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by Matt Wikstrom
August 18, 2015
Photography by Matt Wikstrom
In developing the Émonda, Trek devoted considerable resources to designing a lightweight race bike and trumped the industry with a 690g frame. CTech editor Matt Wikstrom takes a close look at the new bike and assesses the influence of different grades of carbon fibre by comparing the mid-level Émonda SL6 with the upper-level SLR6.
Trek is well known for its Madone and Domane road bikes but neither was ever designed as a lightweight race bike. So in 2012, the company set out to see what it could achieve and came up with the Émonda. The development process required over 30 months but the result is currently the world’s lightest production road bike. At 4.65kg for a size 56cm bike, the Émonda SLR10 trumps the previous title-holder by almost 1kg, but at a significant cost: $17,999.
There are, of course, more affordable versions of the bike yet Trek believes that the Émonda range is the world’s lightest production road line. There are over a dozen models in the Émonda range including women’s-specific versions and custom builds via Trek’s Project One portal. Variations in parts specifications account for some of the differences between each model, but there are also three different versions of the frameset (designated S, SL, and SLR) that differ in carbon fibre grade, country of manufacture, and ultimately, final weight.
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Trek uses five different grades of carbon fibre for frame construction that vary in weight, strength, stiffness and cost. At one end of the spectrum there is 300 series carbon, a cost-effective blend, and at the other there is 700 series carbon, a high-cost, low-weight, military-grade blend.
As the base model in the range, the Émonda S is made in Taiwan from 300 series carbon with a simplified design (e.g. a standard seatpost is used rather than semi-integrated design) to reduce production costs.
In contrast, the Émonda SL and SLR share many of the same design features (such as a semi-integrated seatpost) however the SL is manufactured in Taiwan from 500 series carbon while the SLR is manufactured from 700 series carbon in the U.S.A. The use of the highest-grade carbon affords the SLR a weight saving of over 300g when compared to the SL but almost triples the price of the frameset.
While weight was an important design imperative for the Émonda, Trek spent a considerable period road testing the new bike to refine its handling characteristics while paying attention to its stiffness. Riders from Trek’s professional team were instrumental in determining the value of each refinement but engineers were also guided by data collected from strain gauges and accelerometers fitted to prototypes.
CT’s roving reporter Dave Everett attended the launch of the Émonda last year and was able to take one ride on the SLR8. While his report served as a good introduction to the Émonda, the new bike deserved a longer look. In this review, I spend a lot more time on the Émonda, and thanks to Trek Australia, compare two models — SL6 and SLR6 — to learn more about how different grades of carbon fibre affect the performance of the bike.
In developing the Émonda, Trek’s engineers pared away at the frame and forks until they arrived at the minimum structure that satisfied all of their performance and safety criteria. The result is a frameset that is noticeably skinnier than the Madone and Domane.
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Like the Madone and Domane, the Émonda SL and SLR framesets utilise a BB90 bottom bracket and E2 headtube. At 90mm wide, the BB90 bottom bracket provides a broad footing for the downtube and chainstays to help the stiffness of the frame. The E2 headtube also helps the stiffness of the frame with an oversized lower headset bearing and tapered fork steerer.
Trek further refines the design of the SLR with an asymmetric steerer that is wider from side-to-side and skinnier from front-to-back. The difference provides extra stiffness for cornering while affording some compliance to soak up road shock.
The Émonda SL and SLR also inherit the semi-integrated seatpost design that was introduced with the Madone. A seatpost cap fits over an extended seat tube and offers a range of 10cm for saddle height adjustment. Trek offers a choice of two lengths for the seatpost cap (135mm and 175mm) along with two offsets (5mm and 20mm) to help with refining the fit of the bike.
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Both framesets provide internal routing for the gear and rear brake cables, with interchangeable cable stops and ports to suit mechanical and electronic transmissions. There is also an adjustable chain keeper that is integrated into the seat tube while the left chainstay is ready to accept Trek’s DuoTrap S speed/cadence sensor.
Aside from the difference in carbon fibre blend and country of origin, the SLR frameset is further distinguished from the SL in a number of small ways. I’ve already mentioned the asymmetrical fork steerer above. Another difference lies with the brake caliper mounts: the SLR frameset uses direct mount calipers front and rear, while the SL uses conventional calipers.
The front derailleur mount also differs: the SL frameset has an alloy fitting that is riveted to the seat tube while the SLR has a carbon mount that is molded into the frame. Finally, the SLR frameset is offered with a choice of Trek’s H1 or F2 fit, while the SL is only available with a H2 fit. The difference between the two is in the length of the head tube, which is 30-35mm taller for the H2 fit at every frame size (see chart below).
There is a choice of up to nine frame sizes for the Émonda, as shown in the table below:
The range of frame sizes varies, depending on the model and fit of the frame. The SL6 is offered in sizes 47-62cm with a H2 fit only while the SLR6 is available in sizes 50-62cm with a H1 fit and 47-64cm with a H2 fit. Trek’s H1 fit can be considered very aggressive and race-oriented, affording plenty of handlebar drop. In contrast, the H2 fit is more moderate but riders looking for a more upright position will be better served by the geometry of Trek’s Domane. Visit Trek for detailed geometry charts for the SL6 and SLR6.
The styling of the Émonda is very clean and simple with inviting lines that flow from one point to the next. The seat tube junction in particular is elegant and I like the way the seat stays seem to sprout with energy for the dropouts.
Trek keeps the paintwork simple with a minimum of decoration though the gloss paint adds some luxury to the final result. The Émonda SL6 is currently available in a choice of two colours (Matte Trek Black with Gloss Trek Black logos, or, Viper Red with Trek Black logos) compared to one for the SLR6 (Crystal White with Argent Silver logos and Trek Cyan details). However, there are many more paint finishes available for the SLR via Project One.
The SL6 and SLR6 are both dressed with Shimano’s mechanical 11-speed Ultegra groupset and a suite of Bontrager components but there are some distinct differences between the two bikes. For example, the SL6 uses Bontrager’s entry-level Race wheelset while the SLR6 gets an upgrade with a Race Lite wheelset that is lighter.
Similarly, the SL6 is supplied with a Bontrager Paradigm Race saddle with chromoly rails while the SLR6 gets a Paradigm RL saddle that has hollow titanium rails. There is also a difference in brake calipers, where the SL6 has standard Ultegra calipers while the SLR6 uses Bontrager Speed Stop calipers.
All of these differences, from the grade of carbon fibre to individual parts, provide significant weight savings for the SLR6 when compared to the SL6. The SL6 sent for review (size 54cm, H2 fit) weighed 7.42kg sans pedals and cages while the SLR6 (size 54cm, H1 fit) weighed 6.68kg. The savings (740g) can be attributed largely to the SLR frameset (~300g) and the Race Lite wheelset (300g), with smaller weight savings provided by the shorter head tube and a lighter saddle.
Unsurprisingly, the weight savings come at a significant cost: the Émonda SL6 has a recommended retail price of $3,699 while the SLR6 retails for $8,499. In both instances, the frames come with a lifetime warranty while the forks and all Bontrager parts are covered by a two-year warranty. For more information on the Émonda range, visit Trek.
After spending the day riding an Émonda SLR8 last year, Dave Everett found that “the first noticeable thing for me was not so much the weight but how planted the bike felt on the road.” Later though, once he found himself in hillier terrain, Dave was “definitely using the big chainring a lot more” than he normally would thanks to the low weight (6.15kg) of the bike.
Like Dave, I wasn’t wowed by the weight of the SL6 or SLR6. Instead, the Émonda was surprisingly ordinary, even mundane, compared to its marketing hype. Of course, there was more to discover, but after my early rides on the SL6 and SLR6, all I could say was that both bikes offered a very smooth and refined kind of ride that I’ve long associated with Trek’s bikes.
A “refined kind of ride” is not necessarily a compliment though. For those riders that like the bike to disappear beneath them so that they remain unaffected by road feedback, the Émonda should have plenty of appeal, regardless of whether it is the SL or SLR. However, I found myself wanting more from the bike, and while I could criticise the Émonda as being “dead” or “unlively”, that wouldn’t be fair. Instead, I’ll say this: riding an Émonda is like visiting a library to enjoy the quiet.
The steering and handling of the Émonda was very stable and predictable. As such, the bike is incredibly easy to ride. The bike obeyed my every instruction and while the steering tended towards slow, I didn’t find it required any extra effort to hold a line through sharp corners. I wouldn’t recommend the bike for criterium racing but then there isn’t much about the Émonda’s styling or marketing that would likely attract a dedicated criterium racer.
Neither the SL6 nor SLR6 felt like a particularly light or responsive climbing rig. Capable, yes, but still some distance from ever being explosive. What seemed to be missing was any great sense of the bike’s stiffness. It’s not that the bike was too compliant, but rather, I wasn’t getting any feedback from the bike in order to judge its performance. Thus it seems the Émonda is defined more by the absence of any sensation rather than what can be felt by the rider.
The Émonda was well suited to long rides. The bike doesn’t rattle or chatter, even on rough roads, and I found the hours passed by with ease as the bike continued with steadfast assurance. I found myself re-evaluating the subdued ride quality as a comfort, like the support and encouragement from a devoted friend. After all, there’s no need for showmanship on a long ride, just steady commitment from the rider and the bike, and the Émonda was prepared to keep going for as long as I wanted.
By taking turns on the SL6 and SLR6, and then swapping the wheelsets between each bike, I found that the SLR6 was a stiffer bike. It was only a mild difference, but it could be felt when rising out of the saddle on a climb, traversing rough roads, and as a little feedback from the road. Overall, it provided the SLR6 with a racier feel than the SL6, but I must stress, it was very mild. Switching to stiffer mid-profile carbon wheels (Curve 38mm clinchers) enhanced this sense a little more but the wheels weren’t able to transform the Émonda into an aggressive race bike.
The Domane has a strong reputation for its comfort but the Émonda shouldn’t be overlooked, especially the SL series. I found myself marvelling at how well the SL6 was able to soak up every crack, bump and rut. Furthermore, there was a good balance of compliance between the front and rear of the bike. Adventurous riders that enjoy demanding terrain may find the Émonda lacking, otherwise the bike is well suited to a wide variety of terrain.
The SL6 had a lot in common with the SLR6. The overall ride quality was very similar while the steering and handling were identical. I’ve already mentioned that the SLR6 was marginally stiffer; it was also marginally more agile, but that was due largely to the lighter wheelset. Indeed, swapping wheelsets between the two bikes improved the SL6, however it made no difference to the stiffness of the bike.
Finally, I’m pleased to report that Bontrager’s new direct mount Speed Stop calipers are a significant improvement over the previous iteration supplied with the Madone. The calipers were smooth and effective with plenty of bite but they didn’t suffer any of the heavy effort that defined the last version. Indeed, I couldn’t find anything to separate the performance of Speed Stop calipers from the standard Ultegra brakes fitted to the SL6.
My only complaint is with the way the inner cable is routed: it ends up between the tyre and the brake arm to rest upon the brake pad. Cutting the cable short removes any risk of it getting caught against the rim but then is too fiddly to hold when re-adjusting the cable.
The Émonda has been positioned by Trek as an ultralight bike, purpose-built for climbing, with a strong emphasis on race performance. I don’t have a quarrel with their claims or strategy but the bike is much more versatile than a dedicated climbing rig. The ride quality is easy to like and the steering and handling ensure its reliability in essentially any situation, so while it won’t satisfy buyers looking for extremes in performance, it’s hard to see how it will disappoint anybody else.
The differences between the SL6 and SLR6 were modest at best. Some were a matter of the parts specified for each bike, but fundamentally, the SLR frameset is lighter, stiffer and more race-oriented that the SL.
It is interesting to note that most of the weight savings offered by the SLR6 can be obtained for an Émonda SL by upgrading from the SL6 to an SL8 (RRP $4,999) and substituting the stock Race wheelset for the Race Lite version without spending any more than $6,000. I’m not criticising the price of the SLR though, just highlighting what is perhaps the Émonda’s greatest strength, which is Trek’s range of models and options for the bike.