Sign up for our newsletter


Trek Emonda SLR and SL 2021: all you need to know

19 Jun 2020

Trek claims new Emonda SLR & SL models offer balance of low weight and aerodynamic performance to be faster on the flat and uphill

The 2021 Trek Émonda has been launched in what should have been the final few weeks before the Tour de France, where we would have seen the Trek-Segafredo riders aboard this lightweight climbing bike in the high mountains.

With racing postponed, assuming it is to return at all this year, Trek has pushed ahead with the launch of the 2021 Emonda regardless.

Trek’s trio of top tier road race bikes is pretty easy to understand: Domane (pronounced Domané) for comfort, Madone for outright speed and Emonda for lightweight.

For the latest Emonda, now in its third generation, Trek says it has managed to pry just a little bit more of those traits from its siblings while still being the lightest in the line up by a considerable margin.

A quick recap; the first generation of Emonda was launched in Harrogate, Yorkshire, back in 2014, just as the Tour de France rolled into town.

Émonder in French is a verb meaning ‘to prune’, or trim, and nothing could be more fitting for this particular bike. Trek went all out on weight-shedding to create the lightest production bike in the world at the time and, crucially, achieved this without sacrificing ride quality.

At just 4.6kg the top of the range Emonda SLR 10 was indeed an astoundingly light race bike, although it did cost £11k, even six years ago.

The first generation, however, was launched as a rim brake bike, as disc brakes hadn’t taken such a firm stronghold in the road market at that time, so it wasn’t long before a disc brake update was required.

Buy the new Trek Émonda from Trek Bikes from £2,275

A redesign for discs, then, was the obvious catalyst for the second generation of Emonda, for which Trek managed to shave off yet more weight (the top tier SLR disc brake frame was 665g disc frame vs 690g for the equivalent rim brake frame), whilst also claiming to have made the frame stiffer.

So where to go from there? A 665g disc brake frame surely means there’s not much scope to go lighter, so what can we expect from the 2021 Trek Emonda?


A clean sheet start for the 2021 Trek Émonda

Speaking to Cyclist at the virtual launch, Trek’s head of industrial design for road products, Hans Eckhom, had this to say about the new Emonda.

‘Basically this new Emonda was a request from the Trek-Segafredo team. The riders love having the option to race on our various platforms [Madone, Émonda, Domane] but weight is such a tangible thing, and such a focus for elite athletes, so often the racers want the lightest, which of course the Emonda is, but they felt that versus some of the other bikes in the pro peloton it was well behind on aerodynamics.

Buy the new Trek Émonda from Trek Bikes from £2,275

‘We had exposed cables, less integration and the frame was not fully optimised for aero. So the big push for this new bike was to keep the weight low, maintain the ride characteristics that the Emonda is known for and that the team riders really love, but push towards the aero gains we have learned from the Madone.’

Trek’s aero guru, John Davis, takes up the conversation. ‘We didn’t want to just end up designing something close to the Madone, but a bit lighter. We went with a clean sheet start. The focus was to really study the balance of weight versus aero drag on an incline, for which we chose the average gradient of Alpe d’Huez, 8.1%, as the benchmark.

‘HEEDS [Hierarchical Evolutionary Engineering Design System] optimisation software allowed us to track the ideal blend between weight and aero, but also consider "unsteady aerodynamics".

'That is to say, aerodynamics where speeds are much slower and the bike is moving a lot side to side, such as when climbing. It’s a different solution than for, say, our SpeedConcept TT bike, where we need to optimise for going faster when there is less tangential movement of the bike and it’s going in mostly straight lines.

‘Most areas of opportunity for aero gains are at the front, before airflow gets messed up by the legs,' continues Davis. ‘We spent a lot of time on headtube, downtube and bar/stem shapes. The meat of the design process happens in CFD, as it’s simply much more time efficient.

'We can plug new things in and try new things that you can’t do in a wind tunnel. But the wind tunnel is still the authority on whether something is faster in the real world so we still did full wind tunnel tests on this Emonda.’

And the result? Trek claims the 2021 Emonda SLR has 180g less drag than its predecessor. In real-world terms that equates to around an 18W power saving, which Trek has calculated to be 60 seconds per hour faster on flat roads and 18 seconds per hour faster up Alpe d’Huez.


Thanks to a brand new grade of carbon too, nudging Trek’s OCLV nomenclature up from 700 to 800, the frame comes in at a smidgen under 700g.

Trek’s director of road product, Jordan Roessingh, gives us the low-down on the all new frame material.

‘OCLV 800 had about a two year development cycle and we’ve broken over 250 frames on the way to working out how best to leverage the benefits of this new carbon,' he says. ‘We used the race team throughout the development process. With riders like Vincenzo Nibali blind testing on prototypes and so on.

‘Usually going to more aero tube shapes means frames get heavier, but the OCLV 800 is 30% stronger, meaning we could use less of it, which resulted in a 60g weight saving versus OCLV 700, and we were still able to hit all our stiffness and strength test criteria.

'We set ourselves this sub 700g target, and so new materials and new processes were the only way to hit that goal. Which we did. Just. A size medium is 698g.'


The 2021 Trek Émonda is bucking some recent trends

Got any questions? Well, actually yes, we did...

Trek states the maximum tyre clearance for the new Emonda SLR and SL models as 28mm, and all bikes come supplied with 25mm rubber. That seemed curious to us, given the trend in almost all Trek’s competitors has been to push for wider clearance for up to 32mm tyres.

We posed this question to Roessingh, who responded by saying, ‘We still believe 25mm tyres to be the fastest set-up aerodynamically, and whilst 28mm tyres do have benefits in other aspects of the ride quality, this bike was about race-level performance.’

Another trend Trek has eschewed is the move to dropped seatstays, something that many brands have claimed is a proven aero benefit.

Again in response, Roessingh said, ‘We did a lot of investigation, but we found that having the seatstays higher up the seat tube is still the structurally most efficient way for us to make the frame. We would agree that there are some aero gains [to dropped seatstays] but it would add weight, and we would not be able to hit the sub 700g target.'

Finally, will there be a rim brake version? Categorically, no. Trek has gone all in on disc brakes for the new frames.


Émonda, the sum of its parts

But there’s more to the story than just the frame alone. Trek, like most brands, now recognises that a bike’s performance relies on the sum of its parts, a system of components that all need to work together.

‘To optimise speed you simply have to include things like wheels and the handlebar and stem combo’, says Roessingh. ‘We took the same approach with our new Bontrager Aeolus RSL bar-stem system as we did for the frame; to balance weight versus stiffness and aero performance.'

The result is the new Aeolus RSL bar-stem is 160g lighter than the one Trek produced for the Madone.


‘But we also considered practicality and serviceability too. We realise that more integration does make it harder for mechanics to work on stuff and swap components so we have given that a lot of consideration. You can swap out this bar-stem combo without having to disconnect any cables, and you can fit a standard aftermarket stem too.’

While we are on the subject of practicality, it’s interesting to note that Trek has moved away from its own BB90 bottom bracket standard on this new Emonda frame.

Buy the new Trek Émonda from Trek Bikes from £2,275

Instead the Emonda uses a threaded T47 bottom bracket. ‘We used it on the new Domane last year, and it’s an open standard to the rest of the industry,' says Roessingh. ‘We recognise that press fit is not the best solution. A tooled/threaded interface is definitely an improvement. It also means the frame is now compatible with all spindle and crank systems.

'Crucially, though, the T47 bottom bracket shell still allows us to have the same wide down tube stance width.’

Wheels are a huge piece of the aerodynamic pie and as such you’ll find brand new Bontrager Aeolus wheels on the new Emonda SLR and SL models too, as product manager, Claude Drehfal, explains.

‘The new top-end Aeolus RSL 37 wheels are just 1350g per set, which is 55g lighter than our previous best Aeolus XXX2 wheels. The new rim shape is significantly faster too, with around 17% less drag, which means this 37mm rim profile almost matches Bontrager’s 47mm deep Aeolus XXX4 wheels in wind tunnel tests, but offers greater versatility for more use in more varied conditions.

‘The new DT Swiss 240 hubs are not just very light but also a little wider across the flanges which increases the bracing angle to improve stiffness, which in turn meant we could take a bit of material out of the rim and still keep the wheels strong and stiff,' says Drehfal.

There are actually three new wheelsets being launched alongside the new Trek Emonda SLR and SL range, to cater for all the price points. The Aeolus RSL 37 sits at the top of the tree, with the Aeolus Pro 37 (using a lower level DT Swiss hub) and then Aeolus Elite 35 (a lower grade carbon rim) making up the trio.

All three new wheels are tubeless compatible and are covered by a lifetime warranty and two year crash replacement.


Fit to drop

Alongside all of the new features, Trek has also tweaked the geometry to modify the fit of the latest Emonda SLR and SL models. It calls the new fit H1.5.

As anyone familiar with Trek’s previous geometry and fit offerings (H1 and H2) will be able to guess, the new H1.5 fit sits halfway between them. This is great news as often the H1 fit was just too aggressive for us mere mortals to cope with, while the more endurance focussed H2 fit was significantly more relaxed. This halfway house, then, should be spot on.

Trek still describes it as a ‘race fit’, as it says the set up can still be very aggressive, but also allows it to be just that bit more attainable for regular riders too.

Buy the new Trek Émonda from Trek Bikes from £2,275

While we are on the subject of geometry there will be no women-specific models. Trek now sees the fit as ‘gender neutral’ and across all its Emonda SLR and SL models the only changes are shorter cranks, stems and narrower handlebars on the smaller frame sizes.

Directly linked to the fit is, of course comfort and in this regard Trek has not gone down the route of adding the IsoSpeed concept, as seen on its latest Domané and Madone bikes.

This was presumably to avoid any additional weight, but also Trek already claims its seatmast design is already significantly more vertically compliant that a standard seat post, and so comfort should not be an issue.

Project One

Trek’s Project One customisation programme is growing in its vastness of available options you can personalise.

Essentially the scope is now huge, to not just make sure the bike you buy fits you precisely – you can tailor things like crank length, bar width and so on – but also to select from 49 different custom paint schemes.

Project One Ultimate is a new offering and takes things a level further. This includes dedicated time with one of Trek’s graphic designers for, and we quote, ‘No holds barred’ levels of paint customisation.

You might not feel the need, however, with some pretty fancy new stock colour schemes, which Trek calls Icon, one of which even contains real 22 carat gold leaf flakes in the paint.


Trek Émonda SL

Joining the top end SLR models in the Emonda family are a host of new SL models too.

Trek says the SL frame is identical in every way to the SLR, with the only concession being it’s created using Trek’s lower tier OCLV 500 carbon. As such it weighs more – around 1100g – but as for the ride qualities and aero benefits, Trek’s engineers claim they have ensured these have all been retained.

One obvious omission from the spec of the SL models too is a one-piece Aeolus RSL bar/stem. All SL models are all specced with traditional bar and stem set-ups.

Trek Émonda SLR and SL 2021

Browse the entire Émonda range at Trek Bikes here

Trek Émonda SLR

Émonda SLR 6 - £5,450
Émonda SLR 7 - £5,900
Émonda SLR 7 eTap - £6,850
Émonda SLR 9 - £9,700
Émonda SLR 9 eTap - £9,700

Trek Émonda SL

Émonda SL 5 - £2,275
Émonda SL 6 - £2,900
Émonda SL 6 Pro - £3,350
Émonda SL 7 - £4,850
Émonda SL 7 eTap - £5,250

The bikes are available to buy immediately

From £2,275

Read more about: