Trek just unveiled a new proprietary rear shock technology that will be used on its high-end 2018 Fuel, Remedy, and Slash full suspension trail bikes. Building on their partnership with Penske Racing Shocks, the updated RE:activ shocks eliminate the internal floating piston (IFP) in favor of a fixed shaft that runs the entire length of the shock. The IFP functions to compensate for the change in oil volume as the damper shaft enters the air canister.
With the new Thru Shaft design, the IFP and associated nitrogen charge are gone, allowing for a constant oil volume. Trek claims this improves the shock’s responsiveness, letting the rear wheel react to terrain faster than before. Since the shaft actually exits the bottom of the shock when compressed, this isn’t something you can slap on any bike. Both RockShox and Fox will be supplying Trek with Thru Shaft shocks on select complete bikes and framesets. Look for them to start showing up at Trek dealers this August.
Additional details on the new Thru Shaft shocks are available on Trek’s website.