12mm Thru Axle for Kid Trailer

(34 customer reviews)

$ 58.00

Robert Axles for Kid Trailers are designed specifically to fit your 12mm thru-axle bike and allow attachment of any hitch-mounted trailer. These fit any trailer that has two wheels and a single point of attachment to the axle. This includes all the two-wheeled child, pet and cargo trailers such as: Thule, Chariot, Burley, Instep, Carry Freedom, and many more.

Purchase our Kid Trailer axle for your bike. Share your stoke for cycling with your kids. Simplify your life by allowing quick and secure attachment of your trailer to your best and favorite bike. Enjoy the adventure.

In stock

Get 20% Off Lightning Bolt-on Axles With Purchase of Any Trailer or Trainer Axle! Discount Automatically Applied.
SKU: KID221 Category:


Since 2013, we have been an important part of cyclists’ adventures all over the world. Our axles have millions of miles on them in mountain bikes and road bikes, carbon bikes, fat bikes and e-bikes. Our axles are specifically designed to handle the high-torque loads generated by e-bikes.

Your stock thru-axle is not strong enough to haul your precious cargo! Our axles are 3 to 4 times stronger than the stock axle that came with your bike. Our stainless steel axle ends provide a safe and secure attachment point of the hitch to the axle. The axle is quick to install and remove with a common 5mm hex key.

Our axles are not just designed in the USA, but are made here as well. They are machined by avid cyclists to the tightest standards in the industry. We safety test, to failure, every batch of axles we produce to ensure they exceed your expectations.

Prop65 Warning icon

WARNING: This product can expose you to chemicals including nickel acetate, which is known to the State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov.


Robert Axle for Kid Trailers replaces your stock thru-axle so you can attach a child or cargo trailer to your 12 mm thru axle equipped bike.

  • This axle is compatible with Burley, Carry Freedom, Chariot/Thule, Croozer, Instep, and many more hitch style trailers.
  • The true length of the axle shaft is 167 mm. Please note: Thru-axle lengths do not equal hub standards. An axle has to be longer than the hub to fit in the frame. A 12×142 hub does not equal a 142mm long axle.
  • This axle has a 1.75 mm thread pitch.
  • The axle shaft and axle end are precision CNC machined.
  • The axle shaft is 7075 aluminum and hard black anodized for rugged durability.
  • The axle end is stainless steel, which allow for mounting of the hitch provided with your trailer. The threads are M10x1 (metric).
  • Hardware for attachment of the hitch is included; the hitch is not.
  • No special tools required. Design allows for installation or wheel removal using your standard 5mm hex wrench.
  • Designed, built and quality tested in the USA. Proven around the world.


Need more information about how our axles work?

34 reviews for 12mm Thru Axle for Kid Trailer

  1. Sam (verified owner)

    I looked forever for the right sized adaptor, with all of the required specifications. This works perfectly. Thanks so much.

  2. Colt (verified owner)

    The print-out sheet is the perfect way to figure out what axle you need, I got the right axle the first time. It looks and fits great.

  3. DMc (verified owner)

    The axle fit perfectly.

  4. Brian

    It works generally well however tightening the trailer to the axle is pretty cumbersome. Especially with the Burley trailer hitch adapter. The recessed nature of the hitch hanger made getting a wrench on the bolt to tighten to the trailer pretty hard. I wish there would be a redesign to get a socket on the bolt while holding the axle still so it’s not overtightened.

  5. Benji Thunell (verified owner)

    Works perfectly!! We have a Thule Cheetah bike trailer and the mount install/axle swap was as easy as it gets! Killer product!

  6. Zach (verified owner)

    Axle looks to be excellent quality and fits perfect on my 2019 Emonda ALR. Burley’s shorter axle was too long (174mm) for my bike and Thule’s axle required spacer’s for the 167mm size. This one is the right size without spacers for a proper fit and cleaner look.

  7. Mick Occhiuto (verified owner)

    Perfect fit! I’m pulling a Schwinn Rascal with my 22lb. pup in tow. It works great and was super easy to install.

  8. J. M. (verified owner)

    Happy with the selection and buying process. Have only used it a couple if times but so far happy with the build quality. I used it on a 2021 Domaine SL7 pulling a Thule Cheetah Chariot Solo.

  9. Phil (verified owner)

    Works as advertised. I use on a TREK gravel bike with a WIKE special needs bike trailer and the fit is perfect. Nice looking workmanship and prompt service.

  10. Michael Wardlaw (verified owner)

    I am very pleased with the quality product. I purchased a 2021 Trek FX Sport Carbon 4 and wanted to use an Upstand (rear hub kickstand) with my bike. I determined I needed to change the thru axle and was directed to Robert Axle for a remedy. Perfect fit! It cost a little more than I expected, but quality matters!

  11. Camillo (verified owner)

    A solid product that fits and works perfectly!

  12. David Nichols (verified owner)

    I just works as advertised! I bought this axle to pull my burley d’lite double behind a Trek Domane. The website made it super simple to get the right size the first time. The axle is well made and ready to roll!

  13. Alain (verified owner)

    Works perfectly for a 2021 Trek Emonda. Very fast shipping, amazing! Thanks RAP.

  14. Diane Venner (verified owner)

    Amazing service. I emailed to make sure I was purchasing the right axle. Someone got right back to me within a day. Then I ordered the axle & had it delivered the next day & I’m in Canada. It fit perfect & I am very happy.
    Thank you for doing a great job.

  15. Tom Chan (verified owner)

    I am so thankful I came across this website. It solved a huge problem for me. I’m so happy I found a way to hook up my kid’s trailer to my Trek road bike.

  16. Ian (verified owner)

    Works perfectly. Initially, I accidentally ordered the wrong axle. Instead of shipping it, someone double checked my bike and contacted me to say I had likely ordered the wrong axle. And they were right. Thanks that person!

  17. Kevin (verified owner)

    Works perfectly to connect my Burley trailer to my 2020 Trek Domane SL6. Well worth the cost.

  18. Tom Christian (verified owner)

    Worked perfectly, I don’t know why Thule hasn’t made their trailers compatible with thru axles but fortunately these guys sorted it

  19. Erwin (verified owner)

    I have a 2021 Norco Search XR A1 (medium size) and this fits perfectly. No spacers required. Been on a dozen rides and the axel holds solid.

  20. Bettina (verified owner)

    I got this adapter and matching spacers to hook our kid trailer up to my e-bike and it works perfectly. The customer service team helped me work out what adapter and spacers I needed, so thanks for stellar customer service and very fast shipping (to Europe)!

  21. Richard Shurley (verified owner)

    This axle worked perfectly on my Catrike 700. I’m pulling my great-granddaughter in her Burley Bee and she is loving every minute of it.
    The axle fit perfectly and is a quality product.

  22. Derrick

    Awesome. I have a few of these – always fit great and are clearly made well.

  23. James (verified owner)

    Spent ages at my bike shop trying to find the right axle only to come to the conclusion that thule didn’t have one to match my bike. Robertaxleproject to the rescue! Super easy to use website, found the right fit and it shipped from US to NZ in less than a week. Legendary!

  24. Glenn (verified owner)

    Fit my bike and trailer perfectly. Shipping was fast. Eazy to know I was getting the right size. Nothing more I could ask for from a bike axle.

  25. Jacob (verified owner)

    I was looking all over and did not understand the full extent of the measurements needed and ended up going to my local Trek store where the employee looked through their system and could not find what I was looking for in their list of stock items. He then turned me towards the Robert Axle Project website and helped me find the correct part for my Domane AL3. The part arrived in a timely manner and matched the estimated delivery date at the time of purchase. The Axle fits perfectly and was very easy to install.

  26. Scott (verified owner)

    Thanks for the rapid shipment and great product. Easy install, axle fits perfectly … so glad you all exist!

  27. Naranja (verified owner)

    It’s rare that I hold such a perfect piece of the machinist’s art. In this case, I got to install it on my tadpole in place of the factory aluminum axle. Aluminum axle, really? It fits perfectly. My compliments on an excellent accessory and the rapid service. Keep up the good work.

  28. Barret (verified owner)

    Honestly I was initially skeptical about using the “find the right axle” tool on the website but I took the plunge and…. it works perfectly. This through axle fits my bike, fits my Burly Nomad trailer, and I have had zero issues. The axle was also shipped and arrived quickly.

  29. Mark (verified owner)

    Perfect fit on Trek Domane SL6, 11 speed cassette. Use this with a Burley Tail Wagen. My puppy (St. Faustina to be exact) has traveled nearly 40 miles already on the trails. What a blessing – the dog and the trailer, and the axle!

  30. Andrew (verified owner)

    This was exactly what I needed to attach a kid trailer to my bike with disc brakes. This was perfect!

  31. Michael (verified owner)

    Pefect fit for my Trek 2023 Checkpoint SL5. Excellent finish and machine work. The fitment guide was spot on.

  32. Troy Crandell (verified owner)

    I’m a pretty handy guy so when my new axel from Rober Axel Project snapped due to a cross threaded nut, RAP sent me a new one no questions asked. The second one fit perfectly and I was able to install it no problem. I can’t say enough good things about RAP, their product and their customer service. Excellent!!

  33. Raphaël (verified owner)

    The axles are the perfect fit (CUBE cross race and TREK Domane 5). It came fast to Germany. I am really happy with the purchase.

  34. Chris (verified owner)

    I couldn’t be happier with the craftsmanship of the product, and the customer service is even better than the craftsmanship. Great product, great people. I worked with Troy and Owen, who got me the right axel for my setup.

Add a review

Your email address will not be published. Required fields are marked *

You may also like…

  • Robert Axle Project Drive Thru 1.75 thread pitch

    Drive Thru 1.75mm Thread Pitch

    $ 35.00
    Add to cart
  • 12mm LIG+no_spacer rear thru axle for bikes

    Lightning Bolt-on Axle – Rear 12 mm x 167 mm x 1.75 Thread

    $ 48.00
    Add to cart
  • TRA+no-spacer trainer axle

    12mm Thru Axle for Trainer: 167mm with 1.75 Thread

    $ 54.00
    Add to cart
  • Robert Axle Project Cycling socks by The Athletic

    Robert Axle Project Socks

    $ 20.00
    Select options