TT Bike Stack and Reach

Time Trial (TT) and Triathlon bike stack and reach differ fundamentally from road bike metrics because the primary contact points are the aero bars, not the hoods. On a TT bike, frame reach is often slightly shorter to account for the forward-leaning aero position, while the stack is significantly lower to get the rider’s head and torso out of the wind. However, the industry has largely shifted toward using Pad Stack and Pad Reach as the primary fit metrics for these bikes.

A TT bike with a “low” frame stack allows for the most aerodynamic potential but may be unrideable for an amateur. Therefore, most modern TT bikes feature highly adjustable integrated cockpits. The goal of TT stack and reach is to find the “sweet spot” where the rider is as low as possible without closing the hip angle so much that power output drops or breathing becomes restricted. Because TT bikes handle differently, the reach also factors into how much weight is over the front wheel, which is critical for stability when riding in deep-section wheels or crosswinds.