Mountain Bike Thru Axle Sizes

Determine if your frame fork uses a thru axle ta or skewer qr.

Mountain bike thru axle sizes.

Boost being newer isn t as much as a clusterfuck. 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. 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. 15x100mm 15x110mm boost and 20x110mm the first number refers to the axle diameter while the second refers to the dropout width of the bike.

Thru axles are also inserted through a hollow hub axle but they re bigger rear ones are 12mm in. Using a tape measure measure inside width of frame fork where hub contacts frame fork. Thru axle hub ta skewer hub qr step 2. You can see more details about these measurements below.

Skewers are almost always 5mm in diameter. 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. Thru axles make the bike stiffer which reduces lateral flex and results in better tracking especially through corners and at speed. Rear thru axle from my evil following uses a 12 x 142mm m12 x 1 5mm thread pitch shimano e thru standard.

Spacing on these is 142mm wide with an axle diameter of 12mm. The diameter of the thru axle there are two common sizes. This is done via visual reference. Most thru axles are described by four measurements and you might see them described something like this.

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. 142 x 12 thru axles are all the rage now. 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. 180mm length 20mm thread length.

15 x 100mm 127 length 1 5. A guide to mountain bike axle standards 1. Front mtb thru axles currently use three standards. Ensure your rear hub is the correct size to fit your frame.

They essentially operate the same as front thru axles on the rear of the bike. The hub axle which was 9mm in diameter. Thru axles are commonly 12mm 15mm and 20mm in diameter. Traditionally frames and forks had slotted dropouts.