Trek Madone SLR 9 eTap review

Released in summer 2022, the latest Trek Madone SLR is the platform’s seventh generation. Trek says it is its fastest race bike to date, as well as the lightest disc brake Madone too.

Trek exploits the recent relaxation in the UCI’s rules concerning tube dimensions to make the frameset more aerodynamic, but builds on that with an unusually narrow cockpit design.

The new Madone also drops Trek’s Isospeed Decoupler feature in favour of Isoflow, a hole in the seat tube Trek says accelerates airflow and improves comfort by turning the upper portion of the seat tube into a cantilevered beam.

The new Madone successfully combines novel features to make it one of the fastest feeling aero bikes on the market.

The narrow cockpit seems effective at adjusting body position to improve aerodynamic efficiency, while the Isoflow feature retains a good degree of the Madone’s characteristic comfort.

The Madone SLR 9 eTap’s price makes it hard to justify if money is in any way a concern, with buyers recommended to look at options further down the range.

However, if cost is no object, the new Madone SLR is a world-class race bike and fantastic fun to ride.

Trek Madone SLR 9 eTap development

A year or two ago it looked as if the aero road bikes were going the way of the dodo. Race bikes can now be built to the UCI minimum weight limit with enough aero cues to make them fast on the flats as well as uphill.

A brand or two even dropped their aero bikes altogether as a result, and Trek’s own Émonda challenged the existence of its Madone.

It was a concerning time for this iconic platform, but a relaxation of the UCI’s rules concerning tube aspect ratios (profiles can now be deeper for the same width) has breathed new life into the aero genre, and the latest Madone exploits those changes to the fullest extent.

‘The new Madone has undergone a host of changes but in short, it is the fastest road bike we’ve ever made by a considerable margin,’ says Jordan Roessingh, Trek’s director of road bikes.

Trek is backing that claim up quantitatively too, saying the new bike can be up to 19 watts faster than the old one via combination of updated design and positional changes its componentry encourages the rider to adopt.

Trek Madone SLR 9 eTap frameset

While the bike is still unmistakeably a Madone in profile, its frameset receives fully revised set of kamm-tail tube profiles. In areas like the head tube, the frame tube profiles are noticeably deeper in an attempt to better control airflow across the area and beyond.

The bottom bracket shell is also noticeably enlarged. Trek says raising the height of it brings it closer to the bottles, filling in space that would otherwise contributes to generating a wake, i.e. reduce aerodynamic efficiency.

Despite the bulked-up frame, the new Madone is said to be around 300g lighter than before. Trek credits an increase in structural efficiency, i.e. simpler shapes and a revised carbon layup schedule.

That said, Trek has given that figure across the whole frame module, meaning it can factor in the cockpit going to one-piece from two (which accounts for around half the saving) and refinement in sub-components, such as a new seatpost clamp.

The move to the Isoflow hole from the Isospeed Decoupler mechanism helped drop weight too.

Citing the level of adjustment Isospeed offered as being unnecessary, Trek used the Isoflow feature to turn the top portion of the seat tube (or is it a kinked extension of the top tube?) into a cantilevered beam in order to generate the comfort the Madone is famed for.

Isoflow is said to reduced drag by around three watts by allowing airflow into the low-pressure area behind the rider too, as well as being simpler and lighter than Isospeed.

The Madone is still solidly positioned as Trek’s raciest offering, yet the brand has built in healthy levels of tyre clearance (albeit unofficially). The ‘recommended’ tyre size is a conservative 28mm, but Trek says that is with 6mm of space around the circumference of the tyre, meaning should the rider go rogue, it is possible to fit much larger sizes in.

A removable front derailleur mount also adds to the bike’s versatility in my eyes – I think a wide-tyred, 1× Madone build would be a really interesting bike.

Trek Madone SLR 9 eTap build

The Madone’s new one-piece cockpit is ostensibly as much of a talking point as the frame itself. Trek claims the bar/stem’s design is resposible for half the aero advantage of this bike compared to its predecessor.

Bar width measurements are taken centre-to-centre from the drops, but they are flared so the tops are cumulatively 3cm narrower than the bars’ stated width.

The drops are also more compact, so the rider is more inclined to spend more time in them, according to Trek.

The profile of the cockpit has also been tweaked with respect to the rider being downstream in the airflow – according to Trek it tries to favourably control the airflow to reduce drag on the rider.

I’d suggest the ergonomics of the bar and the position they encourage the rider to adopt is orders of magnitude more important, but provided that isn’t compromised every little helps.

For those bemoaning the apparent backwards step in adjustability the new one-piece cockpit brings, Trek says it will offer 14 different sizes of cockpit to help riders find the best fit, and the bike also accepts a standard bar and stem combo if you swap to a different headset top cap.

It is great to see Trek to take a holistic approach in this respect, given how important rider fit is in overall aerodynamic performance.

Cockpit aside, given that the build on test sits at the top of the Madone’s range its spec list is unsurprisingly hard to fault.

SRAM’s Red eTap AXS groupset provides a wide range of closely spaced gears, and Bontrager takes care of the rest of the componentry.

The brand’s Aeolus RSL 51 aero wheels seem like a solid proposition all round.

They have a lifetime warranty for the original owner and are light for their depth at a claimed 1,410g. They’re built onto hubshells that used DT Swiss’ well regarded 240 internals and their 23mm internal width seemed to pair very smoothly with Bontrager’s R4 320 tyres, which is something said to promote aerodynamic efficiency.

Rim-pairing aside, despite their comparatively small 25mm width, the performance of the tyres themselves was fantastic. Their polyamide synthetic fibre reinforced cotton sidewalls and tacky rubber tread provided an excellent sensation of suppleness and grip. I’d imagine opting to move up to a 28mm version of the tyres would only exaggerate these attributes.

I think Trek’s seatpost solution in the new Madone is neat. The Isoflow design necessitates a non-standard seatpost assembly but rather than opt for a seat mast, Trek uses an expanding wedge in the seatpost itself, accessed via slots in the back of the seat tube.

The design provides plenty of scope for height adjustment, and fixing the seatpost in place was quick and simple, with no access issues.

Trek Madone SLR 9 eTap geometry and sizing

Trek has used the same H1.5 fit it first introduced on the previous generation Madone, which splits the difference between its long and low H1 fit and more upright H2.

Trek makes the valid case that the eight sizes it offers, combined with that Goldilocks geometry, as well as a multitude of cockpit options and seatpost options (two lengths, two offsets) should ensure a good fit for the vast majority of people.

It also means Trek can get away with using one set of moulds, as opposed to requiring two moulds per size. Moulds are very expensive to produce.

Lever reach is affected by the narrower cockpit, effectively making it a touch shorter. Trek says it isn’t enough to dramatically change stem length requirements, however for those looking to achieve an aggressive position and make the most of the cockpit’s narrowness it is something that should be factored in.

Riding the Trek Madone SLR 9 eTap

The bike looks like a rocket ship stood still and out on the road is as fast as is appearance would suggest. Even faster, actually: I’d say the way the Madone goes about achieving that speed is more indirect than its looks make it seem.

While the hugely extended tube profiles on the frameset undoubtedly help, it is obvious while riding the bike that the Madone is able to create the speed it does in large part thanks to the position its bar/stem combo encouraged my body to create.

Trek explains that the bars are 3cm narrower on the tops for a given size, so this 42cm bar (measured centre-to-centre on the drops) is 39cm on the tops.

An equally important feature is the shape of the bend at the top-to-drops transition too, which actually positions the lever hoods at an inward cant as well. Taking into account the additional reach from the tops to my regular hand position on the hoods, that’s cumulatively another 2-3cm inboard of the widest point on the bar tops.

That means the effective width of this Madone’s 42cm bars is around 36cm. Bars that narrow, combined with a stem+bar reach that is long for its width, positioned my wrists such that it encouraged me to tuck my elbows in, which in turn coaxed my shoulders and head down lower as well, without conscious effort.

My natural ride position suddenly became noticeably more aggressive, and I’m certain it’s this set of circumstances which allowed me to go as fast as I did for a given effort on the Madone.

In comfort terms, while the only way to be certain would be some back-to-back testing, I’m fairly confident that the new Madone is decidedly firmer at the rear than its predecessor, which is something Trek says is the case too.

The new cantilevered seat cluster arrangement still definitely works to take the sting out of the bumps, but one way of expressing the resultant ride feel would be to say that it is clear that the area is now structurally attached to the rest of the bike rather than mechanically disassociated, like the last generation.

The new Madone takes care of speed and comfort consummately, but it isn’t without one or two ride feel quirks.

The large second moment of area afforded by the Madone’s enlarged tube profiles contributes to a stiff-feeling frameset, although they do make the bike a bit of a handful in gusty conditions. There is a lot of tube surface area for wind to push against so, for example, riding past gate openings in high hedgerows in a crosswind does have a noticeable effect on the bike.

What’s more, while they are unequivocally beneficial on all other terrain, the narrow bars take some getting used to when tackling steep hills. While climbing out of the saddle I was aware of the lack of leverage the bars provided, making the action a little more awkward than it would usually be. That said, ultra-narrow bars don’t seem to hold track sprinters back, and the aero benefits are well recognised.

Trek Madone SLR 9 eTap verdict

While the seat tube cluster was adjusted to shed weight – and contributes to the claimed 300g saving in the new bike – I do I have my concerns about it.

I’m no structural engineer and Trek says there no durability issue with the design, but I can’t help but wonder what that engineered flex would do to the composite integrity over the long term, e.g. 5 years or more.

The Isoflow hole raises similar structural questions. Can it be that important to drag reduction to outweigh the considerable increase in fabrication complexity that must create for Trek’s manufacturing partner?

Given how effective the bike is at creating a more aero body position, I’d be inclined to suggest the bike could have done without it, reverted to a more conventional seat tube cluster and saved even more weight.

Then there’s the issue of price. While the unsettling fact remains that the Madone’s asking price is now not unheard of, £14,500 for the SLR 9 eTap spec is a spectacularly large sum of money.

It’s a cost that excludes an exceptional number of potential customers. If budget is even the slightest priority, I couldn’t justify recommending this particular bike.

If anything, to an extent the Madone is its own worst enemy, as it demonstrates how effective a simple reduction in bar width can be in terms of making the rider go faster. It is a move that could be made inexpensively on the rider’s existing bike, albeit perhaps not one with as much efficacy without the Madone’s overall design supporting it.

In fairness, Trek does offer a comprehensive range of specs that extend down to the comparatively more accessible £7,600. It’s reasonable to expect a version of the frameset using a lower-grade carbon composite too in future, which will drop the price of the bike to more realistic price points, and the old bike is going to remain available at lower price points too.

With all that said though, moving back to the new Madone in its SLR 9 eTap spec specifically: if money is no object and you want speed without compromise, buy this bike. It feels that fast, you aren’t likely to regret it.

• For more information about the Trek Madone SLR visit trekbikes.com

Trek Madone SLR 9 eTap spec

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Image credits: Lizzie Crabb

Geometry chart courtesy of Trek