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How-to: Thru-Axle Adapters

How-to: Thru-Axle Adapters

As bikes evolve, so must the bike rack. Initially designed to carry bikes that used quick release wheels (9mm x 100mm), the fork mounted rack was compatible with nearly every bike on the market when it was first launched. While this remained true for a while, an early 2000’s innovation in mountain bikes led to the invention of the thru-axle adapter:

This device allowed new bikes with thru-axles to work with fork mounted racks that were already in production. These are widely known as thru-axle or fork adapters and are great options for adapting racks, both new and old, to work with almost any type of front axle.

Got a fork mount bike rack? Grab your bike and let’s find out if you need an adapter:

1. If your front wheel is secured using a quick release skewer (see example below), you will not need an adapter.

2. If your front wheel is secured using a thru-axle (see examples below), and your bike rack is only designed to work with quick release forks, you will need an adapter (proceed to step three).

3. Remove your front wheel and measure the diameter of your thru-axle. You should get a measurement that's close to 12mm, 15mm, or 20mm.

4. Measure the fork spacing. You should get a measurement that’s close to 100mm or 110mm.

5. Choose the corresponding adapter and you’re good to go!

Yakima 12mm x 100mm15mm x 100mm15mm x 110mm

Thule 12mm x 100mm15mm x 100mm15mm x 110mm

Note that these are the current product offerings from Thule and Yakima. If you have a different size thru-axle or fork spacing, you may need to hunt down a discontinued adapter or find a third party supplier. Some other common sizes include: 20mm, 24mm, 25mm, Lefty, and various fatbike sizes.

Now that you have the parts you need, you’re ready to mount your bike.

1. With the bike resting on the saddle and handlebars, begin by removing the front wheel and installing the adapter. Insert the adapter into your fork and reinstall your thru-axle.

2. With the adapter installed, you can now mount the bike per your rack’s instructions and you’re ready to roll.

Note that it’s normal for your bike to settle in a slightly more forward position.

One last thing to consider when using a fork mounted bike rack. Your bike is secured to the roof, but what about the front wheel you had to remove? While it’s always an option to toss it in the trunk, a wheel holder from Yakima or Thule is a nice way to keep the mud on the outside of your vehicle. Remember your bikes thru-axle may be busy holding the rest of your bike in place so be sure to grab one of these to pair with the wheel holder if necessary.

Need some clarification? Feel free to contact us with any questions!