What is Trek IsoSpeed Technology?

Part comfort, part suspension, Crank Boutique explains one of Trek’s key pieces of proprietary bicycle technology.

Technology In Short

While compliance and “suspension” systems are now not uncommon for road bikes (see Specialized’s Roubaix and Diverge), arguably Trek were the first mainstream brand to integrate these systems into some of their key models.
  • Manufacturer: Trek
  • Technology Type: Suspension, Compliance
  • Availability: Proprietary – Trek bikes only
  • Cost: N/A. Isospeed tends to come only on higher end models
  • Current Road/Gravel Models: BooneCheckpointDomaneMadone

What is Trek IsoSpeed?​

To the casual observer the biggest difference between road and mountain bikes has been the size of the tyre and attached suspension. Over the last few years however, these strict definitions have started to erode in the pursuit of adventure and comfort. With the former 700c tyres get wider every year and the gravel/adventure category mean bigger tyres for everyone. With the latter a number of manufacturers have introduced “suspension”” platforms in their road bikes, including BMC, Wilier, Specialized and Trek’s IsoSpeed.

While the term “suspension” may be mis-leading, the IsoSpeed system is designed to provide riders with more comfort and control over rougher surfaces and was originally designed by Trek to give their bikes and riders an edge in the Classics – e.g. the Paris-Roubaix. The system works by “decoupling” key parts of the bike to provide more compliance and less rigidity – resulting in a more comfortable ride. IsoSpeed is one of the most mature road “suspension” systems out there, debuting in 2012. The Trek IsoSpeed system has two components:

Rear Decoupler (Top Tube/Seat Tube)

The IsoSpeed Read Decoupler is a essentially a “hinge” that sits between the seat tube and top tube of the bike. On IsoSpeed equipped bikes the seat tube and top tube are not physically attached but are mechanically joined by the rear decoupler. This means that the seat tube has a range of rearward moving helping to absorb the shocks of riding on things like cobbles, rough roads or gravel. There are a couple of implementations of the platform depending on the bike model – the Emonda uses a slightly different implementation with more adjustment along the top tube owing to its unique frame shape and rarefied price point…

Front Decoupler (Headset)

The front decoupler is slightly more complicated. The Front IsoSpeed is a proprietary headset collar with a rocker that sits in the top of the head tube and bolts into the steerer tube via an assembly that includes a couple of bolts and a preloaded spring. Obviously you won’t be railing berms or going down a double black on it, but this setup allows for a degree of back and forth movement in the steering tube and help to deflect some of the chatter out of the handlebars.

Note that some bikes may have the rear decoupler without the front headset decoupler.
IsoSpeed is available across Carbon and Aluminium models in the Domane and Madone ranges. It is also available on a number of Trek CX and gravel models (including Boone and Checkpoint) and some of their XC MTB range. Watch some videos of the system in action below.

This video from Peloton TV is on an older model – check out the classic Dura Ace – but it’s a perfect introduction to how the Isospeed de-decoupler works in practice.








2019 Trek Madone SLR 9 Disc
The very fast and very beautiful Madone SLR 9. IsoSpeed Flagship.

Does Trek Isospeed Work & How Has It Reviewed?

The CrankBoutique team have only had occasion to ride one IsoSpeed equipped bike – a Domane on some very smooth roads south of Sydney. Lovely bike as it was we can’t really comment on its comfort chops on rough roads although we certainly didn’t get any loss of power.

We haven’t found any reviews of the system in isolation, but there are a few comparative reviews of IsoSpeed equipped bikes vs competitors, including Specialized’s Future Shock:

2018 Trek Domane SL 5 Review

The first time you hit a patch of corrugated or fractured tarmac you understand what IsoSpeed does. Rather than undulations deflecting the front wheel, it absorbs and nullifies the effect of quite big hits, keeping the wheel straight and giving a smoother ride. The rear end removes jarring vibrations that can fatigue muscles faster, helping you ride for longer…IsoSpeed’s bump absorption irons out small undulations to allow the 25mm tyres to grip more consistently, and even though the Bontrager rubber measures 26mm on the 28mm wide rims, if unaware, you’d think you were riding on 28mm tyres.

Trek Madone SLR 9 Disc Review

I've ridden the Trek Madone SLR 9 Disc in various IsoSpeed modes to discover what difference to the rear it would make. I learnt that I probably wouldn’t ride in the stiffest setting as it was a little too harsh at the rear for me.

Towards the middle and softest setting was my preferred mode and I could altogether forget I was riding such a racing machine, let alone an aero road bike that more often than not is too hard to ever be called comfortable. To be frank about the bike’s stiffness, I couldn’t really tell that I was getting anything less from the bike in the softest setting, it still whipped up a storm no problem.

2018 Trek Boone RSL Review

I quickly noticed the compliance provided by the front IsoSpeed decoupler. The front end of the Boone softened the park bumps and helped absorb some of my less-than-stellar moves on singletrack. Especially given my bad back, having some shock absorption on the front improved the ride quality….Smoothing out a ride is one thing, but does the front IsoSpeed handicap actual racing by hindering accelerations out of corners or finishing sprints? I pushed the Boone RSL frame through several practice sprints and found the only limiter to be my lack of sprinting pop.

2020 Trek Domane First Ride Review

If you’ve been thinking about a new all-road bike and holding out as one of the skeptics of Trek’s IsoSpeed concept in general, though, feel free to quit sitting on your hands and just go ride one already. IsoSpeed has never been an empty gimmick, and this latest incarnation sure does seem to be Trek’s best interpretation to date.

2020 Trek Domane SLR First Ride Review

No doubt about it – the IsoSpeed system is impressive. That said, we question whether so much technology (and compromises in terms of cable routing) are needed to improve comfort. On balance and purely in comfort terms, the answer is probably no. After all, there are other bikes that offer the same or even better comfort levels. However, in terms of individualisation and tuning it to the rider’s weight, the IsoSpeed system offers an effective solution and will wow tech enthusiasts who appreciate the packaging of complex technology into a classic and inconspicuous design. Set up correctly, it results in well-balanced comfort between the front and rear and convincing vibration damping!

Are There any Known issues with Trek IsoSpeed?

While IsoSpeed has been well-received by the press – and we also assume the pros – we know that some of these ride enhancing features are not always received well by the traditionalists out there. While Trek has made pains to point out that IsoSpeed is not a “soft tail” system like the offerings from some manufacturers, there is still a stigma around loss of performance from any kind of decoupling.

Reviewing social and search data we note that the following issues which may be worth asking your dealer about before you buy:

Some users report that IsopSpeed equipped headsets have excessive creaking – see link above.

Some users report that IsopSpeed equipped bikes have excessive cable rattle – see link above.

Some users report that IsopSpeed equipped bikes required additional bearing maintenance – see link above.