TMB Review: Hayes Dominion A4 Brakes

More than any other brake that Thunder Mountain sells, the Dominion A4 won me over to how a high-quality set of brakes can transform your ride. That might partly be down to the brakes they replaced: a five-year-old set of SRAM Guide RSCs, which I’ve put up with for so long despite their mushy, vague feel because the bike they came with, a 2020 Specialized S-Works Stumpjumper, was otherwise so very good. And yet, the A4s made this trail bike I already love so much even more unimpeachable.

The ergonomics are excellent, and the functionality is top-notch, with ambidextrous levers for easy installation and service. The reach-adjustment knob is front and center and easy to tweak, even while wearing gloves. A hex screw behind the lever adjusts the pad contact, although the factory stroke setting is so dialed and immediate that I never even thought to mess with it. Having said that, Hayes could improve these already great brakes by switching that Allen key pad-contact adjustment to a tool-free dial or knob, as the current location is a bit fiddly.

What really sets these brakes apart, however, is the lever feel, which is both extremely light action and also completely linear. From the very beginning of the stroke, the power activates and continues to do so consistently across the extent of the lever action. And not only that, but it takes very little force to get the full, powerful grab of these brakes. Put another way, the stopping power here is a function of how far you pull the lever, not how hard. That means less hand fatigue and easier braking, which made every ride that much more enjoyable. And even on the longest, most challenging descents, for instance, a nine-mile alpine drop outside of Salida, Colorado, called Canyon Creek, the power and feel was completely consistent, no choppiness or fade.

There are other little niceties here, too, including a pair of grub screws on each caliper for quick and precise pad adjustments and dual bleed ports for the most consistent service. However, I never needed these features since I didn’t have to make a single adjustment over an entire year of testing. I did find the metallic pads, which I installed for max power, to be a bit squawky when wet, but that disappeared once I switched to the Semi-metallic pads, which come included. The only other slight niggle is the brakes’ aesthetics: they are clean enough, but look a little retro compared to, say, the TRPs.

These are premium brakes, but still the second least expensive of the five here. And, without question, they provide the top performance for the cost.

	Hayes Dominion A4 Brakes Bottom Line: This is one of the best all-around brakes I have ever run, combining predictable power, an easy-to-maintain design, relatively low weight, and the best, most fatigue-reducing lever feel I’ve experienced. I would run this brake across the fleet. Shop Hayes Dominion A4 Brakes
Hayes Dominion A4 Brakes Bottom Line: This is one of the best all-around brakes I have ever run, combining predictable power, an easy-to-maintain design, relatively low weight, and the best, most fatigue-reducing lever feel I’ve experienced. I would run this brake across the fleet. Shop Hayes Dominion A4 Brakes

by Aaron Gulley Aaron has been writing about cycling, travel, and the outdoors and reviewing gear for the likes of Outside, Bicycling, Velonews, and others for over two decades.