Trek Domane ALR 4 Disc road bike – review

The alloy Domane Disc frame impresses from the outset, but the ALR 4 arguably sits in the shadow of the 105-equipped ALR 5

Last year, we got our hands on a Trek Domane SLR 6 Disc and put it through its paces. It proved itself a very capable race-endurance bike, with the new front and redesigned rear IsoSpeed decouplers providing next-level ride comfort and smoothness. This is the alloy version of that bike, designed to provide that distinctive Domane ride without the mega price tag.

The endurance geometry is back, as is the older version of the (non-adjustable) rear IsoSpeed decoupler to boost ride comfort. However, that’s where the similarities end – this is an aluminium frameset, complete with a more cost-effective Shimano Tiagra groupset alongside the Japanese firm’s BR-RS405 brake system. Think of it as a budget disc Domane, with premium alloy construction.

It doesn’t look like a budget machine, nor does it ride like one. Instead, what you get is a frame that takes strong cues from the carbon Domane, retaining the compliant yet stiff ride.

Of course, it’s unfair to compare the alloy ALR 4 directly against the carbon SLR 6 bike that retails for £4,000 – this one hits the market at £1,400 – so the question is: can Trek make the alloy Domane as desirable to this portion of the market as the SLR 6 is to the high-end? Let’s find out.

The ALR 4 Disc is the most affordable disc-equipped bike in the Trek Domane family at £1,400

The frame – premium alloy and endurance geometry

Immediately the geometry of the Domane ALR is familiar as it’s the same as the one found in its carbon sibling. It’s an endurance geometry, resulting in an accessible and natural position that allows the rider to sit on the hoods all day long, while also providing the option to get down low on the drops in a pseudo-race position.

  • Specification
  • Price: £1,400
  • Weight: 9.84kg (56cm)
  • Sizes: 44, 47, 50, 52, 54, 56, 58, 60, 62cm
  • Website: Trek Bikes

It repeats the same trick as the carbon version by placing you more ‘atop’ the bike as opposed to within it, effectively allowing the frameset to do the work beneath you. The tubing is Trek’s Alpha 200 series aluminium, welded remarkably neatly together using ‘Invisible Weld’ tech, helping to give the alloy Domane a decidedly premium look.

You’ll also find a toptube that flares towards the IsoSpeed decoupler junction, progressing onwards in a prominent sweep as the tube splits around the seatpost junction and extends down the seatstays. Those stays flare outwards to accommodate the disc brakes, with space left over for far more than the supplied 32c tyres, which Trek indicate pushes the Domane a little towards the gravel adventurers in us too.

The same generous capacity is found at the front end with a Domane-specific carbon fork that boasts IsoSpeed branding, owing to the sweeping design and offset dropouts, said to improve front-end comfort, rather than any decoupler technology. You’ll also find 12mm thru-axles at the front and rear.

Otherwise, the frame has external cable routing with the exception of the rear brake hose. We can’t see inside the frame to check out the routing guidance, but the design does have the obvious benefit of protecting the hose from stones and the like should you take it off the beaten track.

The Domane ALR’s aluminium frame delivers a premium ride and looks the part, too

Finally, a word on the IsoSpeed decoupler. Remember that this is the old-style version without the ability to adjust the amount of compliance you get. But, while there’s no adjustability as found on the top-level Domane SLR carbon frames, its core purpose is still to quite literally isolate the seatpost and saddle from the rest of the bike and reduce vibrations kicked up by the road.

In my experience, alloy bikes are seldom as compliant as their carbon counterparts, so it’s interesting to see how this tech influences ride behaviour in an alloy frameset.

You’ll also spot hidden mudguard mounts if you decide the Domane ALR is a strong contender for a year-round or winter bike – on paper, we certainly can’t see why not. Meanwhile, we weighed the entire bike at 9.84kg without pedals in the 56cm frame size (Trek claim 9.78kg), so while not lightweight by any stretch of the imagination, it should compensate for this somewhat with a solid and dependable ride.

The ride – sporty, smooth and supple, a great combination

So what of that ride? Among my own bikes, I have a 2011 Specialized Allez that’s literally been there and done it with me. From the Etape du Tour in 2013 to various 100 mile UK sportives as well as being a general commuter workhorse, I’ve experienced what alloy – pretty old alloy, in this case – is capable of.

In truth, I’ve never felt the need to upgrade it for another alloy bike (its advancing years aside), and it still functions as my winter and commuter bike even now when there isn’t a fresh steed that need testing sat in my hallway.

Perhaps that’s understandable, given alloy frames have been around for longer than carbon, and innovations and developments, while undoubtedly made, aren’t going to blow minds as much as they might have once. The same applies here in some respects, but this is the first time I’ve ridden an alloy bike and thought, ‘now, this is worth the upgrade’.

Right from the off, the Domane ALR impresses with how it’s able to roll smoothly and efficiently, and mete out a great portion of road buzz. That older IsoSpeed decoupler is still an effective innovation, and although the seatpost is alloy along with the frame, it’s remarkable that you can barely tell. There’s not the same level of comfort as the carbon Domane, but the IsoSpeed decoupler and plush tyres do a very good job.

The Domane ALR uses Trek’s original rear IsoSpeed decoupler

Through the front end, the bike has a far more standard construction. The handlebar responds to inputs with composure and verve without losing feel; point the bike where you want to go and it’ll draw a confident line towards the apex of your manoeuvre, and you’ll have the confidence to trust it thanks to the pulled-back positioning of the front dropouts that shorten the wheelbase.

That was an issue I had with the front decoupler on the latest carbon Domane, in that steering inputs felt a little vague, almost as if Trek’s engineers had overcompensated. But here there’s none of that thanks to its absence, livening up the feedback and putting an extra sense of control firmly back in the rider’s hands. Some riders may prefer the more isolating ride served up by the Domane SLR, but here you have a bike that’s genuinely involving to ride, and with ‘involvement’ being a key ingredient towards overall ride ‘reward’ for me, I’m a happy man.

That preference left aside for a moment, the Alpha 200 alloy chassis is also impressive when the hammer goes down, despite the near-10kg weight. You can’t escape that weight but seated efforts and out-of-the-saddle pushes are dealt with great competence – with a bottom bracket area that feels stiff and markedly assured. It’s a feeling which complements the Trek’s endurance geometry, which is nothing like the sit-up-and-beg designs you can find on some endurance machines. If you wanted, I’m left with no doubt that you could opt to take your alloy Domane to a race or fast sportive, fit it with racier wheels and rubber, and be able to stick it with your competitors.

The build – Shimano Tiagra and BR-RS405 discs

Our test ALR 4 machine comes equipped with a ten-speed Shimano Tiagra groupset along with Shimano’s flat-mount BR-RS405 brakeset. While a little heavier and bulkier on the frame than the BR-RS805 Ultegra-level system we’ve seen a lot of lately, actual performance from the partnership with the IceTech-equipped rotors is practically the same as the lighter version. Power is on a par, and modulation is impressive too – much closer than it is if you compare Tiagra and Ultegra-spec caliper systems.

As a result, if weight isn’t your primary concern (and with this bike it clearly isn’t), the performance value from this system is superb. However, this isn’t quite matched by the Tiagra drivetrain, in my opinion. This is exemplified nowhere more so than in the lever throw and actuation of shifts, which can feel a little off. We’ve had experience with 105-level disc levers before, and the positive feel of moving the Tiagra STI levers to shift up or down simply doesn’t feel as crisp and definitive as it does on 105 and above.

The bike is supplied with a Shimano Tiagra drivetrain

That said, I can’t criticise the ergonomics of the BR-RS405 shifters, which feel practically the same as any Ultegra-spec system I’ve ridden. Yes, you get a protruding hood that houses the hydraulic gubbins, but that’s there so the main ergonomics at the contact points are maintained. As long as you don’t mind the look of them, the bottom line is they’re a pleasure to rest your hands on.

The derailleurs are also efficient thanks to last year’s redesign of the front derailleur especially, although shifting remains not as crisp feeling as 105. The ten-speed 11-32t cassette offers up more than enough range for practically every rider, albeit with fairly big gaps that some riders may find a bit of a nuisance. This cassette is matched to a compact chainset, naturally, so there’s a really wide range of gears.

The hydraulic discs provide confident all-weather braking, making the Domane ALR 4 Disc a true year-round bike

Let’s be clear, Tiagra is by no means a poor groupset, and here it helps keep the price of the Domane down, but the rewarding frameset is definitely capable of handling better. In my opinion, opting for the 105 version for £200 more should compensate most of these shortfalls, while you won’t necessarily be breaking the bank: it’s an investment well worth making on shift performance alone.

Elsewhere, the finishing kit comes from Trek’s in-house brand, Bontrager. This includes quality, dependable tubeless-ready rims and hubs complete with sealed bearings, and Bonty’s R1 durable Hard-Case Lite 32c tyres. The front end is taken care of with a Race VR-C 31.8mm handlebar – incidentally a comfortable affair with easily accessible drops – while the alloy seatpost does a solid job without being spectacular or notable in any way.


If in the market for a competitively-priced, year-round endurance bike, the Trek Domane ALR 4 Disc would certainly be on my shortlist. It’s solid, dependable, reliable and gives a rewarding ride that’s genuinely comparable with its carbon big brother. Of course, it weighs more, but it performs that trick that all high-quality frames can – it masks it with stiffness and responsiveness worthy of a bike worth more.

Furthermore, it’s very comfortable for an alloy bike too. While bikes further up the range benefit from the latest IsoSpeed innovations from Trek, in addition to a carbon frame, the simpler version of that tech used in the ALR frameset still provides a desirable setup, and allows this bike to shine considering the comparatively low £1,400 price tag.

Given the overall performance and ride quality served up by the frame, I nevertheless feel the ALR 5 Disc model with a Shimano 105 groupset looks a sure-fire winner for a £200 premium, but if that’s out of reach for you then the ALR 4 Disc remains a quality machine at a competitive price point.


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