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How is through axle stiffer than QR?
Through axle is an idiotic design - one of several that have become popular in bicycles over the last two decades.
People talk about the stiffness of the through-axle system because it's thicker. That's horseshit. Such arguments show a complete lack of understanding of the forces involved. Every Tom Dick and Harry who builds products for bikes assumes that bigger diameter automatically equates to greater stiffness. This is reliably true for tubes. But not everything else.
First, the skinny quick release skewer doesn't support any weight to begin with. Its sole purpose is to squeeze the hub and dropouts together and keep everything in place via friction, hence, it need only have significant tensile strength, not stiffness. The hub itself has an axle of its own on which the dropout sits. It supports the dropouts vertically. While this QR axle is still narrower than the through-axle skewer, it also does not dictate the stiffness of the hub-dropout connection. When squeezed together with the skewer, the larger face of the hub's axle pressed against the inner surface of the dropout is large, as are the faces of the skewer's cam and acorn nut. The SURFACE AREA being squeezed against the dropouts is what ensures that the hub is held in place and unable to move relative to the dropouts, and vice versa. This is what dictates the stiffness of the system. It has absolutely nothing to do with the diameter of the axle traversing the dropouts.
Furthermore, thru axles must be screwed into place. And anyone with two connecting neurons knows that a cam is a vastly more secure method of maintaining tightness than a screw. The through axle by definition depends on screwing the thing tight enough to create significant friction between the axle and the dropout, which is more difficult to do. It also will produce more damage to the dropout each time it's screwed and unscrewed. A cam merely presses against the dropout.
Through axle is an idiotic design - one of several that have become popular in bicycles over the last two decades.
People talk about the stiffness of the through-axle system because it's thicker. That's horseshit. Such arguments show a complete lack of understanding of the forces involved. Every Tom Dick and Harry who builds products for bikes assumes that bigger diameter automatically equates to greater stiffness. This is reliably true for tubes. But not everything else.
First, the skinny quick release skewer doesn't support any weight to begin with. Its sole purpose is to squeeze the hub and dropouts together and keep everything in place via friction, hence, it need only have significant tensile strength, not stiffness. The hub itself has an axle of its own on which the dropout sits. It supports the dropouts vertically. While this QR axle is still narrower than the through-axle skewer, it also does not dictate the stiffness of the hub-dropout connection. When squeezed together with the skewer, the larger face of the hub's axle pressed against the inner surface of the dropout is large, as are the faces of the skewer's cam and acorn nut. The SURFACE AREA being squeezed against the dropouts is what ensures that the hub is held in place and unable to move relative to the dropouts, and vice versa. This is what dictates the stiffness of the system. It has absolutely nothing to do with the diameter of the axle traversing the dropouts.
Furthermore, thru axles must be screwed into place. And anyone with two connecting neurons knows that a cam is a vastly more secure method of maintaining tightness than a screw. The through axle by definition depends on screwing the thing tight enough to create significant friction between the axle and the dropout, which is more difficult to do. It also will produce more damage to the dropout each time it's screwed and unscrewed. A cam merely presses against the dropout.
