New Trek Madone literally blows a hole in bike design with radical shapes that make it faster, lighter and more comfortable

US brand's redesigned aero race bike swaps the IsoSpeed decouplers for hole called 'IsoFlow'

Trek Madone with IsoFlow 'hole'
(Image credit: Trek)

When the Trek-Segafredo riders were asked how the Madone - the aero bike that was at that time in its sixth iteration - could be improved, the reply rang like a popular musical refrain. Faster. Lighter. 

These are recurring themes when it comes to road bike (opens in new tab) design after all. But if the tune heard was a familiar one, the response from Trek’s designers has proven to be far more avant garde.

The latest Madone SLR has met these common issues - namely how to make a bicycle lighter and more aerodynamic - with some singular solutions. The result is a bike that’s been both tweaked and overhauled in a quite extraordinary way.

Trek's new Madone SLR with IsoFlow technology

(Image credit: Trek)

When it first surfaced at this year's Critérium du Dauphiné (opens in new tab), the new Madone made headlines largely due to the radical seat tube design. Gone was the IsoSpeed decoupler that had been introduced to help make the bike more comfortable. In its place was, well, a hole. 

This technology is called IsoFlow. It’s at the heart of the Madone redesign and provided part of the solution to the demands made by the pro riders. By removing the adjustable Isospeed system, the bike became both simpler and lighter. Combined with the use of 800 series OCLV carbon, the new frame weighs 300 grams less than the previous model. 

The effect on the bike’s overall weight means a 56cm Madone SLR 9 with SRAM Red eTap weighs 7.36kg.

Trek's latest Madone SLR with IsoFlow technology

(Image credit: Trek)

And crucially, according to Trek, IsoFlow also makes the new Madone more aerodynamic. “IsoFlow is a way to direct some high energy flow into a low energy region of the bike,” says Trek aerodynamicist John Davis. The seat tube is an area of the bike that creates a lot of drag. The hole reduces this by “introducing a jet of fast moving air”, Davis says.

Trek Madone IsoFlow in the wind tunnel

(Image credit: Trek)

But has IsoFlow made the latest Madone less comfortable? Not so, says Trek. With IsoSpeed gone, the frame is designed to be the “flexing component”. For example, the redesigned top tube features a thinner section in front of the IsoFlow, which adds flex and in turn comfort. 

Trek compares the ride quality of IsoFlow to Isospeed on its “stiffest setting”. So essentially, a little compromise in comfort for a whole lot of gains in the speed department. The new frame is said to be almost 20 watts faster than the last generation, which equates to 60 seconds per hour when ridden at 45kph.

Trek Madone SLR head tube

(Image credit: Trek)

Half of this saving is derived from the new frame design. Alongside the IsoFlow technology, the latest Madone boasts new tube shapes across the entire bike. The redesigned Kammtail shaping is clearly evident and has been developed in part by studying what Davis describes as “unsteady aerodynamics that mimic the real world.” 

To the eye, the head tube is deeper, as are the fork blades. The bottom bracket ‘shelf’ is tall, having been raised to close the gap between it and the bottle cage, which reduces drag in this area.

Trek's new Madone has redesigned headtube and cockpit

(Image credit: Trek)

The other half of those watts, 9.7 of them to be precise, comes courtesy of a change in rider position. To achieve this Trek has overhauled the Madone’s cockpit. The integrated bar and stem sees the shifters moved inwards by 3cm, what Trek calls an “ergonomics decision” that also puts the rider in an optimized position to reduce drag. 

Interestingly the narrow hoods are balanced with bars that are 3cm wider in the drops, with the aim of offering more control. An ‘old’ size 42 bar becomes 39cm at the hoods and 42cm at the drops. Colnago did a similar thing with the new CC.01 cockpit,  introduced with the new Colnago C68 (opens in new tab), which features a similar semi-flared shape. The drops also have a shorter reach and a fresh bend that Trek believes is more comfortable.

The bars and stem have further aerodynamic benefits. The tops of the bars have been shaped to improve airflow, while the brake hoses are now fully integrated to clean up the front end of the bike. And it is just hoses. This latest Madone frameset is only compatible with electronic groupsets, as are many of the latest flagship race bikes.

In total there are 14 different bar and stem combinations available, though Trek has been thoughtful enough to also create a different bearing top cap that then allows you to use the bar and stem of your choice.

The new Trek Madone SLR features a redesigned cockpit

(Image credit: Trek)

So what else do we need to know about the new Madone SLR? It’s available in six models, from the SLR 6 to the SLR 9. It uses the threaded T47 bottom bracket standard, one Trek has embraced across all its new framesets. 

It’s optimized for 28mm tyres, although this is to allow 6mm of clearance, which should mean you can opt for a little more volume should you desire it. It’s also offered in five colourways, including two Trek-Segafredo team versions as well as a lightweight option that’s described as a ‘deep carbon smoke.’

The redesigned seatpost also aims to deliver optimal fitting, with four different combinations offered: two lengths and two offsets. As for seatpost adjustability, there’s an average of around 6cm minimum-to-maximum for each length of ‘mast’.

Trek-Segafredo's Mads Pederson riding the latest Madone SLR

(Image credit: Trek)

The new look Madone SLR will likely receive plenty of air time at this year’s Tour de France (opens in new tab) and Tour de France Femmes (opens in new tab). Derived from the ongoing dialogue between a bike manufacturer and the professional teams it sponsors, it’s a relationship that Trek-Segfredo’s Mads Pederson believes has paid dividends.

“We did this together,” said the 2019 world road race champion in the press release. “From the engineers at Trek to us, working together. They have the data but we have the feeling on the bike, and that combination makes a perfect bike.”

“Now we’re here,” he continued, “ and we’re riding a spaceship.”

Trek Madone SLR pricing

Madone SLR 9 eTap - SRAM Red eTap AXS/Bontrager Aeolus RSL 51 wheels £13,800 / US$13,199.99 

Madone SLR 9 - Shimano Dura-Ace Di2/Bontrager Aeolus RSL 51 wheels £12,700.00 / US$12,749.99 

Madone SLR 7 eTap - SRAM Force eTap AXS/Bontrager Aeolus Pro 51 wheels £9,600.00 / US$9,699.99

Madone SLR 7 - Shimano Ultegra Di2/Bontrager Aeolus Pro 51 wheels £9,150.00 / US$9,049.99 

Madone SLR 6 eTap - SRAM Rival eTap AXS/Bontrager Aeolus Pro 51 wheels £7,450.00 / US$8,399.99 

Madone SLR 6 - Shimano 105 Di2/Bontrager Aeolus Pro 51 wheels £6,850.00 / US$7,999.99 

Madone SLR Disc frameset only - £5,000 / US$4,599.99

For more information visit trekbikes.com (opens in new tab)

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Luke Friend

Luke Friend has worked as a writer, editor and copywriter for over twenty years. Across books, magazines and websites, he's covered a broad range of topics for a range of clients including Major League Baseball, the National Trust and the NHS. He has an MA in Professional Writing from Falmouth University and is a qualified bicycle mechanic. He fell in love with cycling at an early age, partly due to watching the Tour de France on TV. He's a passionate follower of bike racing to this day as well an avid road and gravel rider.