Rolling out of the bike industry in the early 2000s, the Thru-axle hub was created to take rider’s bicycle performance levels to the next level. Utilizing a two-piece axle system, the thru-axle hub replaced the traditional quick-release axle (QR) system that was used in the earlier years. Although the QR system is still widely used today, the thru-axle hub quickly gained in popularity for its increased ability to handle higher torque and stress from pedaling while also providing a more secure and stiffer wheel fit.
The primary function of the thru-axle hub is to provide increased stiffness and stability when riding. This has the dual benefits of allowing increased control over the bike as well as helping to absorb the bumps and vibrations when riding on rough trails. The thru-axle hub utilizes a two-piece setup, consisting of a hub-mounted axle, which is composed of a center locking bolt that mates with the frame’s wheel axle post, and the threaded end of the hub, which extends through the frame and mates with a corresponding threaded nut or drop-in nut found on the bike’s fork or frame. This ensures that the wheel is securely held in place and prevents it from becoming loose or becoming too loose from an incorrect fit, something that could cause the wheel to come out of alignment or to wobble when ridden.
When compared to the QR axle hub, the thru axle hub offers increased levels of rigidity, stiffness, and stability. This increased rigidity is due to the increased surface area contact between the wheel and the frame. The contact is increased because of the larger diameter of the axle compared to the smaller diameter of the QR axle. With this increased contact area, more even power distribution is achieved when pedaling. In addition, this greater rigidity results in greater levels of efficiency and responsiveness when cornering and when riding out of the saddle.
On top of the performance gains, thru-axle hubs also offer additional benefits in terms of convenience and weight saving. Convenience-wise, the absence of the QR nuts means there is no longer a need for regular re-tightening of the QR nut. On the other hand, the thru-axle system results in lesser components, resulting in overall lighter wheel setups compared to QR systems.
While the thru-axle hub has become increasingly popular as an aftermarket upgrade for race-level mountain and road bikes, not every bike has the necessary clearance for a thru-axle hub installation due to its larger diameter. Fortunately, the thru-axle hub is also available in the more commonly used QR hub sizes, such as the 15mm, allowing compatibility with the latest performance bike frames and forks.
Overall, the thru-axle hub offers improved performance characteristics compared to the QR hub, such as improved rigidity, increased stiffness, and a more secure and efficient fit. Its relative ease of installation and weight-saving features further make it a great aftermarket upgrade from an overall performance and convenience perspective. Therefore, for those riders looking for greater stability when riding trails or for increased performance speeds on the roads, the thru-axle hub is a great option to consider.