RE:aktiv with Thru Shaft FAQ

RE:aktiv with Thru Shaft is the shock that can keep up. Trek rejected the status quo to improve the immediate response, seamless transitions and uninterrupted terrain tracking that riders have come to love about RE:aktiv.

Instant response, uninterrupted tracking

All-terrain responsiveness is RE:aktiv’s calling card: extra-firm, low-speed compression damping; supple and controlled, high-speed compression damping; and an immediate transition between the two. RE:aktiv with Thru Shaft improves upon this responsiveness.

The unprecedented design of RE:aktiv with Thru Shaft responds to changes in terrain faster than any other shock on the market, providing a constant connection between rider, bike and trail. The revelation that you’ll experience on the trail is a faster, more controlled ride and a shock that you can literally feel going to work beneath you.

How can it be so smooth and fast?

First, you have to understand something called the Internal Floating Piston (IFP). In conventional air shocks, the IFP separates an oil column and an air chamber. When you hit a bump, a damper shaft displaces oil, which moves the IFP, which compresses air in the chamber. Then, the IFP floats back to its original position. This process is what creates lag. Until now, this system has been the standard of efficiency, and it’s still pretty good. But riders today are charging over more technical trails, and they demand a shock with a faster response.

RE:aktiv with Thru Shaft eliminates the need for an IFP and the lag that comes with it. Rather than a separate chamber for compressed air, RE:aktiv with Thru Shaft employs a solid column of oil, a single damper piston and a rod that exits the bottom of the shock during compression. This simplified design does away with the harshness and hesitation that riders often describe when their shock can’t keep up with the terrain. Sometimes, simpler really is better.

1. Main damper shaft
2. RE:aktiv damper piston
3. Internal floating piston and gas charge
4. Solid column of oil with no gas charge
5. Secondary damper shaft

No more lag

Because the Thru Shaft design responds faster and engages terrain more comprehensively, you’ll feel as if your bike and the trail have a telepathic connection, moving seamlessly together rather than constantly challenging one another.

The shock reacts more quickly throughout the stroke. On the trail, you’ll notice suspension that responds to every bump it encounters. This crisp, precise feeling is accentuated by the fact that the rod force created by a traditional IFP damper is eliminated, allowing the rider to experience the full benefits of the suspension system’s kinematics in a way that simply wasn’t previously possible.

A new industry benchmark from industry leaders

Innovation requires a willingness to go further than anyone has before, and Trek’s partnership with Penske Racing Shocks – the undisputed leader of custom motorsport suspension design – bore unprecedented results with the creation of RE:aktiv. Penske was also a major inspiration and partner in the development of RE:aktiv with Thru Shaft, pushing the envelope even further by transferring more proven motorsport suspension technologies to mountain bike applications.

Once Trek’s suspension team and the experts at Penske landed on a basic design blueprint, we partnered with both FOX and Rock Shox to further develop and bring this technology to the MTB market.

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