If you don't have a disc brake-equipped singlespeed bike then you're obviously missing a niche: go out and buy one immediately. If you do, then obviously you'll know they're great. You don't have many options if you want a full hydraulic system on your disc-equipped singlespeed: there's this TRP Hylex system... erm, and that's about it. The good news is that it's an excellent system: easy to fit and service, with plenty of power and modulation available. And if you're looking to build a 1x Di2 bike then you can use Shimano's climbing shifter to make the Hylex Di2 compatible.
The Hylexes (Hylices?) have been out for a few years, but the RS is a new version. The most obvious difference is in the lever, which has a drilled-out blade which 'shaves weight as well as improves grip' according to TRP. It looks cool too; TRP forgot to mention that but it's pretty important. You can have the black finish that I've tested or a brown/silver colourway that will look the ticket on a more classic-looking singlespeed disc bike, if that's a thing.
Post-mount and flat-mount callipers are available; you'll need the FF-5 Front Flat Mount 140/160mm adapter to fit the front calliper to your fork. Since you're always going to need one, it's odd that it isn't supplied.
TRP uses mineral oil in the Hylex system. Shortening the hose (or cutting it to feed through an internal hose route) requires a new compression olive and hose insert. Pro tip: if you blast the end of the hose with a hairdryer to warm it up a bit you can push the insert in. The only issue I had was removing the cut end of the hose from the calliper, which required plenty of twisting and jiggling.
Once it's all back together, bleeding the system is easy enough. The TRP bleed kit (sold separately) contains everything you need, and it's really just a case of pushing oil through the system from the calliper up to the lever until all the air is expunged. I had to cut both lines to fit the brakes but only the rear one actually needed bleeding once it was back together. I had to poke a cable up the rear hose to guide it through the frame, and that displaced some oil; If you were just cutting the hoses to length for an external run you probably wouldn't need to bleed either brake if you were careful.
It's best to remove the pads if you're cutting the hoses to avoid contamination; the Hylex system is compatible with Shimano pads so replacements are easy to come by. The stock pads are TRP's semi-metallic pad compound which is good for all-purpose road riding.
I've got these brakes fitted to my Dward Design fixed gear. Because you need to adjust the wheel position with fixed, Ed designed the frame with sliding dropouts that move the rear flat mount with the rear axle. It works a treat, and the brakes do too.
With fixed you can adjust your speed with pressure on the pedals, but I like to have proper braking on hand on any bike I'm riding on the open road. And the Hylex system is excellent. The levers have a comfortable shape; they're not overly big because the master cylinder doesn't have to share the internals with any shifting gubbins.
The lever is easy to access from the hoods or drops, and the bite point feels more or less exactly right. You can adjust the reach of the lever with a 2mm Allen key through the front of the lever, and even when dialled right in the brake bites well before the lever gets to the bar.
Once the callipers do engage there's lots of usable power, and the brakes feel very easy to modulate. I've had a few squeaky moments in heavy rain (on well-used rotors) but for the most part the Hylex brakes have got on with the job without any fuss or bother, and the power on offer is at least one rung above the alternative mechanical systems. If you want good brakes on your disc singlespeed, these are, in my opinion, the best brakes that are currently available. They're neat, easy to fit, easy to service, powerful and easy to modulate.
The Hylex system has another trick up its sleeve. It's designed to work with a Shimano Di2 climbing shifter so you can have a single-ring Di2 setup with shifting on the lever. It's a some-assembly-required kind of a job, involving pulling the shifter apart and cutting a hole in the lever's rubber cover, but the end result is pretty tidy.
You'll need to factor in the cost of the shifter itself and TRP's £35 fitting kit. This used to be the only way of getting a single-ring Di2 drivetrain on your bike without having any redundant shifters, although now Shimano has unveiled its GRX groupsets there's an out-of-the-box Di2 solution, so it's maybe not as much of a USP. You could of course hack both your levers for a 2x system.
At £125 an end, the Hylex system isn't cheap exactly, but if you were to buy a pair of TRP's drilled mechanical levers and some Spyre callipers you'd only be saving yourself about £50 once you'd added some cables, and the performance of the Hylex discs is far superior. If you're building a bike that would suit them, or you're upgrading a bike you already have, they're a great buy. The other options are all part-mechanical: TRP's HyRd and Juin Tech's R1 convert to hydraulic at the calliper, and Giant's Conduct uses a stem-mounted master cylinder. All those systems can be used with STI levers as well as singlespeed levers; the Hylex RS is simpler because it's a dedicated singlespeed setup, and all the better for it if you're fitting it to your fixer.
Excellent hydraulic braking for your singlespeed (or 1x Di2 bike)
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road.cc test report
Make and model: TRP Hylex RS brakes
Size tested: Flat Mount
Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
TRP says, "A drilled out lever blade shaves weight as well as improves grip. This is a full hydraulic disc brake system for drop bars. It sports an integrated master cylinder in the low-profile ergonomically shaped lever body. This brake is for single speed aficionados, the rider who wants simplicity without sacrificing braking performance. Using our Hylex Di2 Adapter Kit this system can be used with a Di2 drivetrain."
Tell us some more about the technical aspects of the product?
Front Brake is a left-hand lever with 800mm hose
Rear Brake is a right-hand lever with 1800mm hose
Full Open Hydraulic System
Ergonomic and perfectly sized hoods create a natural extension from the rider's hands to the bike
Utilizes TRP's semi-metallic pad compound
Compound works well in dry conditions but may wear quicker in wet/muddy conditions
Post mount version compatible with Shimano M525/M515 pads
Flat mount version compatible with Shimano K02S/K04S pads
Rotors, adapters, and flat mount mounting bolts sold separately
All flat mount calipers being mounted to the fork require the FF-5 Front Flat Mount 140/160mm adapter
Pads are reasonably soft so won't last as long as full sintered pads but the braking is good.
Levers are a comfortable shape, reach is adjustable.
Not cheap, but it's not like there's another cheaper option out there.
Tell us what you particularly liked about the product
Easy to fit, work well, comfortable, adjustable.
Tell us what you particularly disliked about the product
No fork plate included.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
There aren't any, really.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your overall score
These are excellent brakes for your singlespeed. They're not masses more than a mechanical setup and better in basically every way.
About the tester
I usually ride: whatever I'm testing... My best bike is: Kinesis Tripster ATR, Merida Scultura
I've been riding for: Over 20 years I ride: Every day I would class myself as: Experienced
I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, club rides, sportives, general fitness riding, fixed/singlespeed, mountain biking, Mountain Bike Bog Snorkelling, track
Dave is a founding father of road.cc, having previously worked on Cycling Plus and What Mountain Bike magazines back in the day. He also writes about e-bikes for our sister publication ebiketips. He's won three mountain bike bog snorkelling World Championships, and races at the back of the third cats.