Use this guide to help you use our Axle Finder.

ATTACHMENT: What do you want the thru axle for?

  • Kid Trailer: A Kid Trailer is child or cargo trailer that has one arm and “hitch” that attaches to the non-drive side of your bike. We fit all brands including Burley, Thule/Chariot, Nordicab, Instep, Trek and Croozer.
  • BOB Trailer: BOB Trailer is a BOB Yak or BOB Ibex, made by BOB Gear. *The BOB Axle does NOT work with “BOB-like” trailers such as the Topeak, Aosom, Burley Coho, or the FatKat Cargo Trailer. Sorry, we do not have a solution for these trailers.
  • Trainer: An “indoor” resistance trainer that doesn’t require you to take the rear wheel off of your bike. We fit every single brand of wheel-on resistance trainers.
  • Wheel Only - Front: Choose if you want a Lightning Bolt-On Axle to replace your stock front axle.
  • Wheel Only - Rear: Choose if you want a Lightning Bolt-On Axle to replace your stock rear axle.
  • Yoke-Mount: A yoke mount trailer is NOT a BOB Trailer, but attaches to the bike on both sides of the wheel. Examples include Surly’s Bill or Ted Trailer and Extrawheel Trailers. Our Yoke-Mount axle can also be rigged for DIY projects such as racks and fenders.


  • City/Commuter Bike: Includes urban or “trekking” bikes with any wheel size.
  • Fat Bike: A fat bike has 3.5 inch sized tires or larger. Not to be confused with a Plus Bike, which is considered to be a mountain bike.
  • Gravel/Cross Bike: A gravel bike, “all roads” bike, “adventure bike” or cyclocross bike typically has drop bars and has tires that are between 30-40+ centimeters in width.
  • Mountain Bike: Any bike, usually with a flat handlebar, with front suspension and maybe rear suspension, and tires that are 2 to 3 inches in width. Some mountain bikes are known as Plus Bikes.
  • Road Bike: Road bikes are designed for use only on pavement and have a tire width of 30mm or less.


Is your bike a pedal-assist electric bike? Choose yes or no.


C’mon, you got this one! It’s probably in big letters on your down tube.

**There’s lots of bike brands out there! If your bike is “Not Listed”, then go ahead and click on “Not Listed” and it will take you to our What Axle Do I Need page for further investigation.


Hub size is the width of your hub from both sides of contact with the frame and the interior diameter. For example, 142x12 (length x interior diameter). If you don’t know the size of your hub, then you might have to do a little research. Here’s how you can figure out your hub size:

  1. Contact the shop where you bought your bike.
  2. Visit the website or contact the manufacturer of your bike.
  3. Measure your hub. Like this:

measure bike hub width

IS IT A...

This is our catchall question to further determine what bike you have and get you the right thru axle. Choose the answer as needed.


If you are still stumped – try taking your thru axle out of your bike and check to see if the dimensions are printed on it. If dimensions are printed on the axle, head on over to our What Axle Do I Need page to find the exact axle for your bike.