The Takeaway: Trek’s best road bike gets faster, lighter, quicker, and better

  • Frames are 300 grams lighter
  • Slight aerodynamic improvements
  • Compatible with any bar and stem

Price: $3,500 (SL 5) to $13,200 (SLR 9 eTap, tested)
Weight: 19.7lb. (SL 5) to 16 lb. (SLR 9) 16.8 lb. as tested (SLR 9 eTap 52cm)

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Well, we knew this one was coming. After Elisa Longo Borghini won the 2022 Paris-Roubaix Femmes aboard a Trek bike that looked nothing like the third generation Domane Lizzie Deignan used to with the 2021 edition or any other Trek, it was clear a replacement for the excellent Domane road bike was in the works. That bike, the fourth generation Domane (AKA Domane Mk. IV) arrives today. Literally—some models will be available to buy today. Spoiler alert: It’s awesome.

Trek Domane MK.4 Gallery
trek domane generation four

Trek Domane Generation Four—What is New

My biggest knock against the third-generation Domane was the weight. It was an excellent and feature-rich bike but a little hefty. So, I am happy to report that one of the most significant changes to the fourth generation frame is it is lighter by about 300 grams (more than half a pound. A large part of the weight savings came from simplifying the bike’s signature rear IsoSpeed Decoupler and eliminating the IsoSpeed Front system that debuted in the previous generation Domane.

When asked why Trek eliminated IsoSpeed Front, Jordan Roessingh, director of road bikes, stated that much of the system's benefit—which never offered the same compliance improvement as rear IsoSpeed—was made redundant by riders' increased adoption of higher volume tubeless tires run at lower pressures. Combined with the system’s weight penalty, Trek decided the juice was not worth the squeeze and punted IsoSpeed front into the dustbin of history.

Meanwhile, at the rear, Trek removed the adjustment from the SLR’s top tube IsoSpeed. All frames now have fixed compliance. Reggie Lund, a design engineer at Trek, said that it found, “A lot of our riders were never taking advantage of the adjustability on the previous generation bike,” so they decided to remove the feature which simplified and lighted the frame. Roessingh stated that the new Domane’s fixed compliance is in line with the previous generation SLR’s IsoSpeed set to the most compliant position.

trek domane generation four
The seatmast is gone, replaced by a (D-shaped) seatpost.
Matt Phillips

SL-level frames also see a change to their rear IsoSpeed system. Trek has multiple iterations and generations of IsoSpeed. While third-generation Domane SLR frames had adjustable top tube IsoSpeed, third-generation Domane SL frames had non-adjustable seat tube IsoSpeed. SL and SLR fourth generation Domanes get the new non-adjustable top tube IsoSpeed.

Roessingh said that one of the drawbacks of the third-gen Domane’s non-adjustable seat tube IsoSpeed was that the system got more rigid as the seat tubes got shorter. In short, smaller and likely lighter riders experienced a rougher ride than larger riders. Top tube IsoSpeed eliminates this compromise and lets Trek tune compliance per frame size, said Rosseingh, so all riders experience similar levels of comfort.

Another signature feature of carbon framed Domane models that went to the dustbin was Trek’s No Cut semi-integrated seat mast. Instead, all models now use a seat post, although a proprietary D-shaped post instead of being round. Thankfully, Trek offers two lengths (280 and 320mm) and two offsets (five and 20mm) to help riders dial in fit. The seatpost clamp hides under a snap-on cover on the top tube, which helps clean up the lines of the new Domane.

Another way Trek cleaned up the Domane’s appearance is with a new stem with a cap that hides the hoses and housing before they enter the frame through the upper headset cover. But while the bike appears to have fully integrated routing, you can swap stem lengths without pulling the hoses or housing. The bike is compatible with a standard handlebar, and riders can use standard stems. However, if you want to install a standard stem, you will need to acquire a different upper headset cover from Trek, and you will probably want to zip-tie your hoses and housing together underneath the stem.

Trek’s Domane stem comes in sizes 60 to 130mm in minus-seven degree rise and 60 to 100mm in plus-seven degree rise. The faceplate features a single bolt mount for a computer/light/camera. Unfortunately, the Domane stem’s one-bolt mounting standard is different from Trek’s one-bolt mounting system for the Madone and Emonda and also different than any of the other stems with this feature (3T, Cervelo, Fizik, Specialized, Felt, Easton).

trek domane generation four
The Domane’s stem provides integration, but the bike is compatible with standard stems.
Matt Phillips

Trek also states that the new Domane is more aerodynamic than the previous generation due to the updated shape of the fork, downtube, seat tube, seat stays, and more-integrated cables in the front. However, Trek did not provide any data on the aerodynamic improvements. When I asked Roessingh for time or watt improvements, he told me, “I don’t think we have a specific claim other than saying we do know the bike is faster. But it’s not a huge amount so it’s not a claim we’re labeling as one of the headlines of the launch.”

One small new feature added to the Domane is a mount in the top tube for a feed bag. What has not changed is the Domane has clearance for up to a 38mm tire, hidden fender mounts, the threaded (T47) bottom bracket, and the in-frame storage accessed through the hatch in the downtube.

SL and SLR frames are compatible with mechanical drivetrains. But, there is a catch outlined in Trek’s FAQ, “The frame does not have a front derailleur housing stop, which means that you are limited to front derailleurs with a built-in stop, like Shimano toggle front derailleurs.” That means the frame is not compatible with SRAM or Campagnolo mechanical-shift drivetrains.


Trek Domane Four—SL Versus SLR

There are two grades of Domane frame: SL and SLR. According to Roessingh, “SL and SLR are essentially identical from a feature set perspective and frame shape perspective.” The biggest difference is the carbon: The SL uses Trek’s “500 Series” carbon while the SLR uses “800 series” carbon. That material difference results in a 200-300 gram reduction in frame weight. According to Trek, this puts the SL frameset at 2,500 grams and the SLR frameset around 2,200 grams.

trek domane generation four
The RSL edition of the Domane doesn’t get the burrito smuggler.
Matt Phillips

Trek Domane Four—RSL for the Racers

Although Trek’s professional racers ride a Domane in some events, typically the cobbled classics, they do not ride the standard frame. Instead, they use the Domane RSL (Race Shop Limited). It is the frame ridden to victory in the 2022 Paris-Roubaix Femmes by Elisa Longo Borghini, and it has a few notable differences from the mainline frame.

The primary distinction is fit. The RSL fame is much lower and longer than the SL and SLR Domane. Using a 56cm frame as an example the RSL’s reach is 21mm longer (395 versus 347mm) while the stack is 43mm shorter (548 versus 591mm). The RSL also has a much shorter trail length (51mm compared to 61), likely because of the increased weight the RSL’s geometry places on the front wheel.

Other changes include eliminating the top tube bag mounts and in-frame storage hatch—you do not need those things when you have a fleet of team cars behind you—and the fender mounts. These changes help shave weight off the frame compared to the standard Domane. The RSL frame also has less tire clearance—its maximum tire width is 35mm instead of 38mm—but will fit larger chainrings (RSL: 2x 54/40, 1x 54T; SLR and SL: 2x 52/36, 1x 50T) than the SL and SLR models. Another noteworthy difference: The RSL is only compatible with electronic shifting.

Trek only offers the RSL as a frameset ($4,200) and only in sizes 52 to 60cm, four fewer sizes than the mainline frame. Claimed frameset (frame and fork) weight is 1600 grams for the RSL. On paper, that makes the RSL a whopping 600 grams lighter than the SLR. But when I fact-checked that weight delta with Roessingh, he told me, “The way we measure ‘frameset” weights in those metrics isn’t apples to apples. It includes a bunch of hardware and components. The RSL frame weight is only about 100g lighter than the SLR’s.”


Trek Domane Mk.IV—Geometry

Most of the Mk. IV Domane models carry forward the Mk. III’s endurance geometry with no changes. It is a shorter reach and a taller stack fit, with a longer wheelbase and mellower handling than a race bike. Trek offers nine sizes, from 44 to 62cm.

domane 4 sl slr geometry
Domane SL and SLR geometry
courtesy

The RSL version previously mentioned features a lower and longer fit race fit that is even more aggressive than the Madone and Emonda race bikes with the brand’s H1.5 geometry. The RSL is only offered in five sizes, from 52 to 60cm.

domane 4 rsl geometry
Trek Domane Four RSL geometry numbers
courtesy

Trek Domane Mk.IV—Builds, Prices, and Weights

trek domane four

Trek’s rolling out the new Domane with 11 models: five SL builds priced between $3,500 to $7,500 and six SLR models priced at $8,000 to $13,200. Only one model, the $3,500 SL 5, has a mechanical shifting drivetrain (Shimano 105); all the rest have electronic drivetrains from Shimano and SRAM. The SL 5 is also the only 11-speed bike; the rest are 12-speed.

All models come with Bontrager tubeless-ready wheels and Bontrager’s R3 folding-bead, tubeless-ready tires in 32mm.

Claimed weights start at 8.93Kg (19.7 lb.) for the SL 5, with the lightest complete bike coming in at 7.25kg (16 lb.). One interesting note on prices and weights: For the same relative equipment level—Ultegra Di2 versus Force eTap AXS—most Shimano-equipped bikes are less expensive and lighter than the SRAM-equipped bikes. There is a big “but” because all SRAM-equipped Domanes from the SL 7 eTap and up have power meters while the Shimano builds have standard cranks. The other exception is the SL 6 (Shimano 105 Di2) and SL 6 eTap (SRAM Rival eTap AXS)—the Shimano bike is $600 cheaper but slightly (10 grams) heavier.

As always, the Domane will eventually, though not immediately, find its way into Trek’s Project One customization program for riders who want to pick their parts and paint. Trek also offers the SL ($2,499), SLR, and RSL (both $4,200) framesets for purchase.

trek domane generation four
The seatpost clamp hides under a snap on and magnetic cover.
Matt Phillips

Trek Domane Mk.IV—Ride Review

Trek’s Domane has been a favorite of mine since the first generation, but the third generation was flat-out amazing. Comfortable, practical, and fun, it had most of the speed of a race bike without the bullshit that makes race bikes so limited and limiting. It fits big tires! You could run any bar and stem! It could store a burrito in the downtube! And it was fast.

So when Trek told me they were sending me the new, fourth generation, Domane I hoped and prayed that they found a way to make it better without messing up what made it so great. And friends, my hopes and prayers were answered because riding the fourth generation Domane was like reacquainting with a dear old friend, but one who lost a bunch of weight and now goes to therapy. Because this bike is everything the gen-three Domane was, but better.

You can read what I said about the third-generation Domane when I reviewed it and when I wrote it up as our 2020 Bike of the Year and take all of the good stuff and apply it to the new, fourth-generation Domane. But my complaints about it being a little heavy are gone. And with the weight reduction, the gen-four Domane unlocks new performance levels.

The biggest difference is the new bike is quicker, snappier, and just flies. When you hear someone talk about a comfortable road bike, it usually suggests a bike that is squishy and slow feeling. But when you get on a bike that is fast, quick, and communicative but also floats and coddles the rider like a newborn baby, well, that is a special bike. And that is what the new Domane is: Special. A great bike made better. A bike for the modern road rider: Freaking fast, wonderfully comfortable, and oh so practical.

trek domane generation four
You need to look closely, but the Domane can be fitted with mudguards.
Matt Phillips
Headshot of Matt Phillips
Matt Phillips
Senior Test Editor, Bicycling

A gear editor for his entire career, Matt’s journey to becoming a leading cycling tech journalist started in 1995, and he’s been at it ever since; likely riding more cycling equipment than anyone on the planet along the way. Previous to his time with Bicycling, Matt worked in bike shops as a service manager, mechanic, and sales person. Based in Durango, Colorado, he enjoys riding and testing any and all kinds of bikes, so you’re just as likely to see him on a road bike dressed in Lycra at a Tuesday night worlds ride as you are to find him dressed in a full face helmet and pads riding a bike park on an enduro bike. He doesn’t race often, but he’s game for anything; having entered road races, criteriums, trials competitions, dual slalom, downhill races, enduros, stage races, short track, time trials, and gran fondos. Next up on his to-do list: a multi day bikepacking trip, and an e-bike race.