Sign up for our newsletter


Trek Domane SLR

Jordan Gibbons
26 Apr 2016

The new Trek Domane has an adjustable rear IsoSpeed, new front IsoSpeed and new IsoCore handlebars all in the name of versatility.

Trek wasn’t the first bike brand to use rear suspension in its frames but it’s the only one that can claim real success. The original Domane won the Strade Bianche, E3-Harelbeke, Tour of Flanders and Paris-Roubaix all under the power of Fabian Cancellara, but it has always suffered from accusations of feeling unbalanced. The rear end of the frame was as comfortable as they come, thanks to its IsoSpeed Decoupler,  but the front end felt harsh in comparison. The new Domane SLR hopes to change all that.

Trek has taken the lessons it learnt from adding a suspension unit to the rear of a frame and repeated that at the front end. 

‘Ever since the first Domane, people have been asking us to put an IsoSpeed in the fork,’ says Ben Coates, Trek’s road product manager. ‘Eventually, enough people kept going on about it that we just thought, “Why not?”’

The front IsoSpeed works by isolating the upper headset bearing from the frame. The decoupler sits inside a cup that is attached at two points either side, with the bottom cup remaining fixed. This allows the upper headset bearing to rock back and forth, but not side to side. This motion allows the steerer tube to flex in a controlled manner and Trek claims this allows for a 5-9% increase (depending on stem length) in movement compared to the previous Domane, which Trek suggests offers 10% more comfort over a traditional road frame.

Trek Domane SLR 9 IsoSpeed

The rear end has also seen some changes, but in the name of adjustability rather than outright comfort. The seat tube is now made of two separate pieces that are joined at the base, behind the lower bottle boss, with a small slider in between. With the slider at the bottom, the two seat tubes are forced apart allowing for a big range of movement at the saddle – Trek claims on its softest setting the new Domane SLR is 14% more comfortable than the previous version. Pushing the slider all the way to the top reduces the flex by approximately 25%, making it slightly stiffer than the original Domane.

‘Fabian has been invaluable throughout this whole process,’ says Coates. ‘He’s able to ride a bike and not only can he feel the difference between two different prototypes, he’s able to translate that into something we can understand and work with.’

Trek didn’t just rely on ‘feel’ to improve the bike, though. Cancellara rode a bike fully rigged with sensors over various stretches of the Roubaix cobbled sectors to gather information on how a frame reacts to the surface. Not content with that, Trek repeated the process back in the US.

‘We built our own 100m long strip of cobbles in the lab, so that we could measure exactly what happens to a frame in a repeatable environment,’ says Coates. ‘We took the results, altered the frame, then did it again and again until we found something we were happy with.’

Playing the angles

There are geometry changes in the frame, too. Some criticised the original Domane for being a little too relaxed, so Trek has made the SLR frame available in two geometries: Endurance and Pro Endurance. The Pro Endurance geometry has a longer reach and shorter head tube, while maintaining the same handling characteristics.
The Pro geometry is only available on 54-62cm frames however, as that’s the current range of sizes used by the Trek-Segafredo pro team riders.

Completing the comfort package are the new Bontrager IsoZone handlebars. Trek claims the average alloy bar deflects approximately 4.25mm when riding over rough surfaces, while the average carbon bar deflects approximately 3.85mm. The new IsoCore handlebar only deflects by 3.25mm, making it stiffer under load, however Trek claims it still isolates the rider from bumps. The IsoZone handlebar is ‘constructed with a continuous inner layer of a specialised thermoplastic elastomer encased in proprietary OCLV’. This plastic-carbon sandwich is said to reduce vibration felt at the bars by 20%.

The Domane SLR is available in both rim brake and flat-mount disc brake options, with the disc brake fork now upgraded to a 12mm bolt-thru axle. There have also been numerous more subtle changes, such as a switch from regular calliper brakes to direct mount to increase tyre clearance up to 28mm (or 32mm on the disc option). There is also a ‘control centre’ in the down tube, which is just a fancy way of saying ‘Di2 box’, similar to the one found on the Madone.

Even with all these additional features, advances in the carbon fibre used to make the frame mean the weight remains the same, with the Sram eTap equipped SLR 9 weighing just 6.76kg. 

Look out for a review of the SLR 9 in an upcoming issue of Cyclist.

Page 1 of 2Trek Domane SLR

Read more about:

Page 1 of 2Trek Domane SLR