HiFi Plus 29

Inertia helps explain the difference in handling between a 26" wheel and a 29" wheel. Understanding how inertia affects the larger wheel helped the Fisher team determine how to normalize the behavior of a 29er to that of a G2 26" bike.

Input at Steering
A more dramatic effect of inertia on 29ers is the effect on handling. 29ers have a reputation for steering slowly. The torque required to steer a 29er is 30% greater than that of a 26" bike due to the greater inertia of the bigger wheel.

Fisher has applied the thinking behind Genesis 2 Geometry to overcome this. To overcome the turning inertia Fisher experimented with multiple fork offsets on 29ers.

A crew consisting of Travis Browne, Fisher athletes, and Fisher product developers blind tested several different fork offsets. After several iterations a fork offset of 51mm was settled on as the optimized offset for 29ers. This 51mm offset reduces the trail of a 29er and brings it to nearly the same distance as a 26" bike. The result is a 29er that handles with the same nimbleness of a 26" bike.

The Acceleration Myth
Acceleration is measured by how much force is required to bring the wheel up to speed. There is a small difference between the acceleration of 26" and 29" wheels. However, a mountain bike wheel is little good without the rest of the bike and the much heavier rider on top of it.

Point being, the difference in force required to accelerate a 29er vs a 26" bike needs to take in consideration the total weight of the wheels, bike, and rider. Assuming the same 175lb rider on a bike, the amount of force required to accelerate a 29er vs a 26" bike with the exact same spec is less than 1% difference.

The benefits of the 29" wheel (sustained momentum, better clearance of obstacles, better floatation over soft terrain, improved cornering) outweigh the minimal acceleration force required for a 29er.