Road Train!

Up here at Chez Ravenfamily, we're too rural to get doorstep recycling collections. But as you've probably noticed, we're big on that environmental gig. So as time goes by, we tend to build up a lot of cans and plastic bottles that need to go to the recycling centre. Here's the dilemma: we've got a load of lightweight stuff to haul, but only one person to do the hauling. We've got two bike trailers, but one person can only pull one trailer -- can't they?

The BOB Yak is a great trailer, and we have two. It fits to the bike with a custom quick-release that replaces the stock QR in your rear wheel; there's a little clevis pin to secure everything. Nice and simple. And that got me to thinking: What if you hooked one BOB up to another? Why, you'd have a road train - a double-trailer articulated monstrosity that only the mad would want to haul.

That'd carry a load of recycling all in one go, and only at moderate-to-high risk of injury, failure and horrific expense. Fantastic.

Photo: Trailer spindle detail
The regular BOB Yak quick-release spindle, packed out with spacers.

The modification is really easy: the BOB's single wheel has a standard front 100mm hub. You whip out the stock QR and replace it with a BOB-standard rear QR, packing out the extra 35mm with some old axle spacers scrounged from the shed or your local bike shop.

Now you'll note that this puts the twisting load of the rear trailer all on that skinny BOB QR, and that's something which is famous for bending even when properly fitted on a sturdy bike. Okay, so this is for super-light duty work. At least until I come up with something stronger - a properly-machined spacer about 18mm long with an external diameter of 14mm and a bore of 5mm should do the trick.

Luckily the forces on that middle trailer wheel are pretty light: just the pull and jink of the rear trailer. At least, I hope so!

Photo: Trailers hitched together
The second trailer fits over the spindle of the first.

To assemble the train, just hook the rear trailer over the front trailer's QR and pop in the pins. As easy as pie. It looks magnificent. But will it work?

In short, yes it works, and yes it works damn well. The BOB trailer is very good at precisely tracking a bike's path - that's why it is so popular offroad, because you can take a BOB down lumpy, uneven singletrack and as long as your bike goes there, the trailer goes there. The same characteristic makes it great in tight traffic, too, as you can pretty much ride as if it wasn't there and it'll not get hung up on kerbs or vehicles.

Photo: Bike and two trailers
All hitched up and ready to roll! Don't forget: lots of lights and flags!

When you hook two BOBs together, the tracking of the lead trailer is as good as ever. The tail trailer is a little looser in its following - just by a couple of inches either way - as the general bagginess of the system adds up over each set of linkages. A couple of inches is still hardly anything, though: the double-trailer is stable at over 25mph and if you ride along the white line, both trailer wheels track it tightly enough to be comfortable.

It is a little more sketchy than the same weight in just one trailer: that extra trailer puts some entertaining tug-and-jink forces on your backside and lighter riders or whippier towing bikes might find it challenging. But with a light load, it's grand.