Trek Domane SLR 9

Remember twanging rulers on desks at school? The shatterproof plastic ones were best. You could create some great comedy noises, altering the pitch by how far along you held it and even sliding it mid-twang for a different kind of sound altogether.

Why, you might ask, am I wittering on about schoolboy classroom antics? Well, oddly that’s what comes to mind when I think of describing the way Trek has designed the seat tube of its new Domane in order to offer tuneable comfort. 

For the record it doesn’t make any twangy noises, but the seat tube is split in two below the IsoSpeed decoupler (where the seat tube bisects the top tube), with a movable wedge sandwiched in between. Loosening the clamp bolt, which also doubles as one of the bottle cage mounts, allows you to reposition the wedge further up or further down the seat tube, effectively altering the anchor point according to your comfort requirements. At its lowest fixed point – nearest the bottom bracket shell – you get the maximum vertical compliance, like having more of the ruler overhanging the desk. Trek claims this provides 14% more vertical flex than the old Domane. Slide it all the way to the top and you get a noticeably less forgiving back end.

Softly softly

Having tested two previous versions of the Domane myself – the original release and the disc brake version - I’m in a strong position to assess this new design and make direct comparisons. I would start by contesting whether the new design is only 14% more vertically compliant. I would have said it was at least 20% better. It’s a visible difference to the old Domane, and when you’re in the saddle and hammering over rough ground it’s an appreciable benefit that’s a real boon for this new bike.

Everything from even the slightest road buzz feels better dissipated, but it’s the really big thuds where I was truly wowed. Hit a sharp-edged crease in the road surface or a speed bump at pace and you can feel the seat tube flex beneath you when on the softest setting.

The difference between the two extremes is really noticeable, and I’d agree that you can set this new bike stiffer than the old model. And of course you have everything in between to fine-tune to your heart’s content. I even kept a 4mm hex (with preset 5Nm torque key) in my jersey pocket on some rides to be able to quickly pull over and make a change, which, since you ask, takes only a matter of seconds.

But I found myself wondering – why bother? I’d put the wedge into a firmer setting and pedal off, but no sooner had I noticed the stiffer sensation than I would be inclined to stop again and switch it back to the softer end of the scale. The reason is simple: why pass up the chance to have a lovely smooth and comfy ride feel when there seems like absolutely no real downside to running in such a soft setting? While Trek claims the stiffer setting marginally preserves power, it doesn’t feel squidgy, like you’re sat on an exercise ball, and as I said, you only really notice it working when you’re thankful for it. All the while, pedalling performance seems to be almost entirely unaffected. It’s a real triumph in terms of design. 

OK, the Domane doesn’t whip up to speed quite as quickly as the Emonda (Trek’s super-svelte racer) or whizz along with the poise of the Madone (Trek’s aero road beast) but it’s no slouch and I was never left wanting. Our 56cm test bike was a smidgen over 7kg, partly thanks to Sram’s super-light Red eTap wireless shifting, which was flawless throughout this test.

Bontrager’s Aeolus 3 D3 wheels are also superb, bringing another significant positive to the build, although it was disappointing that Trek didn’t see fit to make the most of their tubeless compatibility in that the bike came fitted with standard clinchers - I’ll come back to the tyres later. Overall, it’s hard to fault the Domane’s performance, especially given it leaves both its forebears out of sight in terms of comfort. 

Back to front

While all discussion thus far has been focused on the rear end, there’s a lot going on up front too. Where the old model was criticised (and I agree) for feeling disjointed, in that the front end comfort couldn’t match the compliance of the rear, Trek has really worked on a solution for this new bike.

The IsoSpeed decoupler that has proved so successful in facilitating only the desired amount of flex at the rear of the bike has been re-engineered slightly to apply the same ideology up front. 

In short, the decoupler at the front end cradles the upper headset bearing to allow the steerer tube to flex front to back while maintaining lateral support. I’ll start by saying it’s nowhere near as effective as the rear, so
there remains some disparity, plus its effectiveness does seem to be dependent on the stem length (a longer stem has a lot more leverage, so will flex the steerer tube more), but it’s a step in the right direction.

In any case I’m not sure I would want the bars to feel as fluid as the seat tube does, given the potentially disconcerting feel that could arise with too much movement. It’s already enough that the design means there’s always a slight sensation akin to the presence of a loose headset and the occasional audible clunk to get your head around.

However, it does take the sting out of impacts and the handlebars themselves add to the vibration-absorption with newly developed technology from Bontrager. The Pro Isocore bar has a thermoplastic elastomer layer sandwiched between the carbon layers, which it claims reduces vibration by 20%.

The combined effect of these two new features up front is a noticeable step up in comfort compared to the old Domane, but I feel this area still needs a little refinement. Just as the second generation of the bike’s rear has moved on for the better, I think Trek will gradually be able to improve how the front end reacts too, and who knows – maybe even make this user-adjustable at some point in the future too.

Trek recommends a maximum 28mm tyre width (fitted as standard), but I was able to squeeze in a 30mm Challenge Strada Biancha open tubular. Admittedly clearance was tight under the Bontrager direct-mount brakes, but it was acceptable for all but a horribly grubby ride where dirt did start to accumulate and rub.

Running with 30mm tyres at 85psi made this bike the closest thing I have ever experienced to the magic carpet ride that many manufacturers have touted in their marketing blurb but few, if any, have ever delivered. 

I don’t like – or agree – with the term ‘do it all’ bike (who only wants to own just one bike anyway?), but Trek has at least realigned my thinking a bit, and certainly sets the bar high with the new Domane. There wasn’t much this bike couldn’t do. I even rode it on rocky mountain walking trails in the Dolomites up to over 2,000m (which you can read about soon). As I write, industry rumours are afoot of a response from Specialized, most likely with a revamp of its renowned Roubaix model (as yet unconfirmed), but I think even ‘the Big S’ will have its work cut out to top this Domane.

Spec