Mountain Bike Quick Release Standards

A guide to mountain bike axle standards.

Mountain bike quick release standards. Skewers use a camming mechanism to secure the wheel to u shaped fork dropouts. Then along came thru axles borrowed from mountain bikes where they. This works on frames with open dropouts only. Quick release skewers are now mostly found on cheaper bikes jonny ashelford immediate media.

Some wheels and forks have swappable end caps or dropout inserts allowing for the use of either. Mountain bike axle standards explained. However the latest generation of bolt through mtb forks and frames utilizes larger diameter axles for additional. Which quick release is right for you.

These were used for many years on mountain bikes using 100mm front and 135mm rear axle spacing i e. Old quick release hubs and 142 x 12mm thru axle hubs have the same widths between the hub flanges so there is no change in terms of hub flange positioning and wheel strength and stiffness. Again the axle is part of the hub. Mountain bikes mostly use a 15x100mm front thru axle and you might still find a few road bikes that adopted that standard early on but 12 100 is more future proof for road.

Both quick release skewers and thru axles are metal rods that keep bicycle wheels in place. The first crop of disc bikes used quick release with 100mm axle length at the front and either 130mm or 135mm at the rear. For most standard road and mtb bikes the wheel hubs will accommodate standard 5mm skewers. As always there are some exceptions but we will focus on modern axle standards that are supported by pub wheels.

The end of the quick release skewer era. The long time standard for rear hubs was 135mm width with a 10mm diameter hollow axle and a 5mm quick release. Thru axles work better to keep wheels attached to the bike. When choosing a quick release the most important things to note are skewer diameter skewer length materials and cam type.

The width from one face of the hub to the other a k a. If it is a thru axle it would have a ta in the description such as 110ta. Thru axles thread through the wheel hub and circular dropout holes. Quick release thru axle.

Traditionally frames and forks had slotted dropouts. In bicycle nomenclature qr refers to a skewer and ta refers to a thru axle.