12mm Thru Axle for Kid Trailer

(48 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

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SKU: KID211 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 180 mm, but can be shorted using the included 6 mm spacer for lengths of 174 mm or 180 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 12×148 hub does not equal a 148 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?

48 reviews for 12mm Thru Axle for Kid Trailer

  1. Aaron Drexler (verified owner)

    I had a problem (not being able to use my new bike trailer) and the Robert Axle Project 12mm thru axle for kid’s trailer was the perfect solution! I have now put this thing to the test on several rides with my son and it’s held up extremely well. You know something’s good when you can just forget about it.

  2. Anthony (verified owner)

    Works great, and only took a few minutes to install. Very pleased with the purchase.

  3. AJ (verified owner)

    The Thule brand adapter wouldn’t work for me so I reached out. The Robert axle works perfect and shipped quickly. Thank you very much.

  4. Jakob Peterson (verified owner)

    Works great on my bike. Received very quickly. Was shipped the same day I ordered it.

  5. Zak (verified owner)

    Works perfectly, easy install, very well made, and received quickly.

  6. Brian (verified owner)

    This worked perfectly for my Niner RLT 9 hooked to a Giant kid trailer! I pulled my four year old along on his first bikepacking adventure. An over-nighter to a Michigan state park campground. 35 mile round trip and no issues whatsoever (other than a few potty emergencies and cries of “are we there yet” from the back). Looking forward to our next adventure!

  7. Kristian Knudsen (verified owner)

    Easy to install and it works great. I was a little worried that it wouldnt be strong enough for the trailer. But after heavy use for about a month its going on strong.

  8. Ben (verified owner)

    Easy to find the axle you need. Easy to order it. They even sent it to New Zealand. Nothing I can think of could have been done better.

  9. Mike BILYNSKY (verified owner)

    Best thing ever! Great quality construction and drop in fit.

  10. Paul Standing (verified owner)

    So I use my new Norco Torrent (with thru axles) hauling a trailer as a side gig delivering just under 100 daily papers around the neighbourhood.
    I love the job and my new “Robert Axle” is just the ticket required. I no longer think about the approximately 75 lbs I’m hauling and how it may effect both my cargo trailer or my axle. It just works.

  11. Heather (verified owner)

    Glad to be back on the bike and a new version of freedom!

  12. Steve (verified owner)

    Perfect! Allowed me to hook my pet trailer up to my 2017 Haibike Sduro. Now I use it for all kinds of things- trip to the hardware store? No prob. Groceries? Yup. Nice work.

  13. Ethan (verified owner)

    Took no time at all to find the correct Axle for trailer which mount. I have a Fuji and a Trek Bikes needed ban axle for each so I could use my trailer for grocery hauling or camping. They have the perfect axle for each bike. they made it easy and quick to get what I needed. Only took a few minutes to change out my axles. Wish buying parts was this easy all the time.

  14. Jonas (verified owner)

    Passer perfekt på min Haibike. God kvalitet. Kjapp levering.
    Perfect for my Haibike. Good quality. Fast delivery(to Norway).

  15. Bennett G (verified owner)

    Works perfectly. I am able to pull our chariot trailer with my TA bike. The axle finder is a good tool. Overall a great product at a reasonable price.

  16. Richard Blankenship (verified owner)

    As with all thru axles I have purchased for use with my Trek Domane, they have all been and worked excellently. This thru axle was no exception. Very pleased with the quality of the product and the service from the group.

  17. DB

    Shipped fast. Fit perfect. Keeps that trailer rolling.

  18. Brycen Rackham (verified owner)

    I was kind of skeptical at first, especially for almost $60. However I am very satisfied with the quality and it works like a charm!

  19. AA (verified owner)

    Got what I paid for.

  20. Nicholas Ludwig (verified owner)

    Needed something that would hook a burly bee up to my salsa. This axle works great so far.

  21. Jeremy (verified owner)

    Works exactly as expected and seems like a quality product. No hassles replacing my existing axle and mounting the chariot hitch. Delivery was also quicker than expected.

  22. Jacob Loehr (verified owner)

    Awesome product. I purchased a kona bike and a trailer to haul my 15 month old around in but I didn’t realize that the trailer wouldn’t hook up to the bike. A guy that works for life cycle bikes in Eugene where I got my bike told me about the Robert axle project and that they could help
    Me out. I sent an email in and they responded very quickly and got me exactly what I needed. The service was great and the product was second to none the machining and quality blew me away. Super easy parts swap out, took maybe 5 min. And now we ride daily. Would highly recommend this to anyone, and I have to a bunch of people already.

  23. Audun Føyen (verified owner)

    Easy to find right axle, very good explanations on the website. Good instructions included. Shipped very quickly! Got it to Norway in a matter of days. Solid craftsmanship. Brilliant! Highly recommended!

  24. Sean Farrell (verified owner)

    This is a phenomenal product! I am finally able to pull my daughter’s trailer with my 2020 Salsa Timberjack. The tool for product for checking was easy to use and gave me confidence that I was buying the right axle. The fit and finish is terrific, and it has brought hours upon hours of joy to my family. Thank you!

  25. Matt Demers (verified owner)

    Fantastic product. I was told about these axles by a local bike expert as I couldn’t hook our chariot trailer to my Kona. The product is really well made and arrived quickly to Canada. Install was five minutes. Thanks for making good products and having excellent service.

  26. Cole (verified owner)

    Five Stars, one for each: works great, fair price, easy install, quick shipping, product for my bike/trailer combo.

    Works great and the quality makes me feel comfortable when pulling the kids around. A huge variety of parts ensures that you’ll be able to find what you need for your bike/trailer combo (which can’t be said about the other big names out there!).

    Thanks for looking after us and keeping us rolling!

  27. Betsy MacInnes (verified owner)

    Needed this axle for Trek ALR gravel bikes used to tow a Thule baby trailer. Could not find this axle adapter anywhere locally. Robert Axle’s website directed me immediately to the correct axle, and they had it in stock, it was an easy installation, and it fit perfectly!! My biggest rave is the customer service I received. They called my on the phone to answer questions I had, put the axle in the mail immediately, confirmed shipping, and I received it two days later. Their prompt service saved a planned expedition out with the new trailer.

  28. Luke (verified owner)

    Exactly as expected with excellent quality.

  29. Ogrum (verified owner)

    Very nice quality axle!

    But more importantly the customer service was very quick and helpful. I had measured my axle wrong (basing it off of the bike specs, which wasn’t the right measurement). I used the axle finder thing and confirmed with the Q&A. Worked out great and found the right one.

  30. Craig Levang (verified owner)

    Fit perfectly, fast shipping, just gave my grandson a ride in the Burley with it.

  31. Amanda (verified owner)

    We got a couple of Diamondback electric bikes so that we could pull a bike trailer with the kids. But then we found we had a thru axle and couldn’t attach the trailer. I stumbled upon the Robert Axle Project, followed the directions for determining size, and ordered. It is perfect! We are so glad that we tried this out.

  32. John F (verified owner)

    Perfect fit and quality manufacturing. Very pleased with the axle.

  33. Micah (verified owner)

    This is a quality axle that works great! We’re very satisfied with it. This company is great with awesome customer service – with my order I asked them to include a drawing of a dinosaur riding a bicycle, and the CEO drew the cutest dino on a bike! I was so excited to open my package and see the drawing!

  34. Greg Y (verified owner)

    Quick and easy to find the right axle, to ship to Canada and to install. The online process was straightforward. Originally bought a wrong axle from Thule for the Chariot bike trailer, and their customer service pointed me this way, and experience was great. Would recommend this product.

  35. TOM LOMAX (verified owner)

    We got this axle for a 2017 Norco Sight C71 and a Burley Honey Bee trailer. Worked perfectly as described and was able to pick up in Bend. Thanks for a great product.

  36. Roberto (verified owner)

    It was the perfect match thanks!

  37. Carey (verified owner)

    Bought the trailer axle for our dog, Isabella, who likes to adventure. We plan to cycle the West Coast from Seattle to San Diego later this year. She’s getting comfortable in her Burley Trailer on short 10-20 miles trial rides. The axle does the job just as described on my Salsa Fargo I’ll be riding.

  38. Mac McCorkle (verified owner)

    Great service. Helped me order the right axle and worked great.

    Thank you for your help.


  39. Sam

    Perfect. Exactly what I needed. Seems very durable. Will be back for any special axle needs.

  40. Israel Ramirez

    Worked fine on my 2021 Fezzari Abajo Peak. Bike was not listed on their website, but removing the old axle and getting the measurements did the trick. Pricey for a bolt, given the expense of the bike plus the child trailer to find out you need another $60 part to make it all work. Overall satisfied.

  41. armando (verified owner)

    perfect fit and made attaching the trailer so much easier!

  42. Tom Saletta (verified owner)

    I didn’t think there would be a way to attach my trailer to my e-bike. Robert Axle Project had the exact product to fit my needs. The axle I purchased was received timely, had excellent instructions on both which axle to purchase and then on how to install and the axle is very high quality. Very satisfied and would highly recommend.

  43. Vinnie Quek (verified owner)

    Had an issue installing the hitch on my new earth+kin wagon to my Jones space frame bike and the Robert Axle Project 12mm thru axle for kid’s trailer solved the problem for me!
    I’ve now done several rides with the wagon with load on and it’s held up very well. And surprised at how easy it was to replace the axle. Very happy customer from Singapore and will sure get more axles for other bikes!

  44. Vinnie Quek (verified owner)

    Had an issue installing the hitch on my new earth+kin wagon to my Jones space frame bike and the Robert Axle Project 12mm thru axle for kid’s trailer solved the problem for me! I’ve now done several rides with the wagon with load on and it’s held up very well. And surprised at how easy it was to replace the axle. Very happy customer from Singapore !

  45. Jim Voth (verified owner)

    Delivery was fast and the product was exactly as ordered. Fitted perfectly on our e-bike and we are now able to reconnect the pet trailer. Well done! I would order these products again.

  46. Nick (verified owner)

    Awesome product and a perfect fit. I wasn’t sure about the fit so asked a question about it and they got back to me overnight, great service. Machining is lovely and works great towing our trailer.

  47. Pauli (verified owner)

    Ordering and size confirmation made easy. Rather fast delivery to Finland. Axel fitted just like it should. I was satisfied, couldn`t think any complaints.

  48. Heidi S (verified owner)

    Great axle, loved the website setup which selected the correct axle for me and it works great with my lil cargo trailer attached to my MTB for in town errands

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