The Trek Domane 4.3 ridden, reviewed and rated
Trek Domane 4.3
Trek’s 4 series Domanes are the entry level carbon fibre frames of Trek’s unique articulated frame long haul bikes. Is the hinged frame all hype or a genuine advantage on gruelling rides though?
Frame and fork
Trek’s 4 series frames are the cheapest way to get a carbon fibre Domane. That means basic 400 series OCLV carbon fibre and riveted external cable guides compared to the lighter weaves and internal wires of the 5 and 6 series bikes.
Crucially the key elements of the Domane ride are all intact though. These start with the tall Endurance Geometry head-tube and the forward swept, turned wrist IsoSpeed fork that keep your head up and road vibration down.
The fork still uses a 1.125-1.5in E2 tapered head-tube to retain steering stiffness and the down-tube and top-tube are both very beefy and broad, finishing in an extra wide, asymmetric Press Fit 90 bottom bracket block.
It’s the top of the seat-tube that’s really interesting though, with two wraparound gussets hiding the unique IsoSpeed decoupler pivot.
This allows the seat-tube and seatpost to flex back and forward in isolation from the top-tube for extra smoothness in the saddle. From here the rear stays arc back and down very gracefully via a broad wishbone section.
Trek hasn’t just concentrated on the bigger features on the bike either as super neat removable eyes for rear mudguards on the dropouts and a built in spur for the Duo Trap computer sensor on the offside chainstay show.
Kit is based around a durable, dependable Shimano 105 set-up with a compact chainset and a wide range 12-30 tooth Tiagra rear cassette from the next groupset down. Brakes are conventional 105 too. Trek’s own brand Bontrager supplies the compact cockpit with extra fat bar tape wrapping and comfortable saddle on top of a carbon shafted seatpost.
The Bontrager rimmed wheels are very heavy though and, from experience on other bikes, upgrading the reinforced Bontrager tyres would make a big difference to performance. It also makes the 4.3 a full kilogramme heavier than most of the other bikes in the test.
If that sounds like we’re setting the Domane up for a fall, you’re wrong. We’ll admit that we kept scratching our heads at how such a significantly heavier bike, shod with such lumpen tyres, managed not only to keep pace with the other test bikes most of the time but also to be so enjoyable and enthusiastic to ride.
The short answer is that the ‘decoupler’ really does work remarkably well. There is definitely more backward and forward movement on this carbon framed version than on the cheaper alloy Domanes we’ve tested.
That can translate into a noticeable ‘rowing’ action when you’re grunting round a gear at slow revs. But while that sounds like a dynamic disaster, nearly all our testers found the motion actually helped smooth out pedal stroke and power delivery when tempo was tough.
It feels equally buoyant out of the saddle too and however much we tried to remain realistic about the real versus perceived effect of the way the frame was working underneath us, we all really enjoyed riding the Trek and never felt short changed swapping onto it on group test rides.
While behaviour under power is surprisingly good, the way the Domane does what it’s supposed to do – hoover up road shock – is genuinely in a different class to any other road bike we’ve ridden. Jump on the Domane and the staccato shock and rattle genuinely just melted underneath it. This made every rough patch the perfect opportunity to give back some of the pain that it sucked up on steep climbs – and don’t forget that this will become significantly better if you invest in top quality tyres or saved up for one of Bontrager’s tubeless wheelsets.
Better rubber would also let you take more liberties with the assured slack head-tube angle and long wheelbase handling of the Trek. That’s not to say it’s bad at the moment, as the forks are a lot more communicative than their smoothness would suggest, but you do need to get off the fat padded bar tops and into the drops to put enough pressure through the front tyre.
Hunkering down into the drop bars is also essential to fight into headwinds, but then this bike is unashamedly ergo rather than aero.
+ Unbelievably smooth ride over even the roughest surfaces
+ Sprung ride’s enthusiastic charm outweighs kit compromises
– As well as it hides its weight, there’s no escaping it on long climbs
– Gagging for a wheel and tyre upgrade to release more speed