12mm Thru Axle for Kid Trailer

(25 customer reviews)

$ 65.00

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

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SKU: KID207 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 229 mm, but can be shorted using the included 12 mm spacer for a 217 mm axle. 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 12×197 hub does not equal a 197 mm 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?

25 reviews for 12mm Thru Axle for Kid Trailer

  1. George (verified owner)

    What can I say, this is the kind of thing that either works or doesn’t. I’ve been using it for a few weeks now on road and off with a double trailer holding two little ones weighing about 55lb attached to a 907 Fat Bike. No problems at all.

    I’ll actually be ordering another one for my wife’s bike soon – the cost is worth the convenience and it lowers the risk of damaging and the wear and tear on the bike threads.

    And finally, shipping. This axle arrived at my Alaskan address in three days. Anyone that’s lived here knows that’s super fast. That means the moment they got the order, it was packed, labeled and out the door in the first thing smoking – priority!

  2. James VanBeynen (verified owner)

    Fast shipping, easy to install, and perfect fit for my bike. Used the trailer for over 30 miles now and no problems.

  3. Jacinthe Bourdon (verified owner)

    Perfect! I was really unsure when I ordered the axle since I know nothing about bike mechanics! I needed to pull my chariot kids carrier with a fat bike to continue to bring the kids at daycare by bike even during the winter months. It works perfectly, the design and constructions are very professional. When the roads are clear with a little bit of snow, I can easily pull my two kids weighing about 75 pounds together. And this is so much fun, way better then the car. I highly recommend this product. Really fast shipping.

  4. Richard (verified owner)

    Excellent product. Fits straight onto my Haibike fat bike so I can attach a pet trailer. Easy to install – good instructions and video available online.
    Fast shipping to my overseas address here in England.

  5. Ben (verified owner)

    So glad this is something that exists!! The guide for selecting the correct axle was super easy to use. The axle arrived quickly and installed easily. I’ve taken the kids for a few rides and it works flawlessly. I’ve checked the torque on both the axle and the hitch mount after riding and it appears good to go. I know it would be more expensive, but I do wish there was some sort of quick-release version. I’m not looking forward to removing the axle if I have to change the tire or do any other maintenance where removing the back wheel is necessary. I mean, it’s not that difficult to install this axle, but it’s certainly more time consuming than a quick-release.

  6. René Chabot (verified owner)

    Excellent service! I had to email a few times for questions and responses were always professional and timely. As for the product, easy instructions, easy assembly and works flawlessly. Worry free! Thank you.

  7. Patrick

    Fits perfectly, great solution, I’m thinking about getting one for my mountain bike!

  8. Erik G.

    This place has amazing customer service. Their product knowledge has surpassed anybody else on this topic, including manufacturers and retailers. I purchased this axle and then, unprompted, was contacted to let me know I had purchased the wrong axle. This was after bringing my laptop to the bike shop to look up specs. I didn’t end up needing the axle, which saved me $75. I will be back because I plan to use my kid trailer on multiple bikes, some with thru axles. I will also recommend the Robert Axle Project to everyone I know dealing with compatibility issues. Great company!

    • Katy

      Thank you, Eric. We are chuckling at the comment about how manufacturers or retailers can’t even figure out what axle goes with what bike. We try our best to make sure our customers get the right product!

  9. Ben S. (verified owner)

    I’m so glad this is now possible for fatbikes. My kids don’t ride in the chariot any more, so I use it for hauling gear on our bike camping trips. Everything was solid. The only problem I had was with the installation on my fatback rhino. It seemed that it was in between sizes. No problems though, I just hack sawed the spacer in half and filed it down. Now if fits perfectly and works great!

  10. David Wiskochil (verified owner)

    Put simply, this axle is perfect. Although I purchased it to enable towing my burley trailer, I have found the axle to be stiffer than the OEM unit it replaced.

    The installation was a breeze, the packaging simple, and the instructions easy to follow.

    I have already recommended Robert Axle products to my friends, and will continue to do so.

    Thanks for a great product!

  11. YTfatDad (verified owner)

    The product was easy to size up using the axle chart. Shipment notification was quick, so was delivery was pretty good to northern Canada. Product is doing the job and all is good.

  12. Jonathan (verified owner)

    Wow.i cant believe that I received it yesterday and it went in beautifully. Thanks for making a truly great aftermarket part. I will spread the word

  13. Jon G. (verified owner)

    I just recently purchased a 12mm axle for my Fat bike so I could hook up my trailer to it. I placed the order on a Friday and the axle was in my mailbox Monday! Is that fast or what? Installation was a breeze. Now my grandson and I bike around like we were meant to. Thanks for providing a great aftermarket axle that solved my problem.

  14. Jordan (verified owner)

    ordered one for my ‘18 trek Farley. No need to measure as it was easily chosen through drop menus.
    High quality, nicely machined part!

  15. Will Smith (verified owner)

    I received my fat bike axle about a week after ordering it. It was exactly as described and fit perfectly. Thanks Robert Axle Project!

  16. Frank D (verified owner)

    Works perfectly for my Trek Farley 9.6 & Thule Chariot Cross. Same great quality as my other Robert Axle.

  17. Andy (verified owner)

    This is the third axle I’ve purchased for my bikes from Robert Axle Project. I have one on my Jet 9, and two for my Growler Fatbike. One is for regular riding and now a trailer axle. These axles are the real deal. Easy to measure/determine for your bike, light, very stiff, and have a great finished feel to them.
    The trailer axle, in particular, is well-made, and easy to figure out how to attach to both the bike and the trailer hitch. I would recommend anyone looking for an axle, whether for a trailer or just to go stealth, seriously consider Robert Axle Project axles.

  18. Mark Ostlund

    This company is great. They are very responsive and have a critical product for newer bikes with thru-axles. And if you make a mistake and order the wrong axle like I did they will make it right. Highly recommended. 🙂

  19. Caitlin (verified owner)

    Great product and works well for our bike set up. Took two tries to get the right size but it’s perfect now 😊

  20. Nancy (verified owner)

    Everything about your site and product is beyond 5 stars! I needed a new axle for my Fatback bike to pull a Burley Flatbed Utility Cargo Trailer. There isn’t a bike shop within 400 miles of where I live so I was thrilled to find The Robert Axle Project. All the information was clear and easy to follow on line. Once I had my axle in hand the information that came with the axle made checking the threads and swamping out the axle a breeze. Thank you for your excellent service and product!

  21. Daniel (verified owner)

    Used once so far- however it was easy to install fitment guide was very easy to use, liked the double check feature when checking out. Works well with my Farley 5 and chariot trailer

  22. Ryan (verified owner)

    Always happy with the axels I get from Robert Axel project!!!

  23. Craig E MacDonald (verified owner)

    Fast shipping and worked perfect!

  24. Sean (verified owner)

    Shipping was quick and I’m perfectly satisfied with my axle.

  25. Quinn (verified owner)

    I needed an axle for my fat bike that would work with my Thule chariot. The axle finder pumped out exactly what I needed and it arrived at my door in Canada in less than 24 hours. Unreal!

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