Please note that many of the links on our site are affiliate links. These are denoted with an *.  By clicking on them, Rascal Rides gets a small commission on any sale.

Robert Axle Project Review: A Thru-Axle for Bike Trailers

Author: Kristen Bonkoski


It’s a problem that many parents don’t even realize is a problem until the day that they try to attach a bike trailer to their mountain bike or ‘cross bike: most trailer mounts aren’t compatible with thru-axles!

The Robert Axle Project Review

We had this moment of realization (and horror) at our house a few years ago.  I’d been towing our son’s Chariot trailer with my commuter bike and an older mountain bike.  One day my husband decided he wanted to mount the trailer to his fat bike and we suddenly realized we had a problem.

Clearly, we’re not alone.  With more and more bikes being designed with a rear thru-axle, lots of parents are left wondering what to do.

Fortunately, there is a fix thanks to the Robert Axle Project.  Recognizing this serious problem (well, serious for all us bike lovers), the founders–Chris and Katy Brice–created a thru-axle that works with bike trailers

We’ve been using ours for a while now and can safely say that the Robert Axle Project is a godsend for parents itching to get outside.

May 2023: Updated price information and additional competitor.

Review in a Nutshell


  • There’s a compatible axle for every imaginable bike
  • Easy to install
  • Durable, sturdy, and safe


  • Choosing the right axle can feel a bit overwhelming

Price & Where to Buy:

The Robert Axle Project Kid Trailer Axle Detailed Review

Choosing the Right Axle Can Feel Overwhelming…But Is Worth The Effort

The crazy thing about thru-axles is that they come in about a billion different lengths and thread pitches.  (Ok, a “billion” is hyperbole but that’s kinda what if feels like when you’re trying to figure out which axle you need).   

Fortunately, The Robert Axle Project has created a handy-dandy Axle Finder tool on their website.  Unfortunately, I couldn’t find my bike (an Ibis Mojo 3) in the tool.  I’ve been told that it IS in the tool, and I can totally believe that this was some sort of user error.

axle finder
The Axle Finder helps customers locate the correct axle for their bike

Luckily, the folks at The Robert Axle Project are super cool and helped me find the right axle.  (Or, so we thought). 

When I opened the package, there was a paper instructing me to check the length and thread pitch to my existing thru-axle.  The thread pattern looked a little off, but I decided to install it anyhow. 

The instructions specifically told me NOT to do this.  (Listen to the instructions folks)!

In any case, I figured out pretty quickly that the axle wasn’t going to work and stopped before I stripped the darn thing.

Once again, the folks at Robert Axle Project helped me out, and I got the correct axle this time.  To make a long story short, it turns out finding the right axle might not be easy, but it’s totally worth it, as you’ll see below.

robert axle two different threads
Two Robert Axles; two different lengths and thread pitches

Many axles also come with the length and thread pitch measurements printed on the axle (mine didn’t).  So it’s probably worth your time to remove your existing thru-axle and figure out exactly what you need before ordering.  

Installation is (Relatively) Easy

Once you have the correct thru-axle, installing it is a cinch.  Unthread the existing thru-axle, and thread in the new one.  

installing The Robert Axle
Installing the Robert Axle on my Ibis Mojo

The difference between the Robert Axle and a typical axle is that the Robert Axle has a stainless steel 10x1mm threaded stud at one end. You use this end to secure the mounting mechanism provided by your trailer manufacturer.  

While this is a pretty straight-forward process, it does require tools and a bit of time.  Compared to mounting a trailer to a standard quick release skewer, The Robert Axle does take some time and energy.  

The Robert Axle in Use

Once you have the axle installed, everything else is smooth riding.  I used my Ibis Mojo 3 to tow both our Thule Chariot Cross trailer and our Hamax Outback.  It worked great with both trailers and there was no noticeable difference between using it on the Ibis and my other bikes.

Robert Axle in Use

After putting some miles in on bumpy gravel, I did check to make sure both the axle and the end bolt were still secure, and they were.  No surprise there–the thru-axle construction is solid.

As far as compatibility goes, The Robert Axle Project works with pretty much any trailer you can come up with.  As mentioned we used it with both a Thule trailer and a Hamax trailer, but you can also use it with Burley, InStep, Croozer, etc, etc, etc.

Other Awesome Thru-Axle Solutions from The Robert Axle Project

Thru-axle problems aren’t limited to bike trailers!  That’s why The Robert Axle Project has created other products for cargo racks, trainers, and more.

Comparison Chart: Alternatives to the Robert Axle Project

Not so long ago, The Robert Axle project was really your only option for using a thru-axle with a trailer.  Today, however, more manufacturers are jumping on board. 

Burley has created their own thru-axle as has Thule.  While both are great products, they do not offer as many length/thread pattern options as The Robert Axle Project, so you may be forced to the latter anyhow.

Thru-AxleMSRPNumber of Different Length/TP Combinations
The Robert Axle Project$6215
Burley Thru-Axle$605
Thule Thru-Axle$705

Another new, cheaper option is the one from Amazon*. This will work best if you already know what thread pitch your bike has. (Pull out your existing axle and see if it says). Although it’s more affordable, it doesn’t have as many length/thread pattern options as Robert Axle.

Bottom-Line: A Thru-Axle Solution for Every Bike and Situation

Whatever bike you have, whatever trailer you want to tow (or trainer or rack you want to use), Robert Axle Project probably has a solution for you.  We found the company easy to work with, the thru-axle to be durable and safe, and any expense or effort to be well-worthwhile to get outside with the kiddo.

Learn More About Biking With Young Kids

About The Reviewers

rascal rides family

The Rascals are a family of three. Kristen (mom), Blair (dad), and Parker (kiddo). We started Rascal Rides when Parker was born and we didn’t want to give up our passion for biking. As we learned, we shared. Over the years, we’ve tested hundreds of kids bikes, helmets, bike trailers, and more.

Kristen is a USA Cycling certified coach and loves to share her passion for biking with other families. Blair is a bike geek, mechanic, and mountain bike junkie. Parker is our resident tester and inspiration.

If you see us out on the trail, make sure to say hi!

1 thought on “Robert Axle Project Review: A Thru-Axle for Bike Trailers”

  1. Hi- I have a Bob trailer which i fit to my bike with a normal skewer – however I have just got a new bike with a Through axle.

    I need a through axle with fittings for my Bob trailer at both ends – do you do such a product?


Leave a Comment