Trek has touted the Emonda as its climbing bike since introducing it in 2014. But the 2021 revision threw aerodynamics into the light-is-right alchemy, producing a road race bike that blurs category lines.
Editor’s note: Trek issued a recall on this bike and is replacing the integrated stem and handlebar free of charge to the customer. Learn more in our full article.
The claimed aerodynamic gains over the prior model are huge. Trek states that the current Emonda is 60 seconds faster per hour at 350 watts of output on the flats. The claimed gain on an 8% grade is 18 seconds.
And the bike is still substantially lighter than Trek’s aero road race bike, the Madone. The current equivalent Madone has a claimed weight of over 1.3 pounds heavier than the Emonda SLR 9 eTap.
I used the Trek Emonda SLR 9 eTap as a long-term review bike, putting it on the roads for 18 months. The bike rolled across super smooth, new tarmac and neglected country blacktop. I tested other parts on the bike and took it on several trips to ride terrain different from my home in the Hill Country of Central Texas. It has been in my testing rotation longer than any bike.
In short: The Trek Emonda SLR 9 eTap is a pure race bike at the highest end. Although it may be called a climbing bike, the new aerodynamics vault it into a well-rounded road racing machine of the highest caliber. And it still satisfies the weight weenies.
How Aero Is the Emonda?
Aerodynamics on a bicycle frame is mainly dependent on tubing shapes. And often, going “full aero” means losing vertical compliance, which hinders comfort. Super aero tubing also often adds weight.
Trek had to walk fine lines to keep the weight and compliance advantages and maintain lateral and torsional stiffness. But engineers wanted substantial free speed offered by improved aerodynamics.
Modern bike designers use CFD (computational fluid dynamics) and CAD (computer-aided design) to help them in their quest for the ultimate alchemy of shapes to produce the intended results. And Trek claims they scrutinized every inch over hundreds of CFD and CAD models.
The result is truncated-airfoil profiles other than the seat tube, which is still round. Trek also went integrated, with a one-piece bar and stem that hides the cables from the wind.
The claimed reduction in drag is 182 g, with the claimed frame weight for an unpainted 56 cm size being 698 g.
Somewhat surprisingly, Trek kept the non-dropped seat stays. This greatly pleased my antiquated tastes in bicycle aesthetics.
Other Significant Frame Changes
Trek didn’t stop at the truncated airfoil. The brand incorporated several other significant changes.
H1.5 Fit
Trek used to offer aggressive (H1) and more upright (H2) geometries but split the difference on the new Emonda SLR with the middle-of-the-road H1.5. This singular geometry follows the lead of the full aero Madone.
Surprisingly, Trek omitted women’s-specific Emonda frames. But it does offer a full spread of sizes, from 47 cm to 62 cm.
T47 Bottom Bracket
Gone is the BB90 press-fit bottom bracket. A T47 threaded bottom bracket takes its place, pleasing home mechanics everywhere. The BB90 was reportedly problematic, although I never experienced issues with any Trek BB90 bottom brackets.
Not only does this follow the current trend to a homologated bottom bracket standard, but T47 also allows oversized crank spindles where BB90 did not.
800 Series OCLV Carbon
Trek’s longstanding OCLV (Optimum Compaction Low Void) carbon on the Emonda SLR frame moved from 700 series to 800 series, purportedly to allow aero profiles without a concomitant increase in weight.
The Waterloo, Wisconsin-based brand claims the new carbon contains fibers that are 30% stronger, with the same amount of stiffness as before, and with no gain in mass. This means less material is required to maintain the same positive characteristics, which translates to aero shapes without adding weight.
Trek also developed over 50 new carbon layups (how the carbon fibers are aligned) to create the new 800 Series OCLV. Real-world testing of the final layup choices was done by the professional Trek-Segagredo team. And the brand builds these frames in Waterloo.
Trek Emonda SLR 9 Ride Experience
Testing high-end road bicycles these days is an act of trying to split hairs that have already been split. All these bikes are sublime. Any differences in performance are minuscule, and much of it is subjective. But here’s my best attempt after 18 months of solid use.
Damn, It’s Light
There is no getting around how light the bike is (our 56 cm tester weighs a verified 14 pounds, 5 ounces with tubed tires). That attribute alone brought me joy when accelerating or climbing. The Emonda SLR 9 eTap floated like a butterfly. No need for more explanation. Remember when race bikes were 21 pounds?
The Fit
The H1.5 geometry fits me exceptionally well. I have had custom-built titanium road race frames, and if I ever ordered one again, I would replicate the Emonda SLR geometry.
I am 6 feet tall, but my inseam is only 32 inches, making my torso long. My lower back is accustomed to road racing positioning, but my hips and hamstrings are not exceptionally flexible. I found the reach and stack spot on, and the stock-integrated 100mm stem, without spacers, was also perfect.
The 42cm-wide bars of the Bontrager RSL felt correct, but I had to move the SRAM Red brake hoods a touch higher up the bar’s primary curve to feel comfortable. Moving the hoods up the bar created slack in the brake hoses that was hard to manage. The stiff hoses run straight from the underside of the bars through the head tube.
A tiny range of brake hose lengths will provide a clean run. So this is a concern to anyone that wants to change the dimensions of the front cockpit. But lines are not threaded through the bar, simplifying at least that part of the process.
Stiffness vs. Compliance
Climbing out of the saddle and sprinting revealed that the Trek Emonda SLR chassis is plenty stiff laterally and torsionally about the head tube. The bottom bracket felt equally rigid, and I never felt like the frame was squandering energy.
Riding a stiff, efficient bike typically means trading off some vertical compliance and comfort. And I felt the Emonda SLR chassis sat on the efficient side more than the comfortable side. But it wasn’t overly so, as it tends to be with super light bikes. Much of how the bike felt regarding compliance came down to wheels and tires.
The Emonda SLR 9 eTap came with tubeless-ready Bontrager Aeolus RSL 37 wheels, which felt like a great all-around road wheel. But the Bontrager R4 320 tires (with tubes) were 25c. I felt wider tires on hookless rims with lower air pressures would drastically improve the comfort. Trek states that the frame can accept 28c tires.
It was ridden with various wheels and tires over 18 months as a long-term review bike. Using hookless wheels, 28c tires, and lower pressures improved comfort drastically.
I felt like just swapping the tires to 28c on the RSL 37 stock wheels would be such a welcome change. But going to a wheel like a Zipp 404 Firecrest or Zipp 353 NSW with the ability to use lower pressures (for me, on those wheels, I ran under 72 psi) was an absolute game changer.
It gave me the best of both worlds. A light, super efficient bike that kept me comfortable over long hauls on rough chip seal blacktop.
Handling
As expected, the Trek Emonda SLR 9 eTap was a snappy, quick-turning bike. On twisty tarmac, it felt like it wanted to turn about the head tube axis, with the rest of the bike to follow — more of a “turn and flick” instead of the other way around. It was one of the quicker-steering road bikes I’ve tested over the last few years.
Yes, the bike required attention on the straights and in groups, but I never thought it was twitchy or nervous. It reacted to small inputs without delay, but that’s what I expect in a WorldTour race bike. The bike wasn’t a lazy café cruiser, and it shouldn’t be.
On wider radius turns on smooth pavement at high speeds, the Emonda was pure joy. I felt the chassis was reading my mind, putting the tire contact patches precisely where I desired, and fed me the tactile information I needed to predict how it would respond to any slight irregularities in the road.
How Fast Is the Trek Emonda SLR 9 eTap?
The bike came with a SRAM Red eTap AXS groupset with a power meter. And I’m familiar with the power output versus speed on my regular routes. I’m not a human strain gauge, but subjective feelings mated with the power output did convince me that for a “non-aero” bike on moderately aero wheels, the Emonda SLR 9 eTap was a rocket.
On calm days on smooth, flat pavement, the feeling of speed while churning a tall gear was palpable and brought a big grin to my face. Trek’s data points to an aero gain while climbing, but I felt the bike’s super light weight and stiffness contributed more to my feeling of speed on ascents.
With either the Bontrager RSL 37 wheels or the mentioned Zipp wheels, I didn’t feel any buffeting or other negatives of aero profiles except in extremely windy conditions. Only once did the buffeting cause an unstable feeling to the point where I tensed up.
I had exited the cover of trees on a speedy descent, and the sudden, super-gusty, 90-degree crosswind got me pretty good. I cannot say that about other “full aero” setups, which I’ve found somewhat puckering when large trucks pass me.
So, in the end, I felt like the aero gains of the new tube shapes delivered free speed without much downside.
Final Thoughts
One trend in cycling that I don’t necessarily like is the continued segmentation of products. The number of mountain bikes one could “need” is astounding. And coming from road racing in the ’80s, the “need” for a climbing bike and an “aero” bike seems superfluous. Now throw in gravel rigs, and you could have a garage full of bikes.
I can somewhat understand having multiple mountain bikes, as different terrains’ travel and handling requirements dictate wholly differing chassis. But road bikes? Most of us will never see the level of competition that demands different chassis and a slew of wheels. But plenty of serious recreational cyclists buy high-end road bikes, and it’s the category that splits choices into “aero” and “climbing.”
Although Trek labels the Emonda SLR 9 eTap as a “climbing” bike, with the aero gains, it makes a perfect all-around high-end road bike. It’s under the minimum legal weight for the WorldTour, satisfying the weight-obsessed.
It has enough aero shaping for legitimate free speed gains, yet it doesn’t ride like a brick (especially with wider tires and lower pressures). And it’s super efficient.
The MSRP of the Trek Emonda SLR 9 eTap is an astonishing $13,000. It sits at the top of the Emonda SLR lineup. But the pricing is in line with other bikes of the same caliber. And for that money, to me, the bike should perform well in all areas. Which it absolutely did.
Trek does offer Emonda SL bikes with the same aero gains at a much lower price, using 500 Series OCLV carbon.
