Trek Domane SL5 Disc Bike Review

Trek Domane SL5 Disc Bike

Trek pitches the Domane at riders making the leap from alloy to carbon, and promise, ‘smooth riding, speed and versatility at great value.’ They even suggest it’s ideal for venturing off the beaten path, and with 32c tires – the widest here by a good 4 mm – we can see why.

First impression

The wide rubber wrapped around the Domane’s rims makes exceedingly light work of the main road near the start of our test route. A continual cycle of tarmac freezing then thawing over the year has created a crazy paving effect on the road, which the Trek veritably glides over. It all bodes well for the ride ahead…

On the road

The Domane provides a ridiculously comfortable ride throughout. Besides the voluminous tires which soak up initial bumps from ripped, cracked and outright dangerous tarmac, the front and rear IsoSpeed decouplers ensure that, if we hadn’t seen the tarmac with our own eyes, we’d have thought we were on a runway rather than a battered B-road.

A compact 50/34 chainset allied to an 11-34 cassette gives a sizeable spread of ratios, equipping the SL5 for all terrains, and moods. It’s fairly girthy nature does cause unnecessary struggle when attempting to crest shorter hills in the big chainring, but so what if you have to sit down and select the little ring once in a while?

If speed isn’t your main aim, this bike has got your back. The flat-mount disc brakes, while no doubt responsible for some of this bike’s weight gain over the 2018 model, add a sure-footed feeling to performance, especially in any panic-braking situations. The seat cap (rather than post) also helps keep your rear end divorced from the road, while the Bontrager saddle is perfectly in tune with the rest of the build.


The Domane excels in the cornering department, in a way which is slightly counter-intuitive. You’d (quite reasonably) assume that feel for the road surface, and grip of your tires thereon, is key to cornering confidence. Yet, the way in which the Trek’s IsoSpeed system partially removes feel for the road demands that you simply put your faith in the frameset beneath you. The combination of this isolating system and 32 mm-wide tires means you just have to point the bike at a turn, nudge the bans, tip in and pedal out.

And fear not, the slick tires offer plenty more grip than you’d think. Although the SL5’s head angle is an endurance-oriented 71.4°, there’s still enough agility to thrill, especially when carving downhill turns. On the flipside, stability is assured at any lean angle, and there’s no sign of twitchiness from the front end, nor rigidity. This makes the Domane an ideal steed for a day in the saddle.

Or, dare we say it, a springtime sportive in Belgium. As long as you familiarize yourself with the little ring, this clever machine will ably propel you through, up and down the undulating, and harshly surfaced terrain of northern Europe. And you’d still be able to feel your hands afterwards!

Trek Domane SL5 Disc Bike Frameset


The carbon Domane’s almost organic ­shaped sloping top tube contrasts with a chunky oversized downtube, designed to retain lateral stiffness and aid the development of power. The seatstays, viewed in profile, appear almost as an extension of the top tube, curving toward the rear thru-axle. Both wheels are secured by this method, a fitment chosen to reduce chances of flex, robbing efficiency from both the steering and drivetrain.

The frame and its material are the result of extensive Finite ElementAnalysis and Computational Fluid Dynamics research. The SL5 features Trek’s ‘endurance fit’, which aims to give a stable but still racy feel. To achieve this, the headtube is made slightly taller. Given the number of headset spacers on our test bike, you can easily reverse the effect should you opt fora more committed riding position.

Compliance of the frame is greatly enhanced by Trek’s IsoSpeed decoupler (developed in partnership with Trek’s former sponsored rider Fabian Cancellara) at the rear. In brief, it decouples the seatpost from the top tube, allowing the former to flex independently of the latter. A similar system at the front end decouples the steerer from the junction of the headtube and toptube. Simply put, it works. Very well.

One blot on the Domane’s copybook, though, is that, while the gearing and rear brake cables are routed internally through the downtube, the front disc brake cable is crudely zip-tied to the left-hand fork leg. To our mind, you’d expect a neater solution than that on a £2,350 road bike.


The Domane makes use of Shimano’s most enduring, and popular groupset-105. The mid-level component range is employed for the 50/34 chainset, the 11-34 cassette, front and rear derailleurs, shifters and even the chain. It’s a unified approach, and it’s good to see that Trek didn’t opt for a cheaper solution for the chain. Flat-mount Shimano 105 disc brakes are actuated by the Japanese firm’s hydraulic-equipped levers. The jury is still out on the aesthetics of the larger hoods this necessitates, but they do give you more options for hand placement.

Finishing kit

Given that Bontrager is a part of the Trek company family, it’s little surprise to see their components used to furnish the Domane. Up front, a set of alloy 400 mm handlebars is clamped by a 100 mm stem, while at the rear of the bike, the particularly cosseting Arvada Comp saddle sits atop Bontrager’s ‘ride tuned’ seatmast cap, designed to mitigate the most intrusive vibrations transferred by the road surface.


Bontrager’s 32c R1 Hard-Case Lite tires are of the maximum diameter recommended for this frame by Trek, leaving 2 mm either side between rubber and fork leg/chainstay. We didn’t experience any rub, so have to assume that the thru-axles were doing their job as intended. Grip is not immense, but comfort is fantastic. The Affinity rims are a sensible addition to the build: durable, reliable, yet not the quickest to accelerate. But them’s the breaks-if speed is the key for you, you’ll probably want to look higher up the Domane range. The £3,100 SL6, for example, wears Paradigm rims, while the £4,300 SL7 gets Bontrager Aeolus Pro 3s. Although now we’re talking very serious money..


Frame: 500 series OCLV carbon frame, Domane carbon forks

Groupset: Shimano 105

Brakes: Shimano 105 hydraulic discs

Chainset: Shimano 105, 50/34

Cassette: Shimano 105, 11-34

Bars: Bontrager Comp VR-C, alloy

Stem: Bontrager Elite, alloy

Saddle: Bontrager Arvada Comp

Seatpost: Bontrager Ride Tuned seatmast cap

Wheels: Bontrager Affinity Tubeless Ready

Tyres: Bontrager R1 Hard-Case Lite, 700×32


Size tested: 52Chainstays (C): 420 mm
Weight: 9.4 kgHead angle (HA): 71.4°
Top tube (TT): 530 mmSeat angle (SA): 74.4°
Seat tube (ST): 475 mmWheelbase (WB): 1003 mm
Stacks (S): 561 mmBB drop (BB): 80 mm
Reach (R): 371 mm 

Rating: 8.7/10

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