12mm Thru Axle for Kid Trailer

12mm Thru Axle for Kid Trailer

(94 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.

SKU: KID213 Category:




94 reviews

  1. Doug

    Until I found this product, I was going to purchase a mtb I didn’t really like as much as the Specialized Camber 29er becuase I needed the ability pull my child trailer. This thru axle fit perfectly and felt sturdier than the original.

  2. Far North AK (verified owner)

    Awesome! Works on my Santa Cruz perfectly. Now I can go have fun on the single tracks and come back, put on the trailer and go out with my wife and daughter on the same bike! It rules!!!

  3. Kelly (verified owner)

    Works great! 10+ I can ride with my pup in the trailer any time now, on any bike! (My disc brakes and thru-axle were a challenge previously)

  4. Siso (verified owner)

    Works Great! +1

  5. Steve Fleck (verified owner)

    Great product! Really well made and works perfectly with my mountain bike. No need to bring a separate bike to tow the trailer anymore.

  6. Andrew Fuquay (verified owner)

    The axle fit perfectly on my Santa Cruz blur. Seems to be very strong. I’m able to hook up and disconnect my baby trailer without swapping axles. Just leave the Robert axle in and hit the trails after pulling my kid around town. This is a great solution for the over size thru axle problem for hooking up attachments. I spent a long time trying to figure out a way to hook up a trailer to my mtb’s, I’m super stoked to have finally found something like this. Thank you guys.

  7. Kurt (verified owner)

    This worked great for my bike. Very easy to install and use with a Thule Chariot Cougar. Just be careful to not overtighten, as it could be difficult to remove. I swap back to my stock axle for actual mountain bike rides.

  8. Pierrick (verified owner)

    Je suis super content !!!
    This worked great for my e-bike. It’s easy to install.
    I use it with my crooser chariot.
    Now I can travel with my daughter!!
    A french biker happy

  9. Justen (verified owner)

    I have a stump jumper soft tail that I love to ride but found myself taking my less desired backup bike to pull my youngest around in until I found this axle. It’s awesome I have found it mounts to literally every child trailer I have ever seen. Great product very well made, and shipping was fast. Thank you guys for making a great product.

  10. James (verified owner)

    Ordered this item for my wife’s new bike so she can tow our son to the park in the Burley Honey Bee trailer. Works and fits perfectly for this application with absolutely no issues. So glad I found Robert Axle Project. It saved us from buying a separate bike just to tow our son. Now she can enjoy an awesome bike for trail riding, AND tow our son for leisurely rides on the bike path on the same bike. Great product!

  11. Brett (verified owner)

    Amazing product and the engineering and design is fantastic quality! I ordered the wrong axle and the support team immediately helped me figure out the correct one and shipped it to me the next day. Installation was super easy and pulling my new Bob Trailer was so smooth and easy. Started training with the trailer for my first wilderness trek with a trailer and I have to say that every ride has been so smooth and solid thanks to this product! Well done guys and you have a fan for life!

  12. Alessandro Porrazzini (verified owner)

    Perfect!!! Very good fabric, good seller; fast delivery

  13. Victor Ing (verified owner)

    Glad I found this online and thank you for designing and manufacturing this much needed product!
    I tow my disabled adult son in a large special needs trailer. I now use my electric bike with this hitch mount thru-axle and know that the mount will hold up to the load. With over 80kg in tow, I now feel confident in the strength and quality of this product.
    Thank you!!

  14. Thomas D (verified owner)

    Works like a charm on my 2014 Stevens Jura Mountainbike. My son loves it to get to the Kindergarden by bike with his dad. Thanks for making this possible.

    • Katy

      That’s what we like to hear – biking to kindergarten. Thanks for sharing!

  15. Paul (verified owner)

    Amazing product, fits perfectly on my Santa Cruz 5010. I spent along time researching an axle that would work with my bike and thankfully The Robert Axle Project had one. Shipping was quick, even to Canada. I can now pull my son in his Thule bike trailer and I’m considering just leaving it in at all times so we can pull him whenever we want.

  16. Kristian Skjødt (verified owner)

    Axle is great. I had modifications made to my old trailer bracket but it did involve cosmetic damage to my frame. This one is super easy to mount, it’s very rigid, stays in place, and easy to switch around with other bikes.

  17. Denise and Michael (verified owner)

    The through axle was very easy to install on my Specialized Rumor and my husband’s Specialized Epic. We tow our Border Collie puppy to the park in his Burley Tail Wagon for some extra playtime. Makes for a very happy puppy! Now I have the ability to pull this trailer with every bike I own. Thank you for developing a product that meets our needs!

  18. UK buyer (verified owner)

    Have to say that the customer service from Chris at Robert Axle has been fantastic.

    Really helped out with an issue that I had, and made buying from the UK very easy.


  19. Stephen M. (verified owner)

    Application: 2016 YT Industries Capra pulling a 2016 Burley Bee.

    Website was very easy to navigate through for selecting the correct axle for my bike and trailer. Simply pick your bike and what trailer you’re using and it pops up.

    Installation was very easy and the product is very well made.

  20. JP Lewis (verified owner)

    Whip: 2016 Specialized Turbo Levo FSR – Charriot Cougar 2

    I got a quick reply on the verification of the axel type :: so that was cool.

    This axel is so awesome! We were able to haul our kids up a snowy road and hike into some Hot Pots in the Winter… blew our minds how this simple tool made it all possible to do such a grand trip with our kiddos in tow. Thank you!

  21. Le Corse (verified owner)

    Great product fitting perfectly my Stumpjumper, I received it faster than expected. I will highly recommend this product.

  22. David Sweeting

    Very happy- fits my stumpjumper and just works. Fast delivery as well all the way to NZ, thank you very much guys 🙂

  23. Hill (verified owner)

    Totally seamless fit between a Burley D’Lite and a Specialized. Happy with the entire buying experience and really thankful that the RAP is out there making these axles so that I can keep using my trailer with my new bike.

  24. Drew (verified owner)

    I was worried about it fitting my new bike with the X12 axle so I wrote them to see. Response was really fast and he gave me a link for the exact one to order. Click and ordered. Works fantastic for when I want to pull a kid trailer around the neighborhood on my $7k bike!…

  25. Paul Peterson

    Just installed this after having it delivered from Germany to Sweden!
    Works perfectly! Top notch product.
    Now we can resume the daily dargis (daycare) drop off.
    Except now it’s behind my new specialised turbo Levo, so are doing it in half the time!

  26. Karl (verified owner)

    I was so happy to find y’all’s axles. First time ordering I wasn’t sure I got the right size. The fit guide helped get the right axles for us (one for my wife, one for me). The axles are robust and well designed to fit a range of lengths, so clever. Y’all thought of everything. Five stars for y’all’s customer service too, you responded to my issue so fast and very kindly. My son loves going for rides now, and I am confident he’s safely in tow. Thank you.

  27. Nicholas Citriglia (verified owner)

    Worked on my 2016 Specialized FUSE! Kiddo loved Bar Harbor carriage trails. The axle fit perfectly and arrived super fast! Thanks for making this my family is very appreciative!

  28. Jorge Rodriguez (verified owner)

    This fits my 2012 Stumpjumper FSR perfectly. I would even say better than the original DT Swiss Through Axle. This is a perfect solution for what seemed to be an unsolvable problem; even my LBS told me there was no way to attach a trailer to my bike. Shipping was lightning quick and the support videos are comprehensive with installation instructions; follow the initial installation instructions, and it’s really easy to switch back and forth.The axle is really well made and exceptionally engineered. They’ve done an excellent job at designing such a simple, yet elegant solution.

  29. Tiffany (verified owner)

    My local bike shop recommended this part and it works as advertised. The sizing chart was spot on, installed with easy to follow instructions (I loath returning internet purchases that don’t work). Pulling a Burley kid trailer with a Specialized 29er and as a new parent I’m discovering a whole new world of gadgets. Would love to see your product at bike expos and local bike events — quality axel and user friendly website.

  30. Daniel (verified owner)

    great product that works with my Chariott and nice thing is with the included allow spacer it fits both my wifes Intense that is 142×12 and my boost bike. Know not case in all but this is great that the boost to non-boost spacer is included. Made our day and little one loves it!

  31. Mike (verified owner)

    Very pleasantly surprised how seamlessly this worked with my bike. I had a difficult time finding a thru axle for my mountain bike. But this one slipped right in and my little boy and I were on our way in no time. Very happy with the purchase.

  32. Paul (verified owner)

    Product far better than described and service is just simply first class! Easy to fit and once on its super easy to remove and use the original when not towing.

  33. pukki81

    Using this on my Canyon Spectral al 7ex with great results. Seems actually better than the stock axle that came with my bike. I can just leave it on the bike and use the kids trailer hitch when needed

  34. Ed (verified owner)

    The 12mm thru axle works perfectly on my Stumpjumper. It allows me to pull a Burley cargo trailer with no problems!

  35. Dan

    Works perfectly on my Specialized Epic. Great job guys!

  36. Doggie Traveller (verified owner)

    great product, easy to identify correct axle and fast delivery

  37. Hunter (verified owner)

    High quality product, easy to identify correct axle, quick support for any questions, and fast delivery.

    Awesome to be able to pull a trailer with a Specialized Turbo pedal assist bike!

  38. Miikka Nevalainen (verified owner)

    Perfect solution!

  39. A A Ron (verified owner)

    Solid product. I just like every other reviewer of this product found, purchased, and received everything I expected with this through axle. Quality craftsmanship, and the perfect component to allow me to enjoy time with my wife and children. (and six stuffed animals, and snacks, and wa wa, and a ba ba)
    Well done Robert Axle Project.

  40. Derek H (verified owner)

    Thank you for sending the axle quickly which arrived with good instructions and well packed. The axle is perfect for the trailer that tow behind my e-bike.

    Thank you again,


  41. Tim (verified owner)

    So happy to have found this resource. Super easy to indentify the correct axle and fast shipping. The product works perfectly.

  42. Angel (verified owner)

    It is an excellent quality shaft, it is perfect for my bike, Specilized Turbo Levo. The shipment was fast, I live in Spain. I definitely recommend it.

  43. Tom Lindsay (verified owner)

    Perfect fit, high-quality product with amazing post-purchase support!

  44. Tyler (verified owner)

    Purchased for my Specialized Fuse Comp 2018. Quick and easy install, works great with my Burly Bee. Axle is well made and instills confidence when you can compare it to the bikes existing axle. I have zero complaints and zero worries that I’d have any issues with this axle.

  45. Stian Rølvåg (verified owner)

    Bought this for mye Specialized Turbo Vado 3.0. It fits very well. Awesome product and delivery time.

  46. Jason in Arizona (verified owner)

    This is was a lucky find and an excellent piece of hardware. I haven’t bought a new bike in nearly fifteen years so the through-axle was something I had only seen on downhill bikes and was bummed when I realized my hand-me-down kid trailer wouldn’t attach. This is the missing piece we needed. It works well and feels super stable on my Specialized Sequoia.

  47. Michael Davies (verified owner)

    Fits great, easy to install (hold the axle with the allen while you tighten on the trailer yoke). Allows me to bring one bike on bike trips which is sweet because it is my only trick to get the baby to nap.

  48. Rodney Bosson

    Works fine – no problems fitting the axle – The trailer fits and have traveled over 200 miles since installing it three weeks ago. Can not speak highly enough of the service and the product. Fully recommend.

  49. Peter Henriksen (verified owner)

    Great product, very well made and fits perfectly. Excellent communication and very efficient service, it was delivered to me in NZ in less than 4 days!

  50. Maxime B (verified owner)

    Fonctionne vraiment très bien. Je recommande sans hésitation. Je trouve que tirer le chariot des enfants est beaucoup plus facile et stable avec le vélo de montagne que le vélo de route.

    It is perfect. Working really great with my MTB 12×144.
    I find it way more stable and easier to pedal the kid trailer with the MTB than the roadbike. I highly recommend the Robert Axle.

  51. Lukasz

    Superb! Better than original one! Fast shipping, recomend to everyone.

  52. Brandon Copley (verified owner)

    This solves my thru axle problems with my InStep Single Seat and Double Seat Foldable Tow Behind Bike Trailers. I can now run this trailer behind my carbon gravel bike without worrying about the frame. Love it!

  53. Gabriel (verified owner)

    Fits and works!
    Shipping overseas worked perfectly too.

  54. Kerry Anne Godbout (verified owner)

    Oh man! This axel SAVED our summer! I ride a Spec Chisel 29’er with a maxel and I was having a heck of a time finding the right axel to tow our Thule trailer. The axel finding feature on this site got it right, the shipping was fast, and the axel is a beautiful fit. I even forgot to take it off on a solo ride and it survived the pounding like a champ. Made a customer for life!!

  55. Vera Krsickova (verified owner)

    Great product, works perfectly with my eBike. Very fast oversees shipping. Thank you. Vera

  56. kip smith (verified owner)

    Exceeded my expectations.
    Easy to install & use.
    Love it !

  57. Petter Hartmann (verified owner)

    Good product, good price and fast delivery even to Norway. Thanks

  58. Tarah Vernon

    This is a game changer! I bought a Hamax outback and could not get it to work on my Giant Trance for months I searched….until Robert Axle Project. It was so easy to figure out what I needed and it has worked perfectly!!! Thank you!!!

  59. Dan (verified owner)

    Bought this axle after moving from a bike with QR rear to a new boost TA. Needed to pull my kids in the trailer with the new bike, and this is exactly the solution I was looking for. Feels much more solid than the previous configuration. Super high-quality construction, install/fit was flawless.

  60. Rod (verified owner)

    A well-made product at a fair price with excellent, fast customer service. I purchased an axle from this company because the alternative was to have one custom-made at a considerably greater cost and with a much lower grade of finish.

  61. Dustin (verified owner)

    High quality axle and allows my Burley Tail Wagon to fit onto my Specialized Turbo Vado. Can’t say enough, about the quality of the product.

  62. Dan Wrobel (verified owner)

    Works perfectly on my Specialized Turbo Levo pulling a Burley d’lite

  63. Vincent Tolete (verified owner)

    A year ago I stumble on this product via Facebook but I couldn’t find a axle for my DH specialized big hit 2 FSR. When I got the chance to have Cube Reaction TM Pro 2019 then time to have one, the ease of not removing the axle just to hook up the trailer hitch is absolutely amassing. Now I can ride my bike on the trials and if the kids wants to be on the chariot its easy hooking it up.

  64. Raymond Stone (verified owner)

    So far it’s a great purchase. Easy to install on my MTB and now my son enjoys traveling with dad.

  65. Nick Psaros (verified owner)

    I was a bit skeptical at first since I didnt know what to expect but I was happy to see that the axle is made with care and feels of quality. it fit perfectly in my Levo Turbo and gave me the ability to take my son with me on rides. I am very thankful for that.

  66. John & K9 Cali (verified owner)

    So easy. So good. So fast.

  67. Lauri Hiltunen (verified owner)

    Axle was perfect for my Canyon!

  68. Leslie Osborne (verified owner)

    Works perfectly. Easy to install.

  69. Laurence (verified owner)

    So happy i happened to stumble across this when i bought my trailer to pull my kiddo. Like many others my hyrdraulic rear setup was not gonna work with the trailer connection. Happened uppon this axle googling and rest is history. Do 10 miles a day 4 to 5 times a week and could not be happier. The machine work is top notch and fitting to my stump jumper is perfect

  70. Darren (verified owner)

    Great product, pumped it worked so easily.

  71. Patrick Snow (verified owner)

    My friends and I ordered for our Chariots. I installed on a Topstone, Diverge, and a Crux. Quality product. Quite impressed.

  72. Johan

    Works well on my 2019 stumpjumper carbon.

    Thumbs up for a great product.

  73. Shawn (verified owner)

    Works perfect for my 2018 Stumpjumper Comp 29! Thanks for making such a great product!

  74. Patrick (verified owner)

    Perfect solution for pulling our small dog trailer behind my E-bike. Easy to install and high quality.

  75. Josh Nix (verified owner)

    Exactly what I was looking for

  76. Steve (verified owner)

    Easy to select proper axle. Delivery was fast. Really nice axle, great workmanship, easy install. What more could you want?

  77. Roald D (verified owner)

    Fits perfectly to my Specialized turbo Levo HT with thule chariot KID trailer. Excellent product and fast delivery to Norway.

  78. Matt Martinez (verified owner)

    Exactly as described. The thru axle is working well on my Specialized Levo SL to pull my daughter’s trailer. Build quality is great. Very happy with my purchase.

  79. Andi (verified owner)

    I was so excited to find out about this product from a friend! Like other reviewers, we had also just about given up on trying to take the kids out using my Specialized bike and were going to give in on only taking them out with an older bike we owned, but then found out that there was a way to make it work. Super easy to install and superior quality, couldn’t ask for more! I definitely recommend Robert Axel Project to anyone who loves cycling.

  80. Arnaud (verified owner)

    I have been looking for months for a solution to attach my favorite Thule trailer to my favorite SCOTT e-bike. No local bike shop could help. This axle is very smart, easy to install, very solid. Quick delivery in Europe (Switzerland). I am very satisfied and I highly recommend this product.

  81. Glenn

    I bought two of these for our two 2020 Specialized Turbo Vado e-bikes so we can pull a Burley D’Lite kids trailer behind either e-bike. The axles worked very well and I did my first trailer pull last week. The only issue is with the Turbo Vado”s, as the kickstand is situated a little far from the frame, so I had to use the provided spacer/washer to push the Burley Steel Adapter out a bit. My only reservation is that the locknut only threads onto the axle about half way. If the outer bolt were bout 1/8″ to 1/4″ longer, I think the Burley steel adapter would be more secure? It works, but that little extra length for the Vado’s would be better.

  82. Kevin King

    Perfect! Works as advertised

  83. Johan (verified owner)

    Works well on my specialized Roubaix for hauling the Thule kid trailer. Even being a Swede and Thule being Swedish it was too difficult to figure out which axle from Thule fitted my bike (if any..) so RAP solves it with their easy guide.

  84. Spencer (verified owner)

    Exactly what I needed to pull a kid’s trailer with my specialized ebike. Easy install. I’ve already put about 30-50 miles on it.

  85. Todd (verified owner)

    Works perfect on my new Scott Spark. So easy to take on and off! Thanks to you all, I didn’t have to buy another bike just to pull my kids in their Thule!

  86. Jimmy Gillespie (verified owner)

    Worked excellent with my Specialized Turbo Vado 4.0. Hooked up a bike trailer to it (it’s electric) and pulled my two kids very easily! This axle has been perfect so far.

  87. Mike Hughes (verified owner)

    Super easy website to find the right axle. Fast shipping (to Ireland) and the product works flawlessly! Thanks guys!!

  88. Robert (verified owner)

    Works perfectly for my pet trailer. High quality. Now I can train without leaving the dog at home!

  89. Lance Gamero (verified owner)

    As advertised. I have a Specialized Stumpjumper (2018) and the axle has work great so far. Great product!

  90. Daniel (verified owner)

    Absolutely great, i wish i have found this site earlier. I wish I had found the site sooner. Thanks Thule for the hint. I was already desperate.

  91. Mike Fisher (verified owner)

    Works great on my Specialized Turbo Levo!

  92. Ben (verified owner)

    Purchased for use with my gravel bike and Burley trailer, works great!

  93. Todd C (verified owner)

    Excellent product, excellent service! Fast shipping! We’ll be ordering another one for my wife’s bike!

  94. Myles (verified owner)

    Well machined, easy to figure out what I needed with the online wizard.

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All orders from our website are via US Postal Service, from Oregon, U.S.A. We make every effort to ship your order within one business day.

Shipping rates and average delivery times are:

• United States: $7.50 USD, 3-4 business days

• Canada: $21.50 USD, 10-14 business days

• All other International: $21.50 USD, 12-16 business days

We are unable to offer expedited shipping. If you need expedited shipping of our products, please visit our Dealers & Distributors page for options. We cannot take responsibility for any delays during shipping, including delays in customs or incorrect shipping information.

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