Surly 12 X 177 MDS Thru-Axle for Kid Trailer

(6 customer reviews)

$ 65.00

This axle is for use with Surly MDS or Gnot Boost axle system with 12×177 hub standard bikes.

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: KID219 Category:


This axle is compatible with Surly bikes that have the MDS or Gnot Boost axle system and 12×177 hub spacing.

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.

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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

Additional information

Weight 0.3125 lbs


Robert Axle for Surly MDS bikes replaces your stock axle to attach your child trailer to your 12×177 hub spacing thru-axle equipped bike.

  • This axles is specifically designed to fit the Surly Wednesday.
  • The derailleur end of our axle is internally threaded and will use the bolt from your stock Surly axle. The disc brake side of our axle has an engineered mount for your trailer hitch. That mount has been permanently attached to the axle.
  • This axle is compatible with Burley, Carry Freedom, Chariot/Thule, Croozer, Instep, and many more.
  • 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?

6 reviews for Surly 12 X 177 MDS Thru-Axle for Kid Trailer

  1. Tero (verified owner)

    This was exactly the thing I needed for my kid trailer to hook up with my Surly Wednesday and it works flawlessly. Not only that but customer service was also excellent!

  2. Dragan (verified owner)

    This is exactly the piece I needed for my fat tire bike to accommodate the child trailer. The axle was recommended by a tech in a bike shop. The trailer’s hitch needed to be separated away from the back wheel so that it can go into the fully horizontal position, and this axle does the job. Couldn’t be happier with the product!

  3. Doss (verified owner)

    High quality part. Fits Surly Wednesday as perfectly as stock axle. Allowed me to bolt the new style Burley hitch on easily. The non-business end of the Axle is internally threaded like your stock Surly axle and uses the stock Surly bolt. 4 stars because the description does not make this clear, and Robert now knows it should…

  4. Nicholas Littlefield (verified owner)

    Best through axel for the Surly Wednesday + Kid Trailer! Couldn’t be happier. Perfectly machined and integrated for the Wednesday. Look no further.

  5. Zane (verified owner)

    Works great on my Surly Wednesday- quick shipping too. Only small complaint is that the search feature on the site doesn’t have the Wednesday in the database from what I can tell- so ensuring that I had the right axle took a bit more digging (thank you other reviewers!) than I though it would.

  6. Mark H. from Michigan

    I ordered this axle for my Surly Wednesday, as well as a more standard 12mm thru axle for my Trek Superfly MTB. I have 4 bikes, but was down to only one that had a rear quick release skewer (the only one that could fit to pull my Thule Chariot bike trailer).

    These axles are a game-changer! Ordering was so easy, you just punch in your bike model, and the site tells you the correct axle to order. Shipping was quick, and they arrived with an easy-to-follow installation guide.

    Now I can use my sturdier bikes for my kid-puller and grocery-getter! 10/10. Will be back to buy more if I get a new bike that needs a different axle size!

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