2023 Trek Domane SLR review: A tauter ride, but some curious loose threads
Trek’s latest iteration of its Domane all-roader packs more performance than ever, but there are also some big missteps that give me pause.
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[ct_story_highlights]What it is:The fourth generation of Trek’s groundbreaking endurance road bike.||Frame features:800-series OCLV carbon fiber construction, IsoSpeed rear pseudo-suspension, down tube storage compartment, built-in chain watcher, T47 threaded bottom bracket, front and rear fender mounts, three bottle mounts, top tube feed bag mount, fully concealed cable routing.||Weight: 1,193 g (claimed, 56 cm frame only); 427 g (claimed, fork only); 7.54 kg (16.62 lb) as tested, 52 cm size, without pedals.||Price:US$13,200 / AU$18,500 / £13,400 / €14,500.||Highs:Superb rear-end ride quality, stiff and efficient-feeling under power, excellent handling, sleek aesthetics, competitively weight.||Lows:Ride quality still a little imbalanced, creaky IsoSpeed/seatpost area, exposed headset bearing, internal housing rub, disappointing tires.[/ct_story_highlights]
The Trek Domane has been one of the best-selling endurance road bikes since it first arrived on the scene way back in 2012, largely owing to its innovative IsoSpeed rear pseudo-suspension system. IsoSpeed lives on in the bike’s fourth generation, and it’s not only more cleverly package than ever, but it’s housed in what is clearly the most performance-packed iteration to date.
The last few months have proven the latest Domane SLR to be a formidable competitor in the hotly contested all-road market. But part of me wonders if some of the earlier versions’ approachability has been lost in the never-ending quest for more speed, and there are a couple of disconcerting missteps that proved annoying during testing, and somewhat concerning for the long haul, too.
A primer on the latest Domane
IsoSpeed has defined the Domane since its inception, and the brilliance and elegance of its design still has no equal in the industry.
Most bikes offer rear-end comfort with a combination of seatpost and seat tube flex; that phenomenon has been well understood for quite some time. But by adding a physical pivot at the seat cluster, IsoSpeed allows the seatpost and seat tube to bend far more under bump loads than with a more typically rigid connection. Later iterations of IsoSpeed would introduce a level of adjustability to the system so that riders could more carefully fine-tune the ride quality to their preferences (and weight), and Trek would eventually introduce a front-end analog to help balance out the comfort level between the two ends.
Whereas the previous Domane’s rear IsoSpeed system had an adjustable spring rate that allowed riders to tweak the flex characteristics to their liking, this latest version has a fixed tune that Trek says is roughly the same as the old version’s softest setting (since that’s apparently where most people ran it, anyway). The change yields a more neatly visually integrated and appealing arrangement since all of the flexy bits are now entirely tucked away inside the top tube.
In addition, there are big changes with the seatpost – or rather that it has one at all. Up until now, all higher-end Domanes used Trek’s so-called no-cut seatmast design, with a carbon fiber cap or seatpost stub that clamped to an extended seat tube stub. According to Trek, that was only way to get as much flex from the system as its designers wanted. However, this latest L-shaped IsoSpeed architecture allows for all of the desired flex while using a more conventional (and far more convenient) telescoping seatpost.
But what happened to Front IsoSpeed, you’re wondering? Based on steerer tube flex, that system was never as effective as the corresponding rear design, and with the move from standard 28 mm-wide tires to 32 mm-wide ones, the added air volume supposedly cancels out Front IsoSpeed’s nominal comfort gains so Trek says there wasn’t any point in using it anymore.
As you might expect, those structural simplifications result in some healthy weight savings, which is more than welcome since the third-gen Domane wasn’t exactly light. According to Trek, the fourth-generation Domane frameset sheds about 300 g (0.66 lb). Claimed weight for a painted 56 cm frame is 1,193 g, and the matching fork adds another 427 g – still not exactly feathery, but not bad at all, particularly when you consider all of that IsoSpeed hardware hidden inside.
Nevertheless, that figure becomes a little more palatable when you consider everything else that comes along with it.
As before, the Domane sports nominally aero tube shaping, although it’s more pronounced now with more aggressively flat-backed profiles that presumably cut through the air with greater efficiency. Trek has also retained the convenient storage hatch in the down tube located under the bottle cage mount, with plenty of room for snacks and repair essentials, and even perhaps a layer or two depending on how carefully you pack.
The previous generation’s semi-concealed cable routing has been more refined this time around with a fully hidden setup that enters the frame through the upper headset bearing and tucks in against the steerer tube, instead of the separate port behind the stem and more exposed cabling used on the old Domane. Headset bearing replacements will still be a pain (more on this in a bit), but thankfully, those control lines are at least run along the underside of the bar and stem – not through them – so swapping either of those components will be a mostly trivial process measured in minutes instead of hours.
Tire clearance is officially unchanged, although that’s not a big deal considering it was already very good. Trek says just about any 700c tire with a 38 mm hot stamp on it will fit, and prior experience has not only demonstrated those claims to hold true, but that they’re often pretty conservative. Thoroughly hidden front and rear fender mounts are integrated into the frame and fork, and even with those installed, you can supposedly still fit 700×35 mm tires underneath without any trouble.
Geometry-wise, it’s an interesting mix of road racer agility and endurance bike stability.
Up front, the steering is almost as quick as the Madone – quicker in some sizes, in fact – although that’s tempered somewhat by the more stretched-out rear end and longer wheelbase. And in a clear nod to stability, the bottom bracket drop is a ground-scraping 75-80 mm as compared to the Madone’s 68-72 mm figure. As expected, the rider position is more relaxed than what Trek uses on its road racing bikes, with more upright stack and shorter reach dimensions across the board. Neither is remotely extreme, though, so most riders shouldn’t have much issue achieving a reasonably aggressive position should they want one.
Trek sent to me a flagship Domane SLR 9 eTap model to test, built with the company’s fanciest 800-series OCLV carbon fiber blend, a SRAM Red eTap AXS wireless electronic groupset, and speedy Bontrager Aeolus RSL 37 aero carbon clinchers wrapped with 32 mm-wide Bontrager R3 Hard-Case Lite tires. Completing the spec sheet are a carbon-railed Bontrager Verse Short Pro saddle and a Bontrager Pro IsoCore carbon fiber handlebar.
Actual weight for my 52 cm sample is 7.54 kg (16.62 lb) without pedals or accessories, and retail price is a heady US$13,200 / AU$18,500 / £13,400 / €14,500.
I think I’ve ridden every generation of Domane at this point, and have always been struck by its unusually smooth ride quality (at least out back). Simply put, IsoSpeed works just as it’s claimed to, and the extent of its effectiveness is something that can only be fully appreciated in person.
That still carries through to this fourth-generation model, although the overall feel isn’t the same as in years past.
The rear end is still astonishingly comfortable, and far more so than you’d expect given the chunky-looking chain- and seatstays. Smaller-amplitude stuff is wiped out almost completely, and even nastier square-edged impacts are impressively neutralized. Basically, the way you ride IsoSpeed is to stay seated on just about everything and let the bike do the work for you. There’s also an admirable lack of bounciness while pedaling, and yet despite the obvious flex in the system, I was surprised by the amount of (good) textural feedback coming up through the rear end. Mind you, it’s nowhere near as as talkative as many other bikes out there, but it’s an acceptable tradeoff for the cushiness.
Despite losing the Front IsoSpeed system, this new Domane also strikes me as more balanced than before. The rear end is still more comfortable than the front – as has been the case with every Domane since its inception – but it’s not as stark a contrast as it used to be most of the time. I can’t say if this is due to the larger stock tires (which I ran at just 52/54 psi front/rear for my 73 kg build) or the semi-flexy Bontrager IsoCore carbon handlebar, but either way, ditching the weight and complication of the Front IsoSpeed system is a welcome update.
I say “most of the time”, though, because while the Domane does feel more balanced to me on tarmac, the huge down tube, top tube, and head tube proportions make for an absolutely punishing experience if you hit anything remotely substantial. Whereas that rear IsoSpeed setup can just flex more when needed, there’s no such relief up front, and huge jolts come up through your hands if you’re not paying attention and slam into something at speed.
Overall, the impression I get is this latest-generation Domane has a sportier personality to it and it no longer seems content to just be a comfy endurance road bike. Instead, it’s looking to provide a lot of comfort to riders who want to be out all day, but who also aren’t willing to completely give up a more performance-minded feel.
Whether that’s a good thing will depend on your perspective, but it’s something to keep in mind regardless.
Sticking to that whole performance front, the new Domane is indeed very eager under power. As you’d expect given the proportions of the thing, it’s very stiff and efficient-feeling when you step on the gas, with nary a hint of flex down below. It’s a similar story up front with that huge head tube area confidently resisting any undue twisting when you rise out of the saddle for a sprint or steep uphill pitch.
The Domane’s diet plan has paid dividends, too. Granted, 7.54 kg is still a touch on the heavy side for a top-tier carbon fiber road bike with a SRAM Red eTap AXS groupset and shallow carbon fiber clinchers, but it’s a sizable improvement nonetheless and more than fair given everything Trek has packed in here. That rear end genuinely does ride better than just about anything else out there, and while the down tube storage hatch undoubtedly adds a few grams, I’d argue it’s more than offset by the convenience factor.
Put another way, I never finished a test ride complaining about the bike’s weight.
Nor did I have any complaints whatsoever about the Domane’s handling. The quick steering geometry may seem odd for a bike in this category, but it does work. The Domane feels agile and nimble, and eagerly turns into corner when asked. After that initial response, though, that more stretched-out rear end and the longer wheelbase work together to slow things down so you never feel like you’re diving too hard toward the apex; just initiate the turn and let the tires take a set, then carve your way through. It’s wonderfully intuitive.
A bike and a half
The official tire clearance figures naturally raise the question of if the Domane can also serve as a light-duty gravel bike. In short: absolutely. In fact, that’s how I ended up spending much of my time on this thing.
As is typical for Trek, those clearance figures are rather conservative, and a set of 40 mm-wide Schwalbe G-One Allrounds (39 mm actual width on these Bontrager rims) went on with no issues whatsoever. Although some people might not be fully comfortable with how close things start to get to the SRAM front derailleur battery, there’s room to spare everywhere else. Assuming conditions aren’t too muddy, I suspect most people wouldn’t have any problems.
Either way, the Domane proved to be right at home on dirt roads and smoother gravel stretches. That somewhat firm ride on the road tires smoothes out with the increased air volume of the gravel ones, and the longer wheelbase lends an air of confidence when you start sliding around a bit. The more road-like frame geometry also makes for a bit of a rally car feel in terms of handling on loose surfaces, and while some might interpret that as scary, more skilled riders will likely just find it to be a lot of fun.
A Domane wouldn’t be my first choice if you’re primarily looking for a gravel bike, but if you’re after more of a mixed-terrain rig or your “gravel” is more like a network of decently maintained dirt roads, I’d certainly consider it.
As much as Trek nailed a lot of the fundamentals here, I was surprised by how many issues I encountered with my test sample.
For one, that IsoSpeed system may be super cushy, but mine also creaked incessantly. In fact, it was so loud on bigger bumps that it almost seemed like the frame was coming apart. Going along with that was persistent seatpost slipping, which I was only able to (mostly) remedy with a generous helping of friction paste and by slightly over-torquing the binder wedge. Trek says this is a known issue with bikes from early production runs and simple to fix.
“This is a known issue as we discovered supply wasn’t making it to spec. We have since made changes to compensate for the manufacturing variations. If this happens to a customer, we direct them to a local Trek dealer who can easily/quickly swap out the new, correct part for free and get them back riding on the road without the issue.”
Regular CyclingTips readers will already know I’m no fan of fully internal cable routing, although the setup Trek uses here is worthy of some light praise. The lines don’t actually go through the bar or stem, so both are blissfully easy to swap if necessary. And as compared to the layout of the previous-generation Domane, this one looks way cleaner.
That said, headset bearing replacement is still a concern with any routing setup where the lines pass through the upper bearing. Of course, that’s only a problem when it comes time to replace the bearing. But unfortunately, that’ll likely be a more frequent job given that this upper bearing is almost completely exposed to the elements (and the lower one isn’t much better). As is the case with any bike that has a similar layout, replacing headset bearings often requires new brake hoses (or at least fittings), new bar tape, and a lot of labor, so if you regularly ride in the wet and are considering a Domane, I’d advise either setting aside a sizable chunk of money for regular bike shop visits or getting really good at doing the work yourself.
“The logic behind the design is that we’ve noticed we infrequently see our customers change their headsets,” a representative from Trek replied when I asked about this. “We’ve also seen very few related issues. For example, for all our road bikes dating back to 2013 with similar integration as Domane, we’ve received approximately ten warranty issues related to this.”
That may very well be, but just because customers don’t change their headset bearings doesn’t mean they shouldn’t be changed, and just because something isn’t submitted for a warranty claim doesn’t mean there isn’t a maintenance issue inherent to the design. Would it really be that hard to add a couple of lip seals here?
I may not win the war on hidden cable routing (sadly, that ship has sailed), but I’m still going to scream from the rooftops that brands should at least pair those rats’ nests with either more durable headset bearings or better seals. In this case, there’s neither.
Speaking of internal routing, I also noticed the rear brake hose rubbing inside the frame when turning the bars at not-overly-extreme angles. Will this be an issue over time? That’s hard to say, but most experienced shop mechanics will probably have tales to share of brake and derailleur lines slowly sawing through poorly protected areas of various mountain bike carbon fiber frames over the years. I can’t say for sure that this will happen here – and this certainly isn’t an issue limited to Trek – but it’s something I worry about regardless, particularly given it’s potentially inside the frame where no one will be regularly looking for it.
This particular test bike was also a convenient reminder that threaded bottom brackets can still creak, as mine occasionally did under particularly hard pedaling. That said, threaded systems are at least easy to fix (a layer of plumber’s tape and some grease does wonders) – and I would have, had one of the dozen cup tools in my tool cabinet actually fit.
For the most part, there aren’t too many surprises here.
The SRAM Red eTap AXS stuff is great, and Trek has wisely gone with the versatile 2x configuration with 46/33T chainrings and a 10-33T cassette that provides a mountain-taming 1:1 climbing ratio.
The Bontrager wheels are excellent: light and snappy, modestly aero, super stable in crosswinds, incredibly easy to set up tubeless, reliable DT Swiss hub internals. You get the point.
I can’t say I was a fan of the Bontrager R3 Hard-Case Lite tires wrapped around them, though. They’re decently grippy, and prior experience has demonstrated them to be impressively long-lasting. But they’re also tangibly slow (confirmed by our friends at Bicycle Rolling Resistance) with a thick and stiff casing that makes for a less-than-inspiring ride quality. The bike deserves better.
It was a similarly mixed bag on the finishing kit.
That Bontrager Verse Short Pro saddle? Awesome. Tons of support for all-day riding and an excellent shape that minimized soft-tissue pressure and chafing. I’d almost put this head-to-head with a Specialized Power, in fact. It’s good stuff.
But that handlebar… pass (at least for me). I generally love traditional-bend bars, but this one just never felt right in my hands. The 75 mm reach dimension should be fine but it feels short in reality, and the drops feel oddly deep with a curvature that doesn’t mesh well with my large-sized palms. And the corresponding tape was pleasantly grippy, but almost too grippy if you don’t like to wear gloves, and could’ve used more padding.
Overall, I think Trek did a great job on the core attributes of this fourth-generation Domane. It’s back to a more reasonable weight after a couple of generations of overindulgence, it’s very unusually comfortable, the handling is superb, and it’s no stranger to going fast. The convenience of those double fender mounts and the extra bottle and bag mounts – not to mention the down tube storage – are big plusses, too.
In short, it’s a lovely bike to ride all day, and on a wide range of road surfaces.
Bikes are more than just short-term thrills, though, and the creaking and slipping in the seatpost area, the exposed headset bearing, and that internal brake hose rub just make me wonder about what issues might persist long-term. I’ve heard from Trek dealers that a retrofittable part revision has since corrected the seatpost problem, but those other two concerns still give me pause. If Trek can address those as well, I’d happily declare this Domane a winner. But until then, I’d carefully wear the pros and cons before plunking down your wallet on this one.
More information can be found at www.trekbikes.com.