The compatibility of wheels is history. If you want to fit your old wheels on a new bike, you usually fail because of the axle standard. Classic 5-millimetre quick-releases, once a popular tuning part, no longer fit into modern forks and frames. But innovation has its advantages: Large-volume (thru) axles increase system rigidity and steering precision, while the QR15 thru axles speed up wheel removal on the front wheel.
The classic quick release
Quick-release skewers have a lever and a lock nut. They sit in a 9 mm (front) or 10 mm (rear) hub body, which absorbs the loads. The DT Swiss Thru Bolt is the exception here. It absorbs the external forces itself.
QR12 thru axle
Current bikes are increasingly being fitted with 12 mm thru-axles at the rear. They are stiffer and in some cases easier to operate. They are either clamped without tools or using a hexagon socket spanner.
QR15 thru axle
The lightweight 15 mm QR thru axle is mainly used on bikes with up to 150 mm suspension travel. It is bolted to the fork without tools using a clamping lever and is characterised by simple operation and high stiffness values.
20-millimetre thru axle
20 mm thru axles can be found in bikes with 160 mm travel and upwards. They are slightly stiffer than 15 mm axles, but also heavier. Depending on the model, they are closed via a lever or a hexagon socket.
