2021 Trek Emonda review: the semi-aero, ‘faster everywhere’ climbing bike

by James Huang


First introduced in 2014, the Emonda has always been Trek’s premier climbing bike, with a keen focus on low weight and high stiffness. However, we now have a much better understanding of the role aerodynamics play when it comes to going fast — even when climbing — and, as expected, the brand-new Emonda SLR and Emonda SL bikes have undergone an aero makeover. The Emonda is still light, and it’s still stiff, but now there’s an extra dose of free speed included, too.


Story Highlights

  • What it is: The latest iteration of Trek’s premier climbing-specific road bike.
  • Frame features: Mild aero tube shaping, OCLV 800 carbon fiber construction, internal cable routing, T47 threaded bottom bracket.
  • Weight: 698 g (claimed, unpainted 56 cm frame only); 365 g (claimed, unpainted fork only); 6.81 kg (15.01lb), complete 52 cm Emonda SLR 9 eTap model as tested, without pedals.
  • Price (as tested): US$12,000 / AU$15,800 / £9,700 / €11,000
  • Highs: Low frame weight, excellent chassis stiffness, superb handling, intelligently designed internal routing system, traditional shape, no more BB90.
  • Lows: Somewhat chattery ride quality, no rim-brake option, long-term headset hassles.

The three-legged stool of performance

It has long been the prevailing mainstream sentiment that aerodynamic efficiency is only important when you’re moving fast — and given the non-linear way aerodynamic drag holds a rider back with increasing speed, there’s some truth to that. However, even moderately fit riders are still often going fast enough on most climbs that aerodynamic efficiency can play a measurable role, and given the “free speed” that the existing Emonda left on the table, Trek saw fit to make use of that potential with the latest redesign.

As Giant recently did with its TCR range of light-and-stiff road racing bikes, and Scott before them with the latest Addict RC, the new 2021 Emonda now sports truncated-airfoil tube profiles on the down tube, head tube, seat tube, seatstays, and fork blades. The no-cut integrated seatmast remains round, as does the telescoping seatmast head.

It’s one thing to just make a frame more aerodynamic. Making it more aerodynamic while also keeping it light and stiff is the tricky part. Photo: Trek Bicycle Corporation.

Upper-end Emonda SLR models also get a new Bontrager Aeolus RSL integrated carbon fiber stem and handlebar, the latter with notably flattened tops. Unlike the integrated setup on the full-aero Madone SLR, this is a true one-piece design with no angle adjustment so as to save weight.

Just like that Madone cockpit, though, the previous Emonda’s once-exposed cabling up front has been replaced with a fully hidden setup in the interest of more cleanly slicing through the air, with derailleur and brake lines now entering the frame at the head tube, immediately in front of the stem. Several new Emonda models will come with revamped Bontrager Aeolus aero carbon clincher wheels, too (and you can read about those in more detail here).

The truncated airfoil tube profiles are somewhat subtle, but apparently effective.

So, just how aero is this thing?

According to Trek, if you were to take two identical riders, each putting out 350 watts, and put one on an old Emonda and the other on the new one, the one on the new Emonda would have a minute lead after an hour — on flat ground, that is. But the Emonda is supposed to be a climbing bike, no? Well, if you took those same two riders and sent them up L’Alpe d’Huez (a 13.85 km-long climb with an average gradient of 8.1% and maximum gradient of 13%), the rider on the new Emonda would finish 15 seconds ahead. On the Stelvio? Twenty-one seconds. And on something as long as the Taiwan KOM Challenge, Trek says the rider on the new Emonda would have 80 seconds to kick their heels up before the other rider showed up.

“We expect the vast majority of riders are going to choose Emonda,” said Trek’s director of road and Project One, Jordan Roessingh. “Madone is still significantly faster, but you’ll see a lot of Emondas under riders.”

Despite the newfound semi-aero shaping, the Emonda retains a traditional double-diamond frame layout.

Trek says the engineers behind the shape of the new Emonda obviously had to tread a very fine line between making the new bike more aerodynamic and sacrificing the traits that make the bike what it is, supposedly going through hundreds of CFD (computational fluid dynamics) and CAD (computer-aided design) models of various individual tube and frame shapes before arriving on the final form.

In the end, the new Emonda SLR is still primarily a light-and-stiff machine in the classic sense, and claimed weight for an unpainted 56 cm frame is just 698 grams, with the matching fork adding 365 g (the Emonda SL is 1,142 g and 380 g). In either case, paint adds another 25-100 g, depending on design. Overall, the figures are hardly heavy, but still slightly heavier than the previous model nonetheless. Likewise, stiffness figures have fallen off a bit as well, although supposedly not enough to make any difference.

“The key stiffness numbers – Trek Full Frame, Tour BB, and Vertical Compliance — are all within 5% of the old frame,” Roessingh said.

The chainstays are fairly big and bulbous.

Potential buyers shouldn’t expect any improvement in ride quality, either, which is perhaps a touch surprising given how much Trek has emphasized rider comfort on other performance-minded platforms — including the Madone.

“The [ride quality] goal was to match the vertical compliance of the old bike,” said Trek road product manager Anders Ahlberg. “We were really close, within 7%, so most people shouldn’t notice a difference.”

One nice surprise is an apparent boost in frame durability. For the Emonda redesign, Trek developed a new carbon blend for the higher-end SLR models, dubbed OCLV 800. As expected, it’s lighter than the OCLV 700 mix that was used last year, with Roessingh saying the new frame shape would have been about 60 g heavier otherwise given the increase in surface area. However, OCLV 800 is also said to be 30% stronger than OCLV 700 and absorbs more energy, thus offsetting the brittleness that usually accompanies increases in fiber modulus.

Fewer geometry options, no more rim brakes

Trek has resisted temptations to follow other industry trends like dropping the seatstays (doing so apparently would have added 50 g of weight), and the Emonda retains its semi-classic double-diamond configuration with just a modest slope to the top tube. Although it’s a very different machine than the one it replaced, it still sports a traditional aesthetic, which plenty of potential buyers will appreciate.

More controversial will be Trek’s decision to only offer the new Emonda with disc brakes; there is no rim-brake option, even for Trek-Segafredo team riders. According to Trek, its mainstream customers haven’t expressed any interest in “investing in old technologies”, and with an increasing number of pro teams and riders already making the switch, there was seemingly less motivation than ever to develop parallel models.

12 mm thru-axles and flat-mount disc brakes are used front and rear.

That said, it’s worth mentioning that the vast majority of Emonda buyers will never see a race (and, thus, will never be subject to UCI minimum weight rules), so the loss of a true ultralight climbing bike from a major brand is kind of a bummer. It wasn’t long ago, after all, that Trek offered the ultra-premium rim-brake Emonda SLR 10, with a claimed weight of just 4.6 kg (10.25 lb). Weight-weenies looking to save every possible gram will, of course, be able to build for themselves a custom bike that’s lighter than the stock Emonda SLR 9 flagship model, but being locked into disc brakes will obviously limit potential on the scale.

Somewhat expectedly, Trek has also decided to merge the existing H2 and H1 frame geometries into a middle-of-the-road H1.5 variant across the entire Emonda family, just as it did with the Madone a couple of years ago. As the name suggests, H1.5 is not as long or low as the H1 variant (which was only offered with Project One custom builds and bare framesets), but it’s more aggressive than the H2 geometry that graced every complete stock Emonda previously.

“None of our pro riders needed anything lower than [H1.5],” said Roessingh. “If they can get aggressive enough, the vast majority of consumers should also be able to achieve their fit.”

Trek has also done away with women-specific models for the Emonda range entirely, which is an especially intriguing move given how much time, energy, and money Trek has invested in its Women Specific Design project in years past.

Just as Specialized (and others) have changed tack in recent years on the same subject, Trek’s position now is that the Emonda’s H1.5 geometry is sufficiently accommodating so as to work for nearly everyone, regardless of sex or gender. To Trek’s credit, each Emonda is offered in a generous eight-size range — from 47 cm up to 62 cm — and there are a decent number of stock color options, too. Perhaps more to Trek’s point, the revised geometry supposedly hasn’t been an issue for the Trek-Segafredo women’s road team, either.

Smaller sizes nevertheless get some slightly adjusted spec, and Trek says it has programs in place with its dealer network that allow customers to swap various fit-related components (such as saddles) at little-to-no cost.

The actual head tube is quite short, however the effective length is pretty normal thanks to the large cover used up top to help guide the cables into the frame.

Here’s to the mechanics

There are several other updates on the new Emonda, a few of which will warm the hearts of home and professional mechanics alike.

First and foremost, Trek is continuing to transition away from its problematic BB90 press-fit bottom bracket design, opting to equip the Emonda with the same slightly modified T47 threaded shell that already graces the Domane endurance road bike and Crockett cyclocross bike. This should not only reduce the incidence of creaking, but will also make regular maintenance much less of a headache. The move to T47 will also finally allow the use of oversized spindles in a high-end Trek road bike, whereas BB90 would only work with 24 mm-diameter setups like Shimano Hollowtech and SRAM GXP.

There’s a lot of surface area to be found here, as well as a T47 threaded bottom bracket instead of Trek’s longstanding (and occasionally problematic) BB90 press-fit design.

According to Trek, the move to T47 did increase the frame weight by about 30 g relative to what it would have been with BB90 given the metal sleeve required. However, the convenience factor more than outweighed that nominal gain — pun intended — and when you consider that most cranksets with oversized spindles are actually lighter than their non-oversized counterparts, the total system often actually ends up lighter, anyway.

Trek’s interpretation of T47 is admittedly a millimetre narrower than the wide-format T47 system that was already on the books so as to provide better tool purchase, but it nevertheless doesn’t present any real compatibility headaches since existing T47 bottom brackets will still work just fine here.

It’s also worth mentioning that while the Emonda has moved to a fully concealed cable system, the way Trek has accomplished this is far easier to live with than most. Instead of routing the lines internally through the handlebar and stem, the Bontrager Aeolus RSL cockpit on the Emonda SLR tucks the brake hoses and derailleur housings (or wires) into channels molded on the underside of the bar and stem. Bar tape holds everything in place further out on the tops, while a single profiled clamp secures the whole lot underneath the stem. Combined with the conveniently split headset spacers, there’s no need at all to disconnect the brake or derailleur lines if you need to swap a stem length or bar width, therefore keeping a 15-minute job from turning into one that potentially takes a few hours.

Those lines do still run down through the middle of the upper headset bearing, however, and the front brake hose also takes a detour into the inside of the steerer tube just above the lower headset bearing. As a result, swapping either headset bearing will be anything but a quick job. The front brake hose also needs to be cut quite precisely for a proper fit as there isn’t a whole lot of wiggle room inside the front end for excess length.

“[There’s] not as much as we would like — maybe about 2 cm?” admitted Ahlberg. “That’s the one downside to the serviceability of an externally grooved system.”

Although the cabling is hidden, it’s not run through the handlebar and stem. Instead, the cables are clamped to the underside, which makes swapping bars and stems a lot easier.

Models and availability

Trek will offer five models each of the Emonda SLR and Emonda SL (specifics vary based on region). The former will feature the top-end OCLV 800 carbon fiber blend and Bontrager Aeolus RSL integrated cockpit, while the latter will use the same frame shape — but a lesser OCLV 500 carbon fiber mix — and a more conventional handlebar and stem combo. According to Trek, the weight difference between Emonda SLR and Emonda SL models with comparable build kits is about half a kilogram or so (1 lb).

Not pictured are the following models:

– Emonda SL 6 Pro, built with a Shimano Ultegra mechanical groupset and Bontrager Aeolus Elite 35 wheels; 8.06 kg / 17.78 lb; US$3,800 / AU$5,500 / £3,350 / €3,880-4,000

– Emonda SLR 6, built with a Shimano Ultegra mechanical groupset and Bontrager Aeolus Pro 37 wheels; 7.26 kg / 16.0 lb; US$6,700 / AU$9,300 / £5,450 / €6,200

– Emonda SLR 7 eTap, built with SRAM Force eTap AXS and Bontrager Aeolus Pro 37 wheels; 7.35 kg / 16.2 lb; US$8,800 / AU$11,850 / £6,850 / €7,800

– Emonda SLR 9, built with Shimano Dura-Ace Di2 and Bontrager Aeolus RSL 37 wheels; 6.78 kg / 14.95 lb; US$12,000 / AU$15,800 / £9,700 / €11,000

Trek will also make the Emonda SLR (but not the Emonda SL) available for purchase through its Project One program, which will allow buyers to customize the build kit and paint to better suit their taste (and budget). Going along with the addition of the Emonda SLR model to the Project One ecosystem are several new Icon-level paint jobs, as well as new KOM variants with more minimal finishes to save precious grams. Both of these come at a more premium price than the more standard finish options, but they’re also quite stunning to behold.

The Emonda SL and Emonda SLR will also be offered as bare framesets, with pricing and availability to be confirmed.

Forget about all the tech talk — what’s it like to ride?

Trek may only just be officially launching the new Emonda range today, but the company was actually able to provide me with an early sample of the top-end Emonda SLR 9 eTap model several weeks ago — which I’ve been riding since then. Actual weight for my 52 cm sample without pedals or accessories was a feathery 6.81 kg (15.01 lb), complete with a SRAM Red eTap AXS wireless electronic groupset, Bontrager’s new Aeolus RSL 37 lightweight carbon clincher wheels, the new Bontrager Aeolus RSL one-piece carbon fiber handlebar-and-stem, a carbon-railed Bontrager Aeolus Pro saddle, and 25 mm-wide Bontrager R4 320 tires.

The new Trek Emonda isn’t any lighter or stiffer than the old one, but it’s supposedly quite a bit more aerodynamic – a neat trick considering it still looks very normal.

Just as you’d expect, the bike is a superb climbing companion. The low weight is certainly noticeable, as is the impressive chassis rigidity. It’s more of a hot-air balloon on the climbs rather than an anchor — especially on steeper pitches — and there’s a tangible sense of efficiency when you push on the pedals. Gaining altitude just feels easier relative to something heavier and/or less rigid than what Trek has produced here.

I know, I know. A light and stiff bike is good for climbing? Big surprise. And while the Emonda SLR 9 eTap is light, it’s not exceptionally so, so a more exotic setup would obviously feel even better in this respect.

What goes up must come down, of course, and what was far more impressive to me is how the Emonda SLR 9 eTap behaves at high speeds. Some lightweight bikes I’ve ridden — especially ones with lightweight wheels — can feel nervous or jittery when charging down descents, but that’s certainly not the case here. In fact, I found the bike to feel just as calm and composed at 80 km/h (50 mph) as it does at 18 km/h (11 mph). With a 58 mm trail figure, the front end is still appropriately quick and darty, and just as I’ve enjoyed on the Madone, the Emonda is a joy to snake down twisty canyon downhills. However, there’s also a reassuring sense of stability and solidity when all you want to do is hold your line.

Nope, no IsoSpeed to be found here. Too heavy, at least for this bike.

The ride quality is a little on the chattery side, but that’s to be expected, not only given the genre, but also the bike’s emphasis on structural efficiency. It’s not unusually rough, however I still found myself wishing for a bit more tire clearance here. The stock 25 mm tires work well on well-maintained asphalt, but riders regularly finding themselves on rough tarmac (or even dirt) would be advised to max out the Emonda’s tire clearance.

Speaking of which, Trek’s track record of being conservative in terms of what will fit and what won’t seems to be holding up here. Although Trek officially only approves the Emonda for 28 mm-wide treads, there’s still more than 42 mm of space in between the pinch point at the chainstays. As for what will actually squeeze in between there … well, that’ll depend on how much leeway you want to leave for yourself.

But is the bike really more aerodynamic than the old Emonda? Unfortunately, I can’t really say since I didn’t have an identical previous-generation model to compare against. However, if you take Trek’s claims at face value, what I like is that they’ve managed to infuse a fair bit of aerodynamic efficiency into the equation without taking away what people really like about the Emonda family — including the traditional appearance, which is much easier said than done.

As a result, the aero bit will be more of a nice bonus to most buyers with no significant downsides that I can see, and I mean that in quite the literal sense as this is a really good-looking machine with refreshingly traditional lines and proportions. I personally could do without the giant Trek logo on this particular paint job, but so be it. Thankfully, Trek’s Project One program gives you more than a few options for choosing something more subtle, and according to Trek’s figures, a shocking percentage of high-end customers go the custom route.

This translucent paint job is oh-so-pretty in bright sunlight.

Kudos to Trek, too, for investing some time and energy into making the new bike easier to live with over the long haul.

I didn’t experience any bottom bracket creaking issues on my test sample, but then again, it’s only been a few weeks, and the bike hasn’t seen any water, either. However, if it does occur — let me remind you that even threaded bottom brackets are prone to creaking — it’s a far more straightforward process to take the assembly apart for a quick cleaning, greasing, and reinstallation. There are also heaps more aftermarket options available here as compared to what you could do with the old BB90 setup. Good riddance, I say. Trek can’t introduce T47 on to the rest of the road range soon enough.

As someone who regularly takes things apart for a living, the channeled external routing setup on the integrated handlebar-and-stem combo is not only a huge sigh of relief, but a solution that’s so obvious in hindsight that it’s a wonder why more brands don’t do something similar (for the record, Canyon has long used this approach for its integrated cockpits). Yes, it’s visually perhaps not quite as clean as fully internal setups, and yes, you can feel the housing a bit when you wrap your fingers around the bar tops (which, on my sample, were only partially wrapped, although I’d personally opt to wrap the bars the usual way for a surer grip and improved comfort). However, both of those compromises are exceedingly minor relative to the massive headache that internally routed handlebars can often bring on.

The molded guide tube saves a bit of hassle and frustration if you need to feed a line through the fork.

Conversely, though, the fact that the control lines are routed through the headset bearings will eventually be a pretty big pain in the rear end for riders that regularly head out in the wet. At minimum, replacing the lower bearing will require you to disconnect the front brake hose (in addition to removing the fork as usual). If you need to replace the upper bearing, you’ll also need to undo all of the cables completely. In either case, there’s a decent chance you’ll need to rebleed the brake(s) after you’ve got everything back together, too.

It doesn’t exactly help, either, that there’s no supplemental rubber seal between the fork crown and lower head tube, meaning the lower bearing is perilously exposed — a scenario that’s become very common since bike brands started molding crown races directly into the fork crown.

Such is the cost of progress, I suppose.

The reach of the Bontrager Aeolus RSL handlebar is quite long at 93 mm, when provides lots of room to stretch out.

That said, I’m a big fan of the somewhat unusual dimensions of this integrated setup even with the non-adjustable tilt. Most companies these days have committed to a compact bend, which is nice in the sense that it makes the drops more accessible for more riders, but somewhat silly in the sense that your posture actually changes very little when you move your hands back and forth between the various hand positions.

The drop dimension on the Bontrager Aeolus RSL is pretty average at 123 mm, but the reach is quite long at 93 mm (80 mm or so is far more typical), and Bontrager’s trademark Variable Radius bend lets you utilize every bit of that length instead of forcing your hands further rearward. As a result, there’s ample room to really stretch out your back when you need or want to, and there’s far more real-world position variation than what you usually find on most modern setups. How much do I like it? I’m actually considering using one of these on my personal Seven road bike.

Overall, Trek has done a solid job here of updating the Emonda, infusing meaningful improvements in several key areas, but without breaking the basic formula that has made the bike so popular. I could obviously do without the long-term headaches associated with the headset bearing situation, but aside from that, there’s not much to complain about here, and an awful lot to like.

Just don’t be shy with the grease down there, eh?

www.trekbikes.com

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