Trek Domane SLR 6 Disc road bike - review
Next generation endurance bike for riders who want to log big miles in supreme comfort
The Trek Domane SLR 6 Disc is festooned with technology that will provide a smooth ride on any surface you’ll want to ride it on – without losing its ability to get a move on.
Launched during the 2016 Classics season, the latest evolution of Trek’s endurance bike was meant to give Fabian Cancellara a winning farewell to the races which have made Spartacus a great in the world of cycling. With the exception of the Strade Bianche, it didn’t quite provide the fairytale ending, with Cancellara finishing second behind Peter Sagan at the Tour of Flanders.
But the Domane SLR is more than a Classics bike - it's leading the charge for the next generation of endurance bikes for everyday riders who want to ride big miles in supreme comfort. We’ve had our hands on a disc version of the Domane SLR to see if all the tech we discovered at the launch this spring really lives up to the hype.
The frame - comfort is king
Here we’ve got an SLR 6 Disc, built from Trek’s high-end 600 Series OCLV carbon fibre and all the innovative IsoSpeed technology Trek introduced earlier in the year, and teamed with the Domane’s swooping fork.
The Domane SLR Disc is based around Trek's relaxed Endurance geometry, to provide a more upright position and predictable handling, as opposed to the aggressive position and razor-sharp handling of a race bike. Still, you can get the Pro Endurance geometry used by the team if you go through Trek's Project One custom program - but that more aggressive fit is only an option on the rim brake frame.
Back to the Domane SLR Disc, and added into the frame is built-in support for Bontrager Duotrap speed and cadence sensors within the left hand chainstay, as well as internal cable routing throughout. The only exception comes in the front fork, which tightly binds the front brake cable to the inside of the fork, externally. While not creating the neatest and cleanest of front ends, it does make servicing that little bit easier - ideal if you plan to use your Domane over muddy cobbles, for example.
- Price: £4,000
- Weight: 8.3kg (56cm)
- Sizes: 48, 50, 52, 54, 56, 58, 60cm
- Website: Trek
Let's just recap on some the headline features of the Domane SLR frame. The Domane was first launched in 2012 with the innovative IsoSpeed decoupler, which isolates the seattube from the toptube via a pivot and allows it to flex independently to improve comfort - now Trek have upped the ante on the Domane SLR by making that level of compliance adjustable via a slider on the seattube. It can be adjusted by slackening one of the bottle cage bolts and moving the slider, before tightening the bolt back up again.
Secondly, Trek developed a front IsoSpeed for the Domane SLR which places a second decoupler within the headtube, with the aim of softening the front end, and providing a more balanced ride at the front and rear.
With all that the Domane SLR represents something of a tour de force in the endurance bike market, so we took it out on UK roads to see just how effective that innovation really is.
The ride - quick, compliant and relaxed
Fundamentally, the Domane SLR’s behaviour is dictated by the geometry and IsoSpeed. In this Endurance geometry, with slighter higher stack and shorter reach than the Endurance Pro, it’s a bike which feels like it sits beneath you with complete composure, while the slightly more ‘sat-up’ position is naturally easier on your back and arms (and inevitably less aero).
Of course, an endurance geometry is all well and good, but that in itself doesn’t necessarily lead to a comfortable ride - the frame itself can be just as raw and harsh as any super-stiff race chassis. Enter into the fray, IsoSpeed.
While Trek have introduced front IsoSpeed to the Domane SLR, the adjustable, rear IsoSpeed decoupler remains the centrepoint of the frame - and it’s a wonder for riders wanting maximum dampening through the saddle.
I’ve personally tried many variations of this kind of comfort-enhancing tech, from Pinarello’s K8-S suspension, Specialized's Zertz inserts (but not the new version of the Roubaix with front suspension), Canyon’s trick VCLS seatpost and varying carbon layups (see Lapierre’s revamped Sensium for one example) that purport similar claims of increased compliance without sacrificing speed, and this has to be the most effective overall setup I’ve experienced.
Perhaps the best thing about it is how adjustable it is. Throw the Domane SLR into maximum compliance mode, and it's better than anything out there for sheer vibration dampening. Stick it into minimal flex setting (still fairly vibration-nulling) and it’s 99% as responsive as, for example, the incredibly impressive Sensium that left me shocked with how racy an endurance bike could feel.
Why just 99%? The Domane SLR doesn’t quite take my breath away as the Sensium did, but it does get right to the heart of vibration-dampening in a way that Lapierre, Pinarello and Canyon's endurance bikes just can’t match. It’s exceptionally smooth.
That’s helped by the newly-installed IsoSpeed setup at the front end. It’s brilliant at working with the IsoSpeed handlebar (a strip of rubber runs inside the carbon here) to wash out buzz at the front end. The introduction of the front IsoSpeed came as a response to feedback from consumers who said the previous Domane felt a little too harsh at the front, exaggerated by the smooth rear. Now Trek have attempted to balance the front and rear, and it’s truly effective in providing an all-out smooth ride.
However, that does have the effect of isolating you from the road a little, rather than feeding back the nuances that come with every pedal stroke. That’s not to say you’re uninvolved in the experience, but it does have the effect of slightly isolating you from the bike beneath you, allowing the frame to take the punishment the road surface is giving without directing that harshness to you. For some, the ride may feel a little vague but it is undoubtedly a plush ride. Trek’s IsoSpeed technology has absolutely moved the game on for carbon endurance frames in terms of smooth riding, and this is where it shines the best.
Coupled with the geometry, which relaxes the handling by extending the wheelbase, and the Domane SLR is an incredibly easy bike to ride - it’s supremely smooth, well-mannered and remains planted to the road over tricky surfaces. There are concessions to be made with a geometry like this, and it loses an element of the responsiveness and agility that adds excitement to the ride, but on the flip side it's a very easy-going companion to spend the day with, and that's the goal for most endurance bikes. As we've already mentioned, Trek do sell the Domane SLR in a Pro Endurance geometry with a more aggressive fit and sharper, more agile handling, but that comes at a premium and is only available with the rim brake frame.
That’s not to say the Domane SLR won’t perform when the heat is turned up, however - the frame, ultimately, is one designed with performance in mind. Our test loop takes in a number of local climbs and, giving it the full treatment, the power is sent through the beefed bottom bracket with excellent efficiency. In this area, it remains a very stiff bike, and whether attacking a steep ascent or spinning up a shallower climb, it’s happy to take the punishment. The SLR gathers its speed in a more relaxed, linear - and less spiky - manner than a razor-sharp bike, but the BB90 bottom bracket oversized tube profiles ensure it’s not going to leave you wanting more when putting the power down. If fast but smooth and controlled riding is what you want, then the Domane SLR delivers that in spades.
The build - full Ultegra, discs and wide tyres
As we’ve already mentioned, the Domane SLR is available with rim and disc brakes, with six builds from £3,600 to £7,600 - the Domane SLR 6 Disc here comes in at £4,000. The Domane range also includes the SL, which gains the new front IsoSpeed decoupler but retains the existing, non-adjustable rear IsoSpeed, with options from £2,500 to £3,500. There’s also the Domane S, which ‘only’ has the non-adjustable rear IsoSpeed of old, and is priced between £1,400 and £2,000. Let’s not forget the updated, aluminium Domane ALR, either, which will set you back between £1,300 and £1,100.
The SLR 6 Disc is built with a full mechanical Ultegra groupset (compact chainset with 11-28t cassette, making for a wide spread of gears ideal for an endurance bike), teamed with Shimano’s flat mount RS805 hydraulic disc brakes. It’s a recipe for reliable and impressive performance on all fronts. We probably don’t need to describe the performance of Ultegra, except to say it’s excellent as ever, but the discs certainly deserve more of your attention.
The undoubted performance benefit of discs in poor conditions is clearly apparent when riding - from the great effectiveness when the rotors are wet or greasy, to the incredibly tactile modulation once the discs are under load. Whether or not the UCI re-starts its disc brake trial, discs remain an ideal option for an endurance bike and riders less concerned by the rules set by the sport’s governing body, and more the real world performance on slick roads and steep descents.
That being said, discs won’t appeal to everyone. There remains the issue of the comparatively sudden initial application of hydraulically-actuated disc calipers against rotor – not a problem, per se, but something to get used to compared to the gradual and tactile application attributed to upper-echelon rim brakes. There’s extra weight, too, and while the Domane SLR 6 Disc isn’t overly portly at 8.3kg, it’s certainly not light for a bike of at this price.
The wheels are tubeless-ready Bontrager Affinity Comp hoops. They reliable and roll well but aren’t going to set the world alight. The Domane SLR Disc frameset also has stacks of tyre clearance and Trek have taken full advantage, fitting 32mm tyres (the non-disc SLR gets 28mm rubber) for maximum comfort.
In truth, they also roll quickly - if you’ve been used to riding 23mm or 25mm tyres then you might expect them to be splashy and slow, but they’re nothing of the sort. Stick 60-70psi in them, and they’ll look after you all day long while instilling confidence in the bike's adhesion to the road on descents, as well as start the whole vibration-dampening chain in the bike.
Those wide tyres really add to the plushness of the bike, if also contributing a little to the slightly isolating ride quality. During the test period, I installed a set of Challenge Paris-Roubaix 28c tyres on the rims for comparison, blew them up to 80psi and immediately felt a sharper interaction beneath me. Either way, Trek have set this bike up really well for endurance riders, with comfort and speed coming hand in hand. Throw in the fact that 32mm tyres means you can point the Domane SLR off-road, and you're opening up plenty of possibilities.
Despite all that, it’s the handlebar that really shines. Thanks to the IsoCore rubber inserts, wrapped in carbon, you could install them on any bike and improve its vibration dampening qualities. The shape is as good at it comes, allowing easy access to all parts of the handlebar, while being very comfortable to hold during long days in the saddle. This is especially the case when you rest your hands on the tops, thanks to slightly wider shape for easier grip on rough surfaces. Throw in the comfortable Bontrager Affinity Elite saddle with titanium rails and shallow cutaway for perineal relief, atop a Bontrager-branded carbon seatpost, and your contact points are well-sorted.
The Trek Domane SLR 6 Disc is not only the most comfortable endurance road bike I’ve ridden, but it’s all-round quick and a fantastic looking machine with a smart spec. The rear IsoSpeed offers a tuneable range of compliance and the front IsoSpeed, combined with the IsoCore handlebar, looks after the front end admirably. Riders in search of a more agile and aggressive machine may be better suited by the Endurance Pro geometry - and we'd like it introduced as an option on this frame - but for endurance riders in search of a confidence-inspiring, disc-equipped machine which delivers comfort on tap then the Domane SLR Disc is among the best out there.
- Supremely comfortable; adjustable rear compliance
- Stable and relaxed geometry for endurance riding
- Very stiff and efficient when putting the power down
- Excellent spec; slick shifting, all-weather braking, plush tyres
- Some riders might find the plush ride a little isolating
- Not particularly light