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Trek Domane SL 5 Disc 2017 Review

January 16, 2017

The Domane range has been around for many years and continues to evolve past the traditional norm for endurance road bikes. It's a hugely popular model for Trek and the 2017 Australian line-up features 15 different models incorporating a Race Shop Limited edition, SLR, SL and S versions, disc and non-disc equipped options, and two aluminium versions.

We tested the Domane SL 5 Disc which features front and rear IsoSpeed technology, huge 32mm tires, flat-mount disc brakes, race-ready Metron Vision wheels and comfortable geometry. Trek has made the bold move of prioritizing wheels over drivetrains, with no better example than the model we tested. Read on to see if that decision is a good one.

  • Who’s it for: The everyday rider that wants more performance and doesn't want to make any after-market upgrades.
  • What we like: Impressive handling, serious smooth ride, upgraded Vision Metron wheels and 32mm tires.
  • What we don’t: Shimano 105 drivetrain at an Ultegra price.


fullpage trek domane sl 5 disc 2017 review endurance geometry

The Domane is positioned as Trek's endurance bike and so adopts the 'endurance fit', which has a longer headtube and shorter reach to put the rider in a more upright position.

A quick look at how the Domane stacks up against the Madone and Emonda and the endurance direction is obvious. For a 58cm frame, the headtube is 0.5cm taller, head tube angle almost 2 degrees slacker, chainstay length over a centimeter longer and the wheelbase 3cm longer, resulting in a taller stack height and reduced reach. All of this aims to put the rider in a more upright position and improve the stability of the bike.

fullpage Trek Domane SL 5 Disc review BikeExchange geometry chart

The Domane's 500 Series OCLV Carbon frame is stacked with features that not only compliment the endurance geometry but ensure the bike still has plenty to offer those wanting to ride hard. 'OCLV' carbon is Trek’s patented carbon fibre process and comprises of five 'series'; 700, 600, 500, 400 and 300. The 700 series is reserved for Trek's top-tier creations, while the 600 series features on 'SLR' Domane versions and the 500 series featuring on 'SL' versions.

The foundation of the Domane range is Trek's proprietary 'IsoSpeed' technology which first started with the Domane and has since made it's way onto the aero Madone and even the Procaliber hardtail mountain bike. The idea of this technology is to separate the seattube from the toptube, allowing for greatly increased flex (compliance) in the seat tube, all without sacrificing resistance from twist (flex). For 2017, the Domane sees the IsoSpeed decoupler technology added to the front of the bike, this allows the steerer tube to move independently from the head tube reducing the impact from big bumps in the road. Trek say this new technology 'delivers an additional 10% of front-end compliance over a traditional road bike'.

As important as IsoSpeed is in the rear of the bike, it could be argued that having it in the front is even more important due to the impact felt through your hands, arms, shoulders and how much quicker they will fatigue compared to your legs. In addition, improving handling and compliance at the front should be the priority as it will have the biggest impact on control and comfort of the bike. The introduction of IsoSpeed to the front for 2017 should create a better marriage between the front and rear of the bike compared to previous models with only rear IsoSpeed.

fullpage trek domane sl 5 disc 2017 review front isospeed

fullpage trek domane sl 5 disc 2017 review rear isospeed

Disc brakes are found on the majority of the Domane range, flat mount Shimano RS505 hydraulic disc brakes the choice for the SL 5. Flat mount calipers are the new standard for road bikes, providing a clean, compact and lightweight option that doesn't sacrifice on power or control when compared to earlier road disc brakes that were borrowed from mountain biking. The disc rotors are 160mm in diameter and provide plenty of stopping power and dissipate heat well to avoid excess build up on long descents.

fullpage trek domane sl 5 disc 2017 review disc brakes

To accommodate the disc brakes, 12mm thru-axles are used at both wheels. These have a larger diameter than a standard quick release and improve stiffness and steering as a result. It also makes tightening the wheel into position exceptionally easy, doing away with the fiddling and having to know exactly how tight to do the quick release before closing. It also means a flush lever position every time.

The Domane's bottom bracket is using Trek's BB90 system, it's a lightweight option that creates a huge bottom bracket area that allows for large tube shapes and transference of power. Earlier generations of bikes using this bottom bracket system suffered from creaking, however, a new bearing design means this noise should be a thing of the past. This test sample remained perfectly silent during the test period.

There are plenty of other features that come standard with the SL 5: hidden mudguard mounts, internal cable routing and an integrated chain keeper for the front crank. Like other premium Trek road bikes, the SL 5 is DuoTrap S compatible, meaning that the wireless cadence and speed sensor (sold separately) sits neatly tucked within the left chainstay. A Ride Tuned seat mast completes the list of extensive features, Trek uses this in favor of a traditional seat post to best complement its IsoSpeed technology. Trek' reasoning here is that traditional seat posts placed inside the seat tube create a harsh ride by effectively stiffening the seat tube.

fullpage trek domane sl 5 disc 2017 review 2

With everything that the SL 5 has on offer, it's worthwhile pointing out two features that are exclusive to the Domane SLR range and not featured on the SL; the new rear IsoSpeed with customizable rear compliance and the IsoCore handlebar.

The new IsoSpeed features a twin seat tube design that allows you to customize the rear end stiffness by sliding a spacer that separates the seat tube and integrated seat must. This adjustment allows you to soften or firm up your ride by as much as 9%, allowing you to transition from a stiff race bike to an all-day epic just by shifting a spacer.

The IsoCore handlebar is also exclusive to the SLR range, the intention of the design is to dampen road vibration felt by the rider, while the front IsoSpeed takes care of the bigger hits. You can see an overview of the full 2017 road range from Trek that breaks down each model with specification and price, including the Domane, Madone, Emonda, Silque, Lexa and 1 series.

There's no shortage of R&D that has gone into the Domane frameset, but like any complete bike, it's a sum of all the components and how it rides in the real world that matters most. Let's delve in.


fullpage trek domane sl 5 disc 2017 review bontrager tyres

Look to nearly any major brand bike on the market, and you'll see plenty said about the frame and then the level of drivetrain components equipped. In reality, no component makes more of a difference to the ride quality, performance and general quality of a bike then the wheels, and yet, it's a part so often overlooked in a bike purchase. Trek have made the interesting decision to provide upgraded wheelsets on selected models for 2017 for those riders that are looking for added performance without having to make an aftermarket purchase.

In this case, Vision Metron 40 disc LTD wheels are used that instantly catapult the SL 5 into the performance bike category. As the name suggests, the carbon wheels are 40mm deep and feature CNC machined aluminium hubs laced with high-quality aero bladed spokes (24 front / 28 rear).

The 25.5mm width rims have a 23mm minimum tire requirement but come standard on the SL 5 with enormous 32mm Bontrager R2 Hard-Case Lite tires that we found virtually bomb proof. We measured the tire width as 31.7mm on the front and 31.8mm on the rear at 70psi.

A claimed weight of 1,675 grams for the pair puts it up there with the lightest of disc road wheel options on the market, even when comparing to major (and high priced) brands such as Enve, Zipp and Mavic.


fullpage trek domane sl 5 disc 2017 review shimano 105

Shimano 105 is the drivetrain of choice with a traditional 50/34 compact front crankset, paired with an 11-32 11-speed cassette of the rear. Many people would be surprised with 105 at this price point, where Ultegra is near expected.

Trek have taken the brave approach and clearly focused on ride quality and how well the bike performs for the money, not how it ranks on paper. The first upgrade for most is the wheelset, which Trek have done at the expense of the drivetrain. In this instance, Trek has taken a chance by putting the frame and wheels ahead of the drivetrain, it's a decision we agree with and time will tell if it catches on.

Ride Impressions

fullpage trek domane sl 5 disc 2017 review gravel

I mentioned that Trek has focused on ride quality over how well the bike ranks on paper, and the outcome is a huge success. This bike is the most comfortable I have ever ridden and not only in terms of fit but also in terms of smoothness on the road and the stable and predictable handling it provides.

The 32mm tires are a revelation and not as far removed from a performance point of view as the skinner tyre options as you might think. Prior to riding this bike I would have said running 28mm tires is the largest I would go, but I'm now seriously reconsidering that train of thought. The comfort is unquestionable and performance at high speed wasn't lacking as much as I thought it would. I felt at high speeds, 40kph and beyond, they required more work to keep rolling than my usual 25mm tires but aside from that they were every bit as good. They smoothed out road vibration like nothing I've ridden before and as mentioned, were indestructible. A clear point to make is that most frames and wheelsets aren't built for such large tyres, so 32mm tires aren't likely to fit your current road bike.

fullpage trek domane sl 5 disc 2017 review tyre clearance

As well as being able to accommodate almost cyclocross sized tires, there's no doubt a large portion of the bikes performance was due to the wheelset which performed exceeding well. The larger tire volume and extended Domane geometry made things a little harder to get going but once rolling they carried speed well, weren't adversely affected in strong crosswinds and were responsive in and out of corners. There was no obvious flex during sprint efforts and at below 1,700 grams, they were hardly noticeable during any hill efforts.

While I thought the Domane would be comfortable, I didn't expect it to handle as well as it did. From the outset, I thought dropping it into corners would feel slow and require significant effort to pull it out at speed but this wasn't the case. The handling is rather sharp for an endurance bike and on more than one occasion I came out of the corner thinking I could have gone so much harder. I progressively pushed harder and harder into corners and while the bike as a whole lacked a little agility, it felt balanced, making cornering at speed comfortable and inspired confidence to go harder next time.

fullpage trek domane sl 5 disc 2017 review aerial view

It's at this point we need to give some kudos to the team at Trek for providing comprehensive geometry charts on their website. Trek's geometry charts provide the rarely sighted 'trail' and 'offset' figures which give a great insight into the handling of a bike and might explain the impressive results. The Domane comes in at 6cm of trail which is a little greater than the standard for most ride bikes, providing a nice balance of stability and responsiveness. The fork offset is also slightly larger to account for the slacker headtube angle, explaining why, despite being an endurance bike, the Domane provides impressive handling. Check out BikeExchange's guide to geometry charts for more on trail and how it affects bike handling.

The IsoSpeed technology I found less noticeable on this bike than two previous Domane's I've ridden. The use of the larger tires nullifies much of the normal road vibration you feel, as a result, there is less for the IsoSpeed decouplers to do. The only time I was obviously aware of them was when cannoning into a pothole while out of the saddle with the majority of my weight over the front wheel. I felt some movement at the front of the bike but it wasn't what you might expect to feel with a loose headset, instead, it felt rather soft and plush.

I found the IsoSpeed is most noticeable when there is some form of jarring involved, while the tires handle the majority of the lesser road vibration. It's for this reason, I don't feel you're missing too much by not having the 'new' rear IsoSpeed. The additional compliance is hardly required and if it were my own bike, I'd shift that spacer to firm up the ride as much as possible.

The braking performs as expected which is to say flawlessly. Hydraulic braking is smooth, requires little finger effort and is much more consistent than rim braking. My chief complaint with hydraulic disc brakes has always been the larger hoods which I've never been able to find a comfortable position. While I still found this to be the case on the SL 5, the size is gradually reducing as development continues and so was less noticeable than previous hydraulic disc brakes bikes I've ridden.

fullpage trek domane sl 5 disc 2017 review 1

And so that leaves the drivetrain. As mentioned, most people looking at the price point of this bike would expect Ultegra, possibly even Ultegra Di2 at a stretch, but none of those bikes would come equipped with a quality wheelset like the Vision Metron 40's. And therein lies the conundrum, do you prioritize drivetrain over a wheelset or the other way around? The 105 groupset is considered the workhorse of Shimano's stable; durable, reliable, and the company's first real step into the performance orientated groupset market. The shifting is quick, precise and more than qualified to meet the demands of most of us. If you are looking to upgrade, it also has the ability to swap individual parts with Ultegra and Dura-Ace. And so the cost of upgrading a wheelset versus a groupset is worth consideration when weighing up the value proposition of Trek's - frame > wheelset > groupset - prioritization.

Looking past the name on the drivetrain, the compact crankset paired with the large ratio cassette is the perfect choice for endurance bikes. It provides a huge range for all day riding, and even greater range than standard cyclocross bikes if you fancy taking it on gravel roads. The 50/11 doesn't leave you short on faster road rides either which makes this ratio a great option.


fullpage trek domane sl 5 disc 2017 review 3

Trek have invested heavily in their R&D department for many years and the fruits of their labour are clearly evident in the Domane frame. Ride quality is paramount and that shone through in my testing. From a buyer point of view, it will be interesting to see what is made of the decision to upgrade the wheelset at the expense of a higher-tier drivetrain. Either way, that shouldn't draw too much attention away from what is a well-executed endurance bike that is capable of so much.

The Trek Domane SL 5 is available in sizes 50, 52, 54, 56, 58 (tested), 60 and 62cm. The sample tested sits on the scales at 8.6kg (without pedals and bottle cages). The RRP is AUD$4,999. Sharing the same frame, there's also the Domane SL 7 (AU$5,699), Domane SL 6 disc (AU$5,699), Domane SL 6 Pro ($5,499) and Domane SL 6 (AU$4,499).

Check out our overview of the full 2017 road range from Trek

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