Testing the Trek Domane 4.7 on the Sunshine Canyon climb just west of Boulder, Colorado.
First let’s get this out of the way: The mechanism at the seat tube junction of the Trek Domane is not some sort of road bike-specific suspension, it’s the IsoSpeed decoupler.
So what the heck is a decoupler, you ask? The answer (for our purposes) is that it’s the primarily reason why the Trek Domane 4.7 ranked highly with every tester who put this bike through its paces during our month long test session on the roads (dirt and paved) in and around the cycling Mecca that is Boulder, Colorado.
Simply put, this new-fangled gizmo (or whatever you want to call it) delivers as advertised, smoothing out rough roads without compromising pedaling efficiency. It’s not happenstance that cobbles killer Fabian Cancellara chooses to ride a fancier and more racy version of this bike not just at Paris-Roubaix and the Tour of Flanders, but any time he pins on a road race number.
It’s also not an accident that our test team loved this bike. “I would buy this bike no question,” said one tester. “The overall ride quality — especially on rough roads — is hard to beat at this price point.”
The other major factor in favor of the Domane 4.7 is its spec. Like nearly all the bikes in this shootout, it benefits from the precision reliability of an 11-speed Shimano Ultegra drivetrain. But unlike some of the other bikes in this round-up, the gruppo is complete. No swapping in substitute components (brakes, chainrings, etc), which is often done by product managers to help keep costs down.
“Shifting performance is predictable and reliable, just like Shimano always is,” said one tester. “In my opinion, it’s the best group you can ride on a $3,000 dollar bike.”
The decoupler mechanism allows the seat tube to float, pivoting on an internal axle where a pair of sealed cartridge bearings separate frame from axle. The whole mechanism acts as a sort of leaf spring. Meanwhile, the IsoSpeed fork has slimmer fork legs paired with rearward-facing dropouts, which are designed to better soak up road vibration and bumps without compromising steering precision.
So really, what the heck is a decoupler?
Take a gander at the seat tube cluster and you’ll see an interesting melding of shapes where the top tube splits just in front of the seat tube, then wraps around and splits, becoming the seat stays. This allows the seat tube to float, pivoting on an internal axle where a pair of sealed cartridge bearings separate frame from axle. The whole mechanism acts as a sort of leaf spring, which when combined with the subtle flex of the 27.2mm seatpost, conspires to take the sting out of rough roads.
“It was my favorite bike in the test,” said one tester. “It was so vertically compliant, which was really noticeable compared to the other bikes in terms of comfort.”
That comfort is further enhanced by what Trek calls its IsoSpeed fork, where slimmer fork legs pair with rearward-facing dropouts, which are designed to better soak up road vibration and bumps without compromising steering precision. Additionally an 1 1/8-to-1½ tapered steerer improves overall rigidity, while an oversized down tube and girthy asymmetric chainstays mated to a BB90 bottom bracket help maintain stiffness and responsiveness under hard pedaling.
Our test team put all this engineering and design to the proverbial test on the famed Boulder Roubaix course, a mishmash of rough wash-boarded dirt roads just north of Boulder. The main loop is a mix of rumbling flats, punchy climbs, and short, fast descents. It’s just the type of terrain this bike was designed for.
“Overall the bike had no problem soaking up rough roads,” reported one tester. “Occasionally the rear wheel wanted to move around a bit in really rough stuff, but it was very predictable and never scary. Washboards were comfortable, as the front end tracked straight and didn’t bounce around at all.”
This was achieved on a set of fairly pedestrian 25c Bontrager R2 tires. But what if you want to go wider? No problem. Like every bike in this test, the Trek Domane 4.7 passed our tire check test, which meant swapping on a set of 27c Challenge Paris Roubaix tires that actually measure closer to 30c.
The Trek Domane 4.7 passed our wide tire check test, and survived the brutal Rapha Continental Colorado race.
One of our testers even went so far as to ride this bike in the recent Rapha Continental Colorado, a 100-mile mixed surface death march of a race with upwards of 13,000 feet of climbing. To save some weight, he swapped on a set of HED C2 23mm wheels wrapped with 28mm Clement Strada LGG tires. Again, no problem.
“The tire switch provided a whole other level of confidence with this bike,” said our tester, who added he had no issue logging an 8-hour day on the stock Bontrager Affinity saddle. “It never felt out of sorts in the steep loose dirt roads. I always felt like there was more speed to be gained.”
If the Domane has a weakness, it’s as a pure uphill climbing machine. This 56cm roadster tipped the scales at just a shade over 18 pounds sans pedals, and some testers found it a little sluggish during seated uphill climbing despite its compact 50-34 chainring paired with an 11-28 cogset.
Parts spec certainly played some role in those sensations. House brand stem, bar, seat post and wheels are all places where weight could be shed. But the Domane 4.7 is not a whale by any means, and anyone who buys this bike will benefit from the knowledge that swapping on those lighter components down the road will net immediate and noticeable performance gains. “It might just have been tired legs,” said one tester. “But to me it felt a little slow when climbing seated.”
Check out the comparison chart below to see how the Trek Domane 4.7 stacks up weight-wise against the other bikes in this test.
It’s also worth noting that the Domane 4.7 is the only bike in this test with external cable routing, which depending on your level of mechanical aptitude may be a good or bad thing. It used to be that dealing with internal cable routing was an exercise in tested patience.
But as the local mechanic who helped us build up all these bikes noted, “Nearly all bikes are much better than they were just a few years ago in terms of internal routing. It can still be a little tedious to get cables through the chainstays, but really it’s pretty straight forward. That said, the external routing on this bike will definitely be a little easier for home mechanic to work on.”
Overall geometry is what Trek calls, endurance fit. The idea is that the bike retains a racy feel in terms of stiffness, but has a slightly taller head tube (17.5cm for a 56cm) that yields a more balanced and stable position, alleviating the potential for back pain. And indeed, like all the bikes in this test, position is more upright than say on a 4 series Madone (17cm, size 56cm), or even Trek’s newest road offering, the ultra-light Émonda (17cm for H2 size 56cm).
An elongated wheelbase further enhances stability. The Domane 4.7 in a 56cm measures 100.8cm, versus 98cm for the similar Madone and 98.3cm for the Émonda. Here’s a look at key geometry measures for all the bikes in this test.
Other notable features included the integrated chain keeper that’s mounted directly to the frame, and the fact that if you don’t like the predominantly white paint scheme, you can design your own Domane 4.7 via the company’s Project One customization platform (additional charges apply).
The Trek Domane 4.7 has a complete 11-speed Shimano Ultegra mechanical shifting group, and comes stock with a host of Bontrager components, including wheels, tires, bars, stem, and seatpost.
This was undoubtedly one of the top bikes in this test, delivering all the key features that should be part and parcel for an endurance road bike. While not the most nimble climber in the world, the Trek Domane 4.7 is comfortable and efficient whether slogging through an all-day ride on the flats, or rambling down a dirt road during a roubaix-style race or ride.