TREK DOMANE SL 5 DISC
£2350 › The SL 5 pivots towards comfort
The only difference between this Domane SL 5 and the SLR 9 models used by the TrekSegafredo riders in the cobbled spring classics is the carbon fibre used to make its frame. While the WorldTour riders’ bikes are built with Trek’s 600 Series OCLV, this one is constructed from the slightly heavier 500 series. There’s no difference between the technology in the frames though, which means this SL 5 gets the same IsoSpeed decouplers that the pros rely on to smooth out the cobbled roads of Flanders and Roubaix.
The front decoupler comes in the form of a rocker-cup that replaces the top part of the head tube. It allows the steerer tube to flex forwards and backwards (but not sideways), and in so doing dampens the jolts from potholes and broken road surfaces without compromising the bike’s steering. There’s another decoupler built into the seat tube to give the rear end a similar level of compliance.
Since Trek debuted the technology in 2012, IsoSpeed-equipped bikes have won Strade Bianche, the Tour of Flanders and Paris-Roubaix so it’s fair to say that the system has proven itself in the most demanding of races.
Its compliance isn’t the only thing that marks out the Domane SL 5 as an endurance machine; its ride position does too. Our 58cm test model shares similar geometry to the Cannondale Synapse SE – its reach is a little less (38cm compared to the Cannondale’s 39.4cm) but not so much that it feels overly upright or cramped. But the comparisons to the Cannondale don’t stop there.
The Domane SL 5 is similarly smooth and stable over the most dreadful road surfaces and, thanks to its confidence-inspiring grip and wonderful balance, it’s able to descend and tackle challenging corners especially well.
All but the most extreme gravel tracks fall well within its grasp
Sadly, like the Cannondale, the Domane’s wheelset takes the edge of the experience, particularly when it comes to climbing. While we’re impressed by the SL 5’s generous tyre clearance, the alloy Affinity wheels and the wide 32mm tyres (there’s clearance to go wider if you wish) simply kill off the bike’s liveliness when the road ramps up.
The rest of the Domane’s spec is hard to fault, however. It gets a full 105 groupset, which works as well as we’ve come to expect, and its disc brakes have plenty of power and feel (even if the rather basic rotors can get a little noisy after prolonged braking). Bontrager takes care of the contact points, with a narrow but comfortable Arvada saddle and Comp VR-C handlebar thickly wrapped with topquality rubberised tape.
The Domane is the heaviest bike in this test, weighing in at 9.63kg, which further explains its sluggishness uphill. Its weight and climbing prowess could be slightly improved by running narrower tyres without tubes, but anything you gain by making this change might come at the cost of its descending and cornering performance.
As it stands, the combination of Domane’s decoupler suspension system and generous rubber means this bike can contend with far more than just roads. Cobbles, towpaths, trails and all but the most extreme gravel tracks fall well within its grasp. It’s just a shame that this all-road prowess has come at the expense of its climbing ability.