The Hayes Dominion T4 brakes put the already popular A4s on a diet with some carbon and titanium bling. The power and modulation on offer with a light lever feel makes these brakes a delight to use however the idea of saving a couple grams in the enduro and dh environment where high-power brakes are used is a little whimsical. The price hike from the standard A4s is eye-watering but if you want the very best with some understated bling (is this an oxymoron?) then these are the brakes for you.
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Hayes Dominion T4 brakes – Technical details
The already very popular Dominion A4 receives some major bling in the form of titanium and carbon fibre to make the lightweight T4 variant. As with the A4, the calipers are built around four 17mm pistons and use DOT 5.1 fluid. A couple of unusual but welcomed features include two bleed ports on the caliper to allow for independent bleeds to achieve the best performance possible and Hayes’ Crosshair alignment screws which help get the perfect rub-free set up. As an upgrade over the regular A4 caliper, the T4 introduces titanium hardware, including mounting bolts.
Moving onto the lever, the most obvious change to the T4 is the carbon fibre lever blade which was designed by Renoylds and manufactured in-house. In the name of further weight savings, the tool-free reach adjuster has been ditched and now requires an Allen key, the bite adjust remains tooled as before. Titanium clamp bolts and a composite reservoir cover round out the T4 upgrades. The lever remains a flip-flop design so there isn’t a left and right version and the lever pivots around sealed bearings for a durable and smooth action.
As with the A4, the lever action is designed to be light using an added glide ring on the piston, and the design is intended to have the shorter dead stroke possible with a crisp bite point. A kevlar-reinforced low expansion hose is used, again to reduce any flex in the system that could affect the lever feel.
These brakes have a claimed weight of 257g which includes a 90cm hose and mount hardware, as a reference this is around 34g lighter than a SRAM Code Stealth Ultimate.
Hayes Dominion T4 brakes – Installation
Fitting the Dominion T4 is a very similar process to any other brake with the addition of the Crosshair system on the caliper which makes for fine adjustments to stop pad rub.
When fitting the rear brake, I had to remove the hose from the lever because of internal routing, and I was unlucky to have a very stubborn olive stuck in the lever body. After a lot of faffing, the internal barb broke, releasing the hose, resulting in me having to completely disassemble the lever to tap the olive from the inside. This was annoying, but the reassembly and subsequent full lever bleed were simple. It’s worth noting I didn’t have this issue on the front brake, so I think I was just unlucky on this occasion.
When bleeding the brake after a simple hose cut down, I didn’t need to complete a full brake bleed but it’s worth noting the full bleed process has an extra step compared to a usual. The addition of an extra port in the caliper helps get the best bleed possible with another escape route for the air to get out – this adds minimal extra work and is worth it for the best lever feel.
The crosshair alignment on the calipers is a very neat feature that all brakes should have, the fine adjustment afforded by the grub screws is a breath of fresh air. Being able to dial in the exact positioning of the caliper and it does not move while tightening up the titanium bolts is delightful.
Adjusting the lever reach is a little fiddly, and most sensible-sized multi-tools don’t have a 2mm hex key, so mid-ride adjustment is less likely. That said, I’m in the camp of set and forget, so the lack of tool-free adjustment hasn’t caused me any issues. As far as I can tell, the reach adjustment has no discernible effect.
Hayes Dominion T4 brakes – Performance
The bedding-in process was a quick affair, a couple of hard stops on the flat before dropping into the first trail had the brakes biting nicely but it did take a trail or two before the full power of these brakes came to party.
The lever blade is a very comfortable shape which I instantly gelled with, the flat and wide blade gives plenty of surface for a finger while the curve at the end keeps the finger nestled in the same spot. The carbon lever doesn’t offer as much grip as the dimpled A4 alloy lever however with the curved end I never had any issues slipping off the lever.
With the brakes up to temperature and working as expected, it didn’t take long to see what the fuss was about. The lever feel throughout the entire stroke is notably smooth and the initial bite is found with a surprisingly light touch even if there is a little more free stroke than I’d like. This smooth action helps with modulation where making small adjustments to maintain grip is easily done.
The outright power of these brakes is impressive but not outstanding. They won’t stop the earth spinning but there is plenty of power for aggressive riding and most importantly, it is very manageable. There are few brakes where you pull the lever harder and the brake provides more power but these manage it, the modulation and feel you get through the brake makes the power easy to predict and use on the trail. For testing the T4s were paired with Hayes D-series 200mm discs front and rear – I’d like to try and 220mm front disc to see if outright power would be increased slightly.
On longer descents I’ve noticed the brakes do get hot, they smell hot when you’re at the bottom of a steep descent – a bit like SRAM’s brakes. This hasn’t caused any issues with performance, I’ve not experienced any brake fade however it might be a concern on longer descents particularly abroad in the mountains.
The brakes have a very understated look, I would go as far as to say they look outdated and cheap in today’s market of sleek SRAM offerings and refined Shimano / TRP shapes. Although the carbon levers are nice, the addition of titanium doesn’t make these brakes stand out anymore which I think, for the price, is a shame.
Hayes Dominion T4 brakes – Verdict
The Dominion T4 brake retails at £370 per end without discs or mounts. No doubt the carbon and titanium are fancy, but from a functional performance perspective, there is nothing to tell these apart from the standard Dominion A4, which are £200 an end.
Other options include the SRAM Code Ultimate Stealth which comes in at £320. These have plenty of power, modulation, and a nice lever feel but need a little more setup to get the best out of them, and they aren’t as light as the T4.
If you’re looking for bling and aren’t too worried about the weight, the Hope Tech E4s, retail at £195 per brake. These were praised for the lever feel and power on offer but the lever blade may not be for everyone and bleeding them is a pain.
The Hayes Dominion T4 brakes carry over all the great things from the standard A4 brakes. The power, modulation and light lever action make these brakes predictable and a joy to use. The addition of a carbon lever (without tool-free reach adjust) and some titanium hardware is a hard sell when it adds £170 per end to the price tag.
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