I looked at the Hope RX4+ 4-piston disc brake callipers nearly two years ago and it's time to revisit that discussion. The reason is simply something I often repeat in my reviews: I don't like to descend.
If I had to call out a particular product category, it tends to come up the most often when I am covering something from our best road bike wheels. Wheels, especially deep aero wheels, have an outsized effect on descending stability because of the constant redirection of wind as you come around a curve. Still, it's hardly limited to that placement. Every time I test a new bike or tyre, descending capabilities are something I pay attention to.
Early in the summer of 2022 this came to a particular head when I headed to Italy. I was there to test product but also to ride the 138km Maratona dles Dolomites course covering 4230 meters of climbing. If that's hard to picture, what it means is that for almost the entire distance you either climb or descend and both directions are steep.
After a day with that much descending, I decided it was time for an upgrade. I'm not heavy and as such I don't experience brake fade. Instead, what I notice is that long, steep, and repeated descents cause the brake rotors to warp from the heat. When that happens the pads rub and while Shimano and SRAM systems recover quick enough, it's annoying. When I got back home I went on an exhaustive search to see what you can do to upgrade the performance of your disc brake system and how well the options worked.
Although I ran through a number of options in that article some were more extreme than others. There's things like making sure everything is in good working order but there's also upgraded pads and rotors. All good advice I still stand by but buried at the bottom is a few paragraphs about upgrading your brake callipers and that's where I discuss the Hope RX4+ brake callipers.
As I write this, it's been close to two years since I started working on that article. True, we are a few months short but please forgive the exaggeration in the headline. Give or take five months, it's safe to say I've spent a considerable amount of time assessing the Hope Rx4+ system. With the benefit of time, this is why there's nothing I recommend more often than a brake system upgrade.
What is the Hope RX4+ disc brake system?
The heart of the system is a single piece CNC machined aluminium calliper. This is similar to other high end designs from Shimano and SRAM but Hope certainly has a more industrial visual stamp. While SRAM and Shimano stick to smooth high gloss finishes with organic shapes, Hope is pure business. The CNC cut lines are on full display, there's no organic shapes, and there are options for Black, Silver, Red, Blue, Purple and Orange anodization.
In fact, that anodization is worth taking a moment to discuss on its own. I have both red and purple Hope systems and in each case it's a perfect balance of colour without feeling tacky. In my case, the systems are on an Enve Melee and a Look 795 Blade RS and even in the face of beautiful bikes, it's always the brakes that get the first mention.
Beneath the aluminium and colour, you'll find a four piston design. Each side has two pistons with the leading piston being a bit larger than the trailing and the smaller being similar to what you'll find in a Shimano Dura Ace calliper. Pushing the pistons is your choice of DOT or mineral oil depending on the brake system you are adding these to. Since the two must never meet, a distinctive M (mineral oil) or D (DOT fluid) is impossible to miss no matter who works on your bike going forward.
In the box with your callipers, you'll also find two pairs of pads for each calliper. The RX4+ uses the Hope E4 pad and you'll start off with red or blue as a choice. The red is your go to as an all around pad when you expect to see some wet and muddy riding. The blue is the less aggressive organic option designed for road riding. You'll also find blank brake blocks for bleeding and all the necessary pieces to bleed and integrate with the rest of your groupset.
Along with the callipers and pads, you will also need a set of rotors. You can take your pick of 140, 160, or 180mm floating design depending on your setup and you'll find the same visual feel as the calliper. That includes both the CNC details and the same choice of colours for the centre section. The centre and the braking surface attach with a rivet that allows up to 1-degree expansion to resist heat warping and the lockrings use an internal spline and once again offer the matching colours.
Each calliper weighs in at 81 grams while the rotors are 129 grams for a 160mm. Pricing is slightly above Force and Ultegra though it's below Dura-Ace and SRAM Red.
What is the point of upgrading?
Every single time I switch bikes to test something with standard brakes, it's fine. I often notice the noise from surface deformation after a descent but I don't have brake fade or issues stopping. Then I get back on my own bike with the Hope RX4+. Right away it's noticeable just how incredible the system is. The first time I squeeze the levers a bit it's right there. Tons of power and room to modulate with only a single finger.
The truth is, I went searching for exactly why the Hope brakes feel so fantastic. I've been using them for a long time and whatever details I researched initially, I've long since forgotten. I thought maybe the calliper design made them stiffer, which is what Hope claims, but there are other monobloc callipers out there and you still don't get the performance.
I also thought the rotors might be making a difference. I do run 160mm both front and rear but that's no different than any of my other brake systems. Hope also calls special attention to the fact that the rotors are a floating design with room for expansion but other systems use a floating design also. No one else calls out how much movement there is though, so I'll call that a maybe.
Then I pulled out a Shimano pad and compared it to a Hope pad. The Hope pad absolutely dwarfs the Shimano pad and the 4-piston design means that even with the larger size, there's even clamping pressure. Whatever other small advantages there might be, the pad surface is simply much bigger.
In practice what that means is that in my experience, at least with a SRAM Red system, there's a ton of initial bite. As soon as you ease into the lever, you've got serious power on tap. That leaves plenty of room for modulation throughout the full range of the lever and it leaves me feeling safer on every descent. I never drag the brakes and I try not to brake through the corner. I let the brakes do the work as I enter, then back off, and brake again after the apex. It's a beautiful feeling.
The Hope brakes are also there for me when I misjudge things. I was reminded of this experience when I went out for a lunch ride while writing this. I chased somebody a little more than I should have on a descent I thought I knew. The turn in the middle was a bit tighter than I’d remembered or anticipated. For a moment it felt like I might have a hard time slowing enough and my stomach dropped a bit. Then I eased on the brakes and easily pulled down the speed without locking up the wheels or even needing to take it wide.
I'd be lying if I told you there wasn't also a bit of bling factor that's enjoyable. It's probably 10-1 how many people notice the brakes before the rest of the bike and given my job often involves taking pictures of my bikes, it looks pretty damn good in pictures too. The Hope RX4+ is all business first but of all the things people upgrade and customise on bikes, this is an easy visual upgrade. I'm always surprised it's not on every high-end custom bike out the door of every builder doing that kind of thing.
Any downsides?
I've been running these for just under two years and I've never once regretted it. I'd do it again in a heartbeat and I'm just about to get the system set up on a second bike. The only downsides I've found are that it's a bit harder to find the pads and rotors. The rotors are also more expensive plus there's no Ultegra/Force level if you want to save even more money. Luckily I don't have to replace rotors often.
I've also heard people complain about noise from the RX4+ system but that one I'm a bit confused by. For me they completely solve the annoying warped rotor noise after a descent and I've yet to meet any brake system that won't make noise after riding in the rain. I'm not one to be particular about maintenance but when the brakes are bugging me I'll pull the pads and rotors and drench everything in Muc-Off Disc Brake Cleaner. It solves it every time and I don't feel like the Hope system needs it more than anything else.
