Although their trend status is long gone for sure: Twentyniners are discussed among bikers as intensively as on day one. Some riders guess that the new generation of mountain bikes will completely replace the original 26” concept one day. At the same time, many other cyclists still refuse 29ers due to alleged disadvantages in terms of system functionality and weight. But meanwhile, the truth is – as so often – somewhere between.

Big-wheeled bikes offer some unquestionable physical advantages. When a 29” wheel rolls e. g. over roots or rocks, it hits the obstacle in a comparatively flatter angle and is retarded to a lesser extent. Thus less energy is necessary to master the obstacle. What seems to be only “dry” physical terminology is just “smooth” for the rider: Even 29” hardtails often evoke the riding feeling of a fully. The bigger wheels utilize the same advantage when they roll through the bumps of uneven surfaces: A bigger wheel means less dip – also in this case, a 29er benefits from reduced retarding and the therefore reduced energy expenditure that is necessary to manage the respective riding situation. Third advantage for an entry into a book about physics: At identic BB height (measured from the ground), a Twentyniner’s BB is positioned comparatively lower in relation to the imaginary axis between front and rear wheel hub. Result of this larger “BB drop”: Especially on steep ascents, the rear wheel gets more traction while wheelspin tends to occur at a later point of time. Thus the pilot perceives a lower tendency for “front-end rise”. During steep downhills, the same applies vice versa: The dreaded feeling of flipping over the handlebar occurs later as well. These 29er advantages are especially a great benefit for riders whose technical skills are less advanced.

Twentyniners also offer advantages with respect to a hardtail’s comfort: Longer seat and chain stays mean more flex while the larger tire volume provides improved shock absorption. And the disadvantages? There are some, no question – such as the slightly higher additional weight or the minimally more lethargic wheelset. But nevertheless, especially long-distance bikers will finally recognize a Twentyniner as better concept for their individual purposes.

Bigger, better, more:
Longer wheel base and longer chain stays for more running smoothness – plus more comfort and traction: A 29er’s geometry offers many convincing advantages (illustration not true to scale).