Trek Domane AL 4 Disc review

The original Trek Domane was possibly the most significant game-changing endurance bike, with its introduction of the unique surface-smoothing IsoSpeed tech.

The more affordable Domane AL frame extends the Domane ethos to a range of bikes that are mainly road-focused, but with enough substance to manage regular departures from the tarmac

If you're interested in bikepacking, look at the Trek Checkpoint, but if you think larger road bike tyres are the way ahead, the Domane AL has a lot to offer.

Trek Domane AL 4 Disc frame

Every Domane AL in the range uses an identical 100 Series Alpha Aluminium frame, which is hydroformed to create those carbon fibre Domane-like lines.

The top tube and down tube diameters flare in size before joining the head tube. While the down tube is generally oversized, the top tube displays Trek’s characteristic bowed profile.

The stays are straight, with a removable seatstay bridge supplied for mounting full mudguards, and higher, outboard mounts for a rear rack.

A third bottle cage can be fitted low down beneath the down tube, and there’s a top tube bag mount too.

The carbon fork has a tapered aluminium steerer tube, mudguard mounts and room for a 35mm tyre.

The gear cables and rear brake hose enter the frame high on the down tube and exit at the bottom bracket, continuing externally.

Trek says the Domane AL 4 Disc will take 32c tyres (as fitted) and full mudguards, or 35c tyres without.

Trek Domane AL 4 Disc geometry

The 56cm Domane AL 4 Disc, with its endurance-oriented geometry, is an almost perfect fit for me, at 5ft 10in (178cm).

The 175mm head tube means no spacers are needed (for me) between the stem and headset top cap. For general, everyday riding, it’s excellent.

The rear end shares the same 73.3-degree seat tube angle and length as the racy Trek Madone, while the 71.9-degree head angle sits between that of Trek’s Boone cyclocross bike and the Checkpoint gravel bike.

Combined with that head tube length, and a sensible 554mm effective top tube length, the Domane AL is roomy without feeling overly long.

Its 78mm bottom bracket drop is greater than the Madone and the Boone, improving ride stability without the need to leave room for extreme cornering (Madone) or rough off-road (Boone) ground clearance.

With its relaxed head angle and room for bigger tyres, the resultant 1,018mm wheelbase helps to maintain directional stability.

Trek Domane AL 4 Disc specifications

Positioned second in Trek’s Domane AL hierarchy, the AL 4 Disc currently comprises two options, at different prices, with two colours available for each.

The updated 2023 model, as tested, seems to differ only in its colour options versus 2022, and is £175 more expensive (in line with recent price rises).

Trek lists the specifications for both as having a complete Shimano Tiagra R4700 groupset, but the bike tested has an FSA Omega compact crankset.

My test bike came with an FSA MegaExo threaded bottom bracket, instead of the Prowheel one listed.

There’s an 11-32t cassette matched to the 50/34-tooth crankset, and Tiagra hydraulic disc brakes.

It rolls on Bontrager Paradigm wheels with Bontrager R1 Hard-Case Lite 32c tyres, and unsurprisingly, all of the finishing kit is from in-house Trek brand Bontrager.

There’s a Verse Comp saddle atop an alloy seatpost, a Comp VR-S alloy 42cm handlebar and 100mm-long Elite alloy stem.

The 56cm Domane AL 4 Disc weighs 10.57kg.

Trek Domane AL 4 Disc ride impressions

The Domane AL 4 Disc is aimed at regular riders who want a bike for training and leisure rides on the road, or even for taking in some light gravel riding.

With minimal tyre clearance and ambitions that don’t venture too far from tarmac, I tested the Domane in its natural environment.

Exchanging some fast roads for additional tortured lanes, dirt and more than a sprinkling of gravel, the Trek’s character was examined thoroughly.

Bontrager’s R1 Hard-Case Lite 32c tyres measured precisely as claimed on the Bontrager Paradigm wheelset, so I decided the best all-round tyre pressure compromise for my 75kg weight would be 60psi.

The tyres were supplied with inner tubes, but both the tyres and rims are tubeless-ready. Setting them up that way would permit lower pressures with very little risk of puncturing, and create more grip and comfort.

I ran the clincher set up with a little more pressure for security.

Trek's 56cm bikes fit me extremely well. The Domane needed no spacers below the 100mm stem, and with a few tweaks of hex keys and a torque wrench, I had my ideal position dialled in.

The Domane’s semi-compact frame has a very familiar profile, mimicking its carbon fibre siblings, even down to the distinctively shaped head tube. Only the welds hint at its metal construction.

It’s an attractive bike, well-proportioned and purposeful.

First impressions of the Domane AL 4 Disc on the road are of a very coherent bike, where the riding position and the build specification work harmoniously together.

The tyres conform well to surface imperfections, and really take the edge off large bumps. That feeling also gives great confidence in the twisty bits. The front tyre in particular finds all of the available grip, rather than skipping across it as a narrower tyre might.

Of course, tyre volume and pressure have a bearing on overall ride comfort and control, but they won’t mask a poor frameset.

Luckily, the Domane AL 4 Disc’s frameset is far from that, with an evolution of the IsoSpeed carbon fork up front, and the 100 Series Alpha aluminium frame, which is shared by every Domane AL.

The aluminium seatpost is 27.2mm in diameter, topped with Bontrager’s Verse Comp saddle.

The cockpit comprises Bontrager’s Comp VR-C alloy handlebar wrapped in a thin, grippy tape, and is attached to an alloy stem.

The groupset is mostly Shimano Tiagra R4700 (with the substitution of an FSA Omega compact crankset), and provides a familiar Shimano lever hood feel.

In my experience, slim alloy seatposts provide comfort-giving flex, but less so than a built-for-purpose carbon fibre equivalent.

However, the generously upholstered saddle supplied effectively makes up the difference, to the point where I had to double-check the Domane’s seatpost wasn’t carbon after all.

The Verse saddle has a rubbery feel to it though, which didn’t change with a little test wear, and is noticeable much of the time.

Seated comfort, even on fairly harsh gravel, is good, and holding the hoods ensures an acceptable level of comfort at the front too.

The tacky bar tape offers excellent grip, but it has minimal cushioning effect, which seems at odds with the Domane’s chosen specialist subject.

Holding the relatively slim tops or drops on rougher terrain requires gripping a little harder than I’d like. It’s something that could be fixed easily with slightly thicker tape.

It’s a very pleasant ride on the road, even on potholed and poor tarmac.

Whether threading a line between the damage, descending, or venturing off-piste, the Domane AL has reassuringly predictable handling that’s lively enough to be fun, but benign enough to keep you out of trouble.

Even when being shaken incessantly, the bike never felt overwhelmed, and navigated a composed route through the toughest road surfaces.

Tiagra’s 10-speed transmission worked faultlessly, the subbed-in 50/34-tooth crankset and 11-32t cassette giving a well-suited gearing range.

Shifting was smooth and slick, although the obvious downgrade is the FSA Omega crankset. It's reasonably attractive, weighs about the same, and fits in with the bike’s black components.

However, it doesn’t quite offer the same shifting slickness as a Tiagra crankset.

The Tiagra hydraulic disc brakes, though, felt almost as powerful as the 105 units seen on the Ribble CGR AL I've also tested recently.

It's hard to know exactly where the Trek wears the additional 1.16kg of mass it carries, when compared to the sub-10kg Ribble.

A little will be in the alloy seatpost, tapered alloy steerer tube and saddle, and the groupset may account for a chunk of the remainder, with some difference between the 28mm and 32mm tyres too.

However, on the road, none of that matters. The Domane AL 4 Disc is a very satisfying ride that doesn’t feel impeded by unnecessary mass.

It’s also a keen climber, with gears to conquer most of the terrain it could be expected to encounter.

On the flat, the Domane spins up to speed with ease, and sustains it comfortably, with enough in reserve to muster a reasonable sprint when the town sign comes in to view.

There’s not the urgency you’ll find from the best road bike wheelsets, but the Paradigms always give the impression of making positive progress.

Bontrager’s R1 tyres have a slick central band, and textured shoulders, which work effectively on and off the tarmac, offering that little extra grip on rougher surfaces.

Trek Domane AL 4 Disc bottom line

For road-based training and commuting, the Domane AL 4 is an impressive bike.

Plus, with wider and/or treaded tyres, and the use of the various accessory mounts, the Domane could make a fine all-road explorer.

As a package in the way its specced here, it’s very compelling, particularly if your ambitions don’t stray too far from the road.

Simple upgrades could also turn the Domane AL 4 Disc from a winter training bike into a summer trailblazer, and for many riders, that is adventurous enough.