New 2023 Trek Domane ditches adjustable IsoSpeed Decoupler

Sam Challis

8 Sep 2022

Trek says the new bike is lighter and more aero as a result, but no less comfortable

Trek has officially launched a new version of its Domane endurance platform, hot on the heels of its new Madone.

A new RSL version of the frameset – which now sits on top of the existing SL and SLR tiers – has been raced in the WorldTour for several months, with Trek-Segafredo’s Elisa Longo Borghini winning the 2022 edition of Paris-Roubaix Femmes aboard it.

It appears that Trek has pushed the design further in several areas that on the face of it would seem mutually exclusive: the bike is said to be lighter and faster, yet offers large tyre clearance and more mounting points too.

The IsoSpeed Decoupler has been simplified at the rear, becoming non-adjustable to make it lighter, and the front IsoSpeed device has been ditched entirely.

Trek says that the new Domane SLR frameset is 300g lighter than the previous generation Domane. This is despite the new bike using ‘Kammtail Virtual AirFoil’ tube profiles informed by the new Madone to make it the fastest Domane Trek has yet made.

The SL and SLR versions of the frameset are the same in shape, but different in material: the SLR uses Trek’s 800 Series OCLV carbon composite while the SL uses the less premium 500 Series OCLV.

Trek will offer five SL builds, six SLR builds and three frameset options, with prices ranging from £3,300 to £12,500. The new Domane is said to be available within the next couple of weeks.

New Trek Domane: 10 things you need to know

300g lighter frameset than previous generation
Said to be the fastest Domane Trek has made to date
Uses a smaller, lighter, non-adjustable rear IsoSpeed Decoupler
Available at SL, SLR and now RSL tiers
Trek’s 800 Series OCLV composite blend used for the first time in SLR tier
38mm tyre clearance with 6mm gap around the tyre
Now has integrated mudguard mounts
Includes down tube hatch storage and a top tube mount
11 specs available plus 3 framesets, in sizes from 44cm to 62cm
Prices range from £3,300 to £12,500, availability imminent

Expanded horizons

The Domane has always been Trek’s comfort-orientated road bike but in the fourth generation of the bike Jordan Roessingh, Trek’s director of road bikes, says the brand wanted the bike to introduce racier road performance, yet more off-road capability too.

‘We wanted it to balance light weight and speed with comfort and capability,’ he says. ‘We have the Madone and Émonda occupying the out-and-out race niches, but for routes where comfort is top priority the Domane is the best choice.

‘We see it as the other side of the coin to our Checkpoint gravel bike: that goes well on road, but is gravel-focused, whereas the new Domane goes well off-road, but is tarmac-first.’

Roessingh says the biggest priority – based off pro and amatuer feedback – was to save weight over the old generation of the design.

‘We wanted to make it more aerodynamic, and had the capacity to, thanks to our work on the new Madone. If we could make the bike faster as well as lighter, we knew we could make the Domane feel a lot better to ride.’

The last main development was to make it cleaner too – meaning sleeker tube junctions, a simpler IsoSpeed device, and internal cable routing.

In fitting retrospect considering Borghini won the latest edition of the Paris-Roubaix Femmes aboard the new Domane RSL, she and a few of her team riders were key figures in the Domane’s development, and tested prototypes on the sectuers of the race route.

‘Testing was done without us knowing how the frames were different to each other, says Borghini. ‘But in the end it was a unanimous decision on the best version.’

IsoSpeed Decoupler: Fewer, smaller, neater

The Domane was the bike that introduced Trek’s IsoSpeed Decoupler concept over a decade ago and versions of the device have been key features in a lot of the brand’s road and gravel bikes ever since.

The fourth generation Domane sees a considerable update on the design. Previous versions of the bike have used a headset variant as well as a tunable one in the seat tube, but the new Domane goes back to a conventional front end and makes the seat tube decoupler non-adjustable.

This follows the move made in the revision of the Madone aero bike, and means an adjustable Isospeed Decouple doesn’t feature in Trek's road line-up anymore.

‘The adjustability function wasn’t used enough to justify its continued inclusion,’ says Reggie Lund, the Domane’s lead design engineer. ‘It was just set-and-forget on the most comfortable setting for most people, so we simplified the design to make it lighter and easier to live with.’

As it isn’t adjustable now, the Decoupler can be much smaller and housed within the top tube, so the shape of the seat tube junction is a lot less complex.

Smoothing things out further, the seatpost clamp has been integrated into the system and is hidden under a magnetic cover.

Lund explains that the increase tyre clearance made it possible to ditch the front IsoSpeed Decoupler. ‘The capacity for larger tyres improves comfort to such a degree that it dwarfs what the front IsoSpeed device could offer,’ he says.

Diet Domane

Both the Domane SL and the Domane SLR save around 300g in their framesets despite the liberal use of aero tube profiles, meaning that although they are the lightest disc brake Domanes Trek has made, they are also the fastest.

‘We achieved these changes through a combination of several areas,’ says Lund. ‘The alteration of the rear IsoSpeed and removal of the front one helped shed weight and the switch to 800 Series OCLV composite was a contributor too. The new material and laminate designs saved are lighter, despite us updating the tube profiles to make them more aero.

‘The finishing kit topped things off – the Domane has a lighter, kamm-tail-shaped seatpost and integrated cockpit system.’

Cables from the levers now run neatly into a gulley under the stem created by profiled headset spacers and through an oversize upper headset bearing.

Endurance features

Along with the Domane SL and SLR’s endurance-focussed geometry, the official tyre clearances is about the only thing to remain unchanged on the new bike, staying at 38mm.

However that is with Trek’s recommended 6mm of clearance all around the circumference of the tyre, meaning if users are happy with less space between tyre and frame, truly wide tyres can be used without much hassle.

Though if slimmer tyres (up to 35mm) are fitted mudguards can be used with the bike, as it now has integrated mounts for them.

The down tube storage hatch concept is carried over from the from the previous bike and coupled with new mounting points for a bag on the top tube too.

For more information on the new Domane range visit trekbikes.com

Trek Domane Range overview

In total there will be a 11 specs for the new Domane – 5 available for the SL frameset and 6 available for the SLR frameset – plus SL, SLR, RSL frame kits available too. The RSL version of the frameset used the same frame as the SLR, but pairs it with a lighter fork.

Finishing components for all frame specs is predominantly supplied by Bontrager, with groupset and wheel choices being the main differentiators between the builds.

All bikes use 32mm tyres as standard and come with everything the user needs to set the bike up tubeless.

Claimed weights for a size 56cm Domane range from the £3,300 SL 5 at 8.93kg to 7.25kg for the £12,00 SLR 9.

The 6, 6 eTap, 7 and 7 eTap builds are largely duplicated between the SL and SLR framesets, so the main point of difference is around half a kilogram of extra weight. This disparity is a result of the heavier frameset and some small finishing kit differences.

Similarly, a given Shimano build is around 400g lighter its SRAM equivalent and on average £450 cheaper, but the SRAM eTap AXS builds (aside from the Rival equipped SL 6 eTap) feature power meters as standard.

In conjunction with the impressive spec range, the Domane will be offered in sizes from 44cm to 62cm, which is the widest size range Trek offers for any bike. The brand says it is its most popular bike so deserves with widest range of options.