Mountain Bike Thru Axle Sizes

Ensure your rear hub is the correct size to fit your frame.

Mountain bike thru axle sizes.

A guide to mountain bike axle standards 1. Thru axles make the bike stiffer which reduces lateral flex and results in better tracking especially through corners and at speed. 142 x 12 thru axles are all the rage now. Boost gives a 148 x 12mm spacing which allows for the hub flanges to be further apart which gives a potentially stronger and stiffer rear wheel.

They essentially operate the same as front thru axles on the rear of the bike. Boost being newer isn t as much as a clusterfuck. Plus there are additional lengths for split pivot bikes and trek boost abp. 15 x 100mm 127 length 1 5.

180mm length 20mm thread length. When mountain bikes first went to thru axles the standard was 12 142 which was the same effective width as the quick release hubs they replaced. Thru axles are commonly 12mm 15mm and 20mm in diameter. Thru axles are also inserted through a hollow hub axle but they re bigger rear ones are 12mm in.

15x100mm 15x110mm boost and 20x110mm the first number refers to the axle diameter while the second refers to the dropout width of the bike. 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. In this example 15mm is the diameter 100mm is the o l d 127mm is the overall length and 1 5mm is the thread pitch. You can see more details about these measurements below.

Determine if your frame fork uses a thru axle ta or skewer qr. Traditionally frames and forks had slotted dropouts. Cysky bike axle quick release skewer front rear bicycle axle wheel hub fit for road bike mountain bike mtb bmx 1 pair 3 9 out of 5 stars 325 11 99 11. Front mtb thru axles currently use three standards.

Skewers are almost always 5mm in diameter. Most thru axles are described by four measurements and you might see them described something like this. The hub axle which was 9mm in diameter. Early cyclocross bikes borrowed the 15mm front thru axle diameter but as disc brakes became more common on drop bar bikes they all standardized to 12mm.

The standard mtb rear axle dimensions are 135x5mm for a qr rear hub but jump and gravity bikes may use wider and thick axles for extra strength and stiffness with the available sizes being 135 10 142 12 150 12 157 12 and 165 12. Rear thru axle from my evil following uses a 12 x 142mm m12 x 1 5mm thread pitch shimano e thru standard. Thru axle hub ta skewer hub qr step 2. The diameter of the thru axle there are two common sizes.