Over-center cam thru axle adjustment and closure

For proper and safe adjustment of a thru axle, read and follow these instructions carefully.

Read the Warning about Mechanical Work before performing any mechanical work on your bicycle.

The over-center cam thru axle system uses a 15mm skewer (Figure 1). The skewer passes through the hub. There is an over-center cam lever on one end of the skewer. The other end of the skewer threads directly into the fork end. With some fork ends, a threaded insert is attached to the fork end.


15mm skewer of thru axle system

Position of the lever

The lever must be in the correct position after it is moved to the CLOSE position. Align the lever so obstacles in the path of the bicycle can not catch the lever (Figure 5). Make sure the lever does not touch a bicycle part or an accessory part (such as rack or fenders), which could prevent the over-center cam from closing fully.

Do not simply rotate the lever to achieve the correct position; adjust the assembly according to the instructions. If you need help, take your bike to your retailer and ask them to show you how to do this.

Some bicycles are equipped with a quick-release lever and a disc brake. If the bicycle is ridden with the lever incorrectly adjusted or open, and the lever contacts the disc or wheel (Figure 7), the front wheel could stop suddenly, causing the rider to fall. Always make sure your wheels are correctly attached, and the attachment mechanisms closed and locked, before riding the bicycle.

To open and close a thru axle

  1. With the thru axle skewer removed from the hub, place the hub ends in the detents (slight indentations) of the fork tips. Make sure all the part are clean. Be careful to center the disc in the disc brake.

  2. Pass the thru axle skewer though the dropouts and hub.
    Different systems require passing from different sides of the bike. You can only insert the skewer from one side.

  3. With the lever in the OPEN position (Figure 2), engage the threads of the thru axle skewer with the other side of the fork and gently turn the lever in a circular motion until the skewer is fully threaded into the fork..
    Note: Do not omit the following steps.

  4. Place the lever in the palm of your hand and throw the lever as shown in Figure 4 to the CLOSE position (Figure 3). At the half-closed position of the lever, there should be some resistance.

  5. Test that you have properly adjusted and closed the thru axle.


Rotate the lever to tighten the threads.
Do not leave lever in OPEN position.


Lever positions: OPEN and CLOSE


Swinging motion of thru axle lever to close


Lever must not interfere with accessories


Lever must not touch fork


Lever caught in disc brake rotor

Adjustment of lever position on Boone and Domane Disc

If the correct adjustment of the clamping force results in an undesirable lever position (See Figure 8, where the lever may contact the fork blade), follow this procedure to change the position. Also refer to the Domane Disc manual.

  1. Loosen the lever attachment screw. (Figure 8).

  2. Pull the lever from the thru axle and rotate (Figure 9).

  3. Rotate the lever position, and reinstall on the thru axle

  4. Check the position, and readjust the clamping force as needed (Figure 10).


Loosen and remove bolt


Rotate lever and reinstall


New lever position. Check function.



To install a wheel

See the instructions to install a wheel with a thru axle.