents aboard an e-bike regardless of conditions. I also enjoyed their modulation and greatly improved initial bite. For perspective I found them have less of an on or off feel than a pair of similar duty SRAM Mavens, but with at least as much power, perhaps more. With the Silver pads installed I got along with the brakes quite well save for one last remaining quirk…
With both the Black and Silver pads, when riding with the brakes completely disengaged I noticed a disconcerting, audible rattle when going through high frequency chatter and small bumps. It took some time for me to diagnose, but I realized it was coming from the front brake and was caused by the pads rattling in the caliper. When I wiggled the pads I noticed a bit of free play up and down. The reason I couldn’t hear the rear brake rattling is likely due to the fact that the caliper is oriented horizontally, whereas the front brake is situated vertically. While this could be due to some tolerance which could stand to be improved, my personal opinion is that the magnets are probably not strong enough to prevent the pads – which are quite large and thus heavy – from moving. Perhaps a physical spring would do a better job of holding them in place but I don’t think Magura is about to change course on that front. To be fair, this didn’t affect the performance, but riders like myself who are attuned to bike noise will likely be annoyed by it.
Overall
All told I think the Gustav Pros – in their current production form with Silver pads and the V3 caliper – offer loads of power and a remarkable feel. These brakes do boast some great features and they are more than capable of slowing down inherently heavier e-bikes in the steepest terrain under the most demanding conditions. I’m reasonably confident they’re the strongest brake I’ve ridden to date, so it’s safe to say that power is far and away their greatest selling point. If strength is your number one concern, they’re worth a look. With that in mind, I found the finicky nature of their setup with regard to drag and pad rattle bothersome. Perhaps further updates to the size or strength of the magnets could address the latter, but the former seems unavoidably baked in. It’s worth noting that these aspects might not annoy every rider equally and that some of the noise is less noticeable over the sound of an e-bike motor or while wearing a full face helmet, which I was not. As far as value is concerned, at $362 per wheel I did not find that their power or feel makes them wildly outshine other options on the market which are sufficiently strong, more affordable and less fussy.
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[[{“value”:”In Spring, Magura sent out a review set of their latest heavy duty disc brake – the Gustav Pro. Named after Magura’s founder they are a nod to the Gustav M, an iconic stopper from the world of Downhill MTB racing in the 1990s. Today, these new brakes are primarily aimed at e-bikes and thanks to a joint effort with Bosch, are ABS ready. Touching on some basics, the Gustav Pros feature four 19mm pistons per caliper, a large 12mm master cylinder piston and a handful of other new features, while being intended for – but not excluded to –
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