Trek has launched what it describes as “the fastest and lightest Madone SL ever”, the new models featuring IsoFlow technology, the distinctive seat tube design that was introduced on the top-level Trek Madone SLR last year with the aim of reducing aerodynamic drag and improving comfort.
“This new addition to Trek's ultimate race bike line-up is available at a more affordable price point thanks to a 500 Series OCLV carbon frame, two-piece flared RSL aero handlebar and RCS Pro stem that keeps things light, fast and a bit more economical while maintaining the bike's premium aesthetics and podium-topping performance,” says Trek.
The existing Madone SLR uses Trek’s higher-grade 800 Series OCLV carbon and an integrated handlebar/stem. Whereas stock Madone SLRs start at £7,600 (for the Shimano 105 Di2-equipped SLR 6), Madone SLs are priced from £5,625 (for the Madone SL 6, also fitted a Shimano 105 Di2 groupset).
Trek says these are the only differences between the Madone SL and the Madone SLR. The tube profiles and geometries are exactly the same.
The IsoFlow technology – which takes over from the IsoSpeed found on previous Madone SLs – means that the tube splits in two, each section going on to join one of the seatstays. The seat tube then resumes out of the top tube to house the aero seatpost. IsoFlow is designed to improve aerodynamics, flex over bumps to smooth the ride, and save weight over previous Madones.
When IsoFlow was introduced on the Madone SLR, Trek’s senior design engineer Alex Bedinghaus said, “We can accelerate the air around the head tube and into this low-pressure zone behind the rider, making the rider and bike more aerodynamic and faster.
“It also has this cantilevered seat tube and really optimises weight, aerodynamics and compliance. It’s a unique solution that gets us to a lighter weight system than what we had before, and beats our aerodynamic goals by quite a bit.”
Trek says that this seventh-generation Madone SL is nearly 300g lighter than the previous version and “54 seconds per hour faster at 45km/h [28mph]”. Obviously, that statement doesn't quite make sense; what Trek means is that improved aero efficiency means you’ll ride faster than 45km/h for the same power output on the new bike.
Each Madone SL Gen 7 model is built up with a separate Bontrager RSL Aero handlebar (a flared design with a reach of 80mm and a drop of 124mm) and Bontrager RCS Pro stem rather than the combined unit found on the Madone SLRs. That said, the Madone SL is compatible with the Madone SLR bar/stem if you want to go down that route in the future, you just need to use the right bearing cover and spacers.
The Madone SL Gen 7 is compatible with electronic drivetrains only, so we won’t see a Shimano 105 12-speed mechanical model when that new groupset is finally released.
As previously, Trek uses a T47 threaded bottom bracket. The Bontrager wheels specced on the Madone SL Gen 7 bikes are tubeless compatible, but the bike ships with standard inner tubes and non-tubeless compatible tyres and rim strips.
The saddle height is still adjustable (you have about 7cm of height adjustment) and you can choose between a short or a tall seat mast.
The Madone SL is built to Trek’s race-focused H1.5 geometry with all of the key measurements being exactly the same as previously.
The 56cm model, for example, has an effective top tube of 559mm, a seat tube of 525mm and a head tube of 151mm. The head tube and seat tube angles are 73.5° and 73.3°, respectively. This frame has a frame stack height of 563mm and a reach of 391mm.
Trek offers eight frame sizes from 47cm to 62cm
Madone SL 6 Gen 7
Groupset Shimano 105 Di2
Wheels Bontrager Aeolus Elite 50
Claimed weight 8.40kg/18.52lb (size 56cm)
Madone SL 7 Gen 7
Groupset Shimano Ultregra Di2
Wheels Bontrager Aeolus Pro 51
Claimed weight 8.00kg/17.64lb (size 56cm)
Madone SL Gen 7 frameset
Claimed weight 1200g (frame only, painted, 56cm), 476g (fork only, painted)
There are currently no SRAM-equipped versions of the Madone SL Gen 7, which is really odd for Trek. We assume they'll be coming at some stage but we're going to need to check that.
Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.