When you have a lot of stuff to carry and doing so on your bike isn’t an option—or your bike is already loaded up—a trailer is a great way to expand your capacity. BOB trailers in particular can carry a ton of weight and don’t have an adverse affect on your bike’s handling. They even work on singletrack.
Thru-axles offer similar advantages: they create a stiffer swingarm, they’re almost impossible to install incorrectly, and they’re safer because the wheel can’t come off accidentally.
The trouble is that the hitch attachment mechanism for a BOB trailer and many other trailers was designed around a quick release rear skewer. Now that mountain bikes and many road bikes have adopted 12 mm thru-axles at the rear hub, attaching a trailer isn’t an option.
Enter The Robert Axle Project, a husband and wife team of avid mountain bikers, trail builders and explorers who love using trailers. They set out to solve the problem of attaching their trailers to their modern mountain bikes by designing and building a special thru-axle that has an attachment point for trailer hitches. Compatible versions are available for BOB trailers, hitch mount or yoke mount kids and cargo trailers, or even resistance trainers for riding indoors.
Bike “standards” being what they are these days, there are also several widths and threads available for all kinds of different bikes, including fat bikes and the new Boost spacing. If you’re not sure which one you need the Robert Axle Project website will walk you through it.
The solid axles are CNC machined from 7075 aluminum in the US, and are installed or removed with a simple 5mm hex wrench. They sell for $56 to $69 through your local bike shop or straight from the website.