The New Hayes Dominion T4 Brakes

[Press Release] – Never content to leave even the best design alone, the team of engineers at Hayes sought out to produce an even more extreme performance solution upon the solid and universally lauded Dominion platform. Improving upon such a respected system was to prove an arduous task, especially considering that no compromise was to be accepted on the quality or performance of the A4. The comprehensive analysis, design and development culminated firstly into the T2 model, and now the T4 (two piston and four piston respectively) which offer the trademark reliability, performance and modulation of the original Dominion platform, in an amazingly lightweight package.


The Dominion T4, just as its T2 sibling, presents the most gram conscious rider a zero-compromise solution at a significantly reduced weight. The Dominion T4 tips the scales at a scant 276gr per wheel, a whopping 100gr less than its A4 counterpart as a set. Such a reduction in weight comes thanks to a meticulous effort to eliminate excess material and customize componentry wherever possible. Leaving the core design and functionality untouched, the T4 incorporates sophisticated and lightweight materials where possible. The most significant reduction in weight is also perhaps the most visible modification, or rather the brake lever itself. Produced by Hayes’ sister company Reynolds, the hand laid carbon fiber levers maintain the same efficient ergonomics at a fraction of the weight. Such a light lever contributes to making the lightest lever action on the market even lighter.

The engineering team substituted bolts, push rods, compression fittings and banjo fittings for Titanium componentry (hence the T from the T4 moniker) and the reservoir covers were replaced with composite versions along with aluminum backed pads. The material choice for other components of the lever body or calipers could not be altered so in order to shave additional grams, excess material was found and eliminated through additional machining. While perhaps not the lightest brake system available on the market, these weight savings make for the lightest brake system that performs up to the lofty expectations associated with the DOMINION range.

Making a lighter brake is within the possibilities of nearly all brands, however the feather light T4 stands out for its performance and reliability, due to its Dominion DNA. The Dominion Project was carried out with no constraints in the form timelines, but rather only a lofty goal. Dominion was to be released only upon achieving a braking system that was capable of setting a new standard in addition to redefining performance. It was to stand apart from other solutions for its power, performance and reliability but also for ease of use, consistency and feel. Not only was it to excel in each of these categories but to do so harmoniously, accepting no compromise, as a fantastically functional complete unit that was to be as reliable as it was performance oriented. The first Dominion brake was launched by Hayes in 2018, that model, and each one to come after it, represents the same industry- leading complete performance package it did upon its introduction.

Such a successful braking solution was born from perhaps one of the most comprehensive and in-depth testing regimes ever employed for mountain bike brakes. The wealth of knowledge from such profound research and data acquisition met with the collective engineering know-how from the Hayes group who, in addition to an extremely specialized MTB development team, boasts teams dedicated to the development of solutions for motor sports, industrial and defense sectors. The elite project found that to develop a performance solution for braking would involve defining performance, a task a great deal more complicated than mere powerful braking. Simple raw power is important

but less so than fantastic modulation. The data shows that riders do a great deal more scrubbing than actual stopping which meant finding the perfect recipe between absolute power and control. While all the secrets to such performance can’t be revealed, several technologies incorporated to establish HAYES PERFORMANCE POWER bear mentioning. When an athlete needs brakes, he or she needs them immediately and the individually calibrated master cylinder reservoir cutoff provides for instant engagement via immediate fluid pressurization.

The STABLE RATE LINKAGE geometry of the brake lever contributes a great deal to the DOMINION performance as it confers great power that requires a very low force application to power applied ratio. To ensure that braking force never degrades despite even the strongest force applied to the lever Kevlar reinforced hose resists expansion and increases overall power and efficiency. The KingPin design is a structural pad retention bolt that reinforces the caliper, and thus increases power, while keeping the pads in place.

Dominion level performance derives from not only raw stopping power but through creating a system that inspires greater confidence and an overall better experience in the saddle. For example, whereas most solutions from other brands use bushings to facilitate the movement of the lever, the Hayes Dominion uses sealed bearings to require as little force as possible to actuate the brake, offering best-in-class, low friction tactile feedback to the user. The piston glide ring, a technology first used in suspension forks, contributes to even smoother actuation. This feature together with both lever geometry and sealed bearings make for an intuitive performance that has an unbelievable positive effect on ride experience. Power, modulation, feedback and lever feel all improve the rider experience and inspire confidence, but the brake must also conform to riders’ physical needs and wants to feel like a perfect extension of the athlete. By incorporating a patented tool-free reach adjustment the engineers at Hayes were able to deliver one single solution that can easily be adapted to every rider’s needs. Similarly, although the Dominion is tuned at the factory for immediate pad engagement, through the use of a tool the system can be adjusted to add the desired amount of dead stroke (how much action is required on the lever to engage pads toward the rotors) Having these two customizable options renders each set of Dominion brakes unique to each ride with a minimum amount of dialing in, and having your own personalized set of brakes increases confidence tremendously.

A-Series and T-Series Details


Hayes Dominion T4 – $324.99 USD

Brake pads – $38.99 USD

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