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Hayes Dominion T4 brakes offer heavy-duty braking performance at a low weight

Hayes Dominion T4, title pic
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When I got into MTB, Hayes brakes were considered one of the top options and a lot of riders revered their carbon levered models. Over the next few years Hayes seemed to fall out of the limelight, until their first model of Dominion brakes came out in 2018. Today Hayes is announcing the new Dominion T4 brakes, an improved and weight-reduced evolution of the Dominion A4.

The T4 name indicates two things: The ‘T’ signifies that this model is adorned with titanium hardware, while the ‘4’ means the calipers have four pistons. Hayes set out to ensure the T4’s offered the performance and modulation their Dominion lineup is known to offer, but in a more refined, lighter package.

Hayes Dominion T4, caliper and lever

The T4 brakes weigh in at 257g per wheel, which makes the pair 100g lighter than a set of Dominion A4’s. Hayes didn’t change the core functions of the new Dominions, but machined away excess bulk and used lightweight materials wherever possible to reduce their weight. One such example is the hand-laid carbon fiber levers, made by Reynolds. Another example is the use of titanium hardware; The T4’s bolts, push rods, compression fittings and banjo fittings are all titanium. Furthermore, the T4’s reservoir covers are composite, and the brake pads feature aluminum backing plates.

Hayes says the T4’s are not the lightest brake available but they’re as light as Hayes could make them without sacrificing the level of performance they demand from their Dominion lineup.

Hayes Dominion T4, brake lever

The folks at Hayes know power is key, but modulation is even more important. The Dominion T4’s were designed to offer very light lever action, and the calipers employ a piston glide ring to aid smooth actuation. Individually calibrated master cylinder cutoffs provide instant engagement and brake fluid pressurization.

The ‘stable rate linkage’ shape of the levers helps the rider apply plenty of power with very little effort from your brake fingers. The levers rotate on sealed bearings, keeping friction to a minimum. The levers offer tooled reach adjustment, and their pad contact point can be adjusted as well. The T4’s ship factory-tuned for immediate engagement, but this can be altered to increase lever stroke before the pads squeeze the rotors.

Hayes’ levers use two-piece clamps and are flippable, which simplifies installation and potential replacement.

Hayes Dominion T4, caliper, backside

To keep power from degrading during heavy braking, the T4’s use Kevlar reinforced hoses which resist expansion and ensure powerful fluid delivery. Also, the KingPin brake pad retention bolt is a structural element, which reinforces the caliper for maximum grabbing power.

Hayes Dominion T4, action shot

In order to ensure consistent performance, the Dominion T4’s were built with 17mm aluminum pistons, which function smoothly within a broad temperature range. The brakes also run DOT 5.1 fluid, which has the highest wet boiling point of any bicycle brake fluid and remains viscosity-stable throughout operating temperatures. Mechanics will appreciate the T4 calipers’ double bleed port, which allows for caliper-only bleeding to help eliminate air bubbles.

Hayes Dominion T4, caliper, front
*Images c. Hayes

Last but not least Hayes has incorporated their nifty, unique Crosshair technology on the Dominion T4’s. On the sides of the caliper mounts, you’ll find little grub bolts which push against the mounting bolts to aid in aligning the calipers precisely.

The Dominion T4’s are backed by a lifetime leak-proof warranty. Pricing is listed at $324.99 per brake, with brake pads available for $38.99 per set.


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