Hayes had somewhat of a renaissance thanks to its powerful four-pot Dominion enduro and downhill brake, taking it to the next level Hayes then modified and upgraded this platform to create its best MTB brake to date, the Dominion T4.
The aim when developing the Dominion T4 was to reduce weight without sacrificing performance. Despite looking relatively unchanged, the Dominion T4 has had an almost complete overhaul which is claimed to have saved 100g a set over the standard Dominion A4, bringing the weight to around 280g at each end.
When it comes to brakes though everything is secondary to how well they bring you to a stop, I have been running these on my Cotic SolarisMax longtermer for the last four months to find out how they perform.
Design and specification
Hayes has used all the tricks in the book when developing the Dominion T4 to shave a fair chunk of weight off the standard A4, whilst keeping the majority of the Dominion’s functionality.
In the pursuit of lightness, the lever has received the most attention. The brake is still based around the flip-flop lever (meaning it works on either side of the bar) and features a split clamp lever to make fitting easy. The lever has Hayes Stable Rate Linkage and sealed lever bearings for a consistent lever pull ratio and a smooth lever feel. The most obvious difference with the T4 is the removal of the toolless Reach Adjustment dial on the lever, which is now adjusted using a 2mm hex key. Behind the lever, there is also a 2mm hex key to adjust the contact point. The T4 lever blade is made from carbon by Hayes’ sister company Reynolds to save more weight. There is a composite reservoir cover and the insides of the Dominion T4 get treated to titanium hardware, hence the T4 naming.
Low-expansion Kevlar weave hoses (100cm front, 180cm rear hose length) connect the levers to the four-pot calipers and operate using DOT 5.1 Fluid.
At the other end of these hoses are the four-pot calipers, which have their fair share of features too. The 2-Stroke dual port bleed system allows you to bleed the caliper independently from the lever and the Crosshair Caliper Alignment screws are there to aid fitment, although I stuck with the classic loosen bolt, pull brakes, tighten bolts method.
The Dominion T4’s require a 1.95mm material thickness for better durability and heat dissipation. The rotors are available from 160mm to 220mm although they only come in six bolt fitment. If like me you need Centerlock, you will need to source third-party rotors, I opted for SwissStop Pro 203/180mm rotors.
Finally, although the T4 and A4 brakes look very similar, the T4 has been on a bit of a diet as Hayes says it meticulously removed any extra material from the original design. So where does all this weight saving get the Dominion T4s, my review samples come in at 250g (75cm hose) which brings them close to SRAM’s latest top-spec Level Ultimate Stealth 4-Piston and Shimano’s XTR four pots. They are potentially lighter than Hope’s Tech 4 E4 and will save a decent number of grams over TRP’s DH-R Evo, although both these brakes significantly undercut the Hayes in price point.
From the first pull of the Dominion T4’s they impressed me, the lever feel is staggeringly light and extremely smooth. Power is delivered linearly as well, so no matter how much power you need, it's the same even lever-pull force. The result is finger-twitching precision over braking forces from pad contact to full power.
I also found the light lever pull made a huge difference to arm pump and overall fatigue on long descents. This allowed me to ride at full effort from the top to the bottom compared to SRAM levers which have a heavier lever feel
Durability and reliability have been good as well. From fitting to writing this the lever feel has been utterly consistent, as well as staving off heat build-up, brake fade, or needing to be rebled either.
The bite point isn’t the cleanest and the overall power isn’t as grabby as say TRP’s DH R Evo or Shimano XT. The Dominion T4s still have loads of power though and the way they deliver it using pinpoint accurate modulation makes them very effective and efficient at managing speed. They are incredibly easy to balance on the edge of lock-up for optimum human ABS braking control, avoiding those panicky lock-up moments when you squeeze a little too hard causing your wheels to lose traction.
The Dominion T4’s have tooled adjustment, lever reach can be adjusted by 15mm (there’s no SFL (Small Finger Lever) option like the A4), however, the bite point adjustment doesn’t feel like it has much effect. Despite this, I still found it easy to find a comfortable lever setup. My only other setup gripe is that the Hayes calipers are quite large so not all brake mount adapters will work.
Hayes Dominion T4’s are some of the best brakes I have used, the sensitive, light action levers flattering braking ability allows you to apply ample amounts of power perfectly. Not only does the light pull of the lever help braking accuracy it can also contribute to reducing arm pump on long rough descents so you can keep riding hard.
The weight-saving modifications and premium hardware can trim a fair amount of weight off too, meaning they won’t be out of place on a trail bike. Titanium isn’t cheap and the cost per brake significantly jumps up in price compared to the standard Dominion A4.
Tech specs: Hayes Dominion T4 brake
- Price: $324.99 / £340.00
- Pad options: T106 semi-metallic or T100 sintered metallic
- Weight: 250g (front brake, hose cut to 75cm)