How to Carry a Bike With Another Bike

For years I’ve wanted to tow a bike with another bicycle and had this towing solution tucked away in my garage. Now I finally want to make it available to everyone! What do you do when you have one person and need to move two bikes? Maybe you’re taking a bike to be repaired, or your dirt jumper to the bike park, or picking up your friend at the train station and don’t want to drive there. Or you left your bike at the bar and need to pick it up the next morning. I searched all over and couldn’t find a solution that was compact, easy, and did not involve disassembling the second bike, so I designed my own device to tow one bike behind another.

Updated 6/17/2023

Attached bike ready to tow, thanks to my assistant

Ready to go! And it won't fall over!

Some people online had elaborate contraptions with hinges, hitches, cages, and wells to hold onto the second bike, but I decided to take advantage of the fact that a bike already comes with a front end that has two perfectly situated sets of bearings (when holding the wheel, the wheel spins to allow up/down movement of the rest of the bike, and the headset rotates left/right so that the bike can trail behind) and also a rear wheel that spins and can carry the rest of the load. No need to have the whole bike off the ground, and no need to own a cargo bike!

I appreciate other people's creativity but I couldn't find an existing system that wasn't complex, required disassembly, or worked particularly well

The design I made is pretty simple but IT WORKS! I encourage you to get the parts to build one of these yourself, try it out, and then report back to me how it went, along with your ideas for improvement. I’ll keep updating the parts and designs here as I improve them over time.

How the towing system works

The front wheel of the trailing bike is lifted off the ground and onto a hook attached to the rear rack of the first bike. The wheel is secured in three places (three holding points will hold the wheel steadily in place) — on the hook, with a swing-out arm that attaches on the back side of the wheel near the downtube, and at a lower point on the wheel by the first bike’s chainstay.

Detail view of how the bikes attach together from the non-drive side

Detail view of how the bikes attach together from the drive side (bungee cord removed for clarity)

Actually towing a bike

1. Place wheel onto hook on rear rack, cinch down strap
2. Place lower part of wheel against strap on chainstay and cinch down. Note that it’s usually best to have that strap set back slightly (you’d have to push the wheel toward the rear) to improve foot clearance when pedaling
3. Swing support arm over to rear side of wheel and cinch down.
4. Attach a bungee cord from your rack around the head tube of the towed bike—this is the secret to not having the bike flop over when making tight turns!

That’s it! No need to disassemble any part of the bike. When not in use, the support arm swings around and can be attached to the top tube where it does not interfere with pedaling.

Materials

I included sources for online purchases, though you would likely have luck with the small parts selection at your local hardware store for some of the regular hardware, and those come in very small packs. Note that some of the links are affiliate links (win-win, thanks for your support!).

Item	Quantity / Notes	Sources
U-Channel, aluminum, 1/2" high legs, 1-1/2" wide x 8ft	Need to cut two pieces: 12", 8" The main structure	Grainger McMaster
Wing Nuts, 1/4-28	Need 3 from a pack Something easy to tighten by hand, could also use a knob	Amazon Grainger McMaster
Female Rod End 1/4-28 x Male 1/4-28, right handed	1x This is the swivel joint	Amazon Grainger McMaster
Threaded Rod, 1/4-28 x 2 ft	1x Will be cut down to exact size, ~18"	Amazon Grainger McMaster
Socket Head Cap Screw, 1/4-28 x 1-1/4"	Need 3 from a pack Main connection between two rails	Amazon Grainger McMaster
Split Lock Washer, 1/4"	Need 7 total from a pack Used in multiple places	Amazon Grainger McMaster
Hex Nut, 1/4-28	Need 5 from a pack Used in multiple places	Amazon Grainger McMaster
Recycled Rubber, 1/8" Thick, 12"x12"	1 sheet (need two pieces 1"x6") Any thin rubber will do	Amazon Grainger McMaster
Bungee cord with hooks, 24"	1x Almost any will do	Amazon Grainger McMaster
Instamorph	6 oz package or larger Makes the two custom hooks (These parts could also be 3D printed!)	Amazon Manufacturer
Voile Straps	3x 16" nano or 20" regular straps work well. Depends on your tire/rim. Sometimes you can find "seconds" on eBay.	Amazon Manufacturer
Sugru moldable rubber	1-2 packs of whatever color you like This stuff is so useful! (Also possible to 3D print these bumpers)	Amazon Manufacturer

Note on sourcing nuts/bolts/washers: Your local hardware store will likely have the common stuff in small bags for ~$1 which is perfect. Grainger and McMaster let you find exactly what you need and cost a little more, and Amazon is like the Wild West. I ended up getting most things from Grainger.

Note on bolt length: 1-1/4” length was good for me with a rack thickness of 10mm. Can make longer if your rack tubing is really thick or if you want to add washers to protect the aluminum channel.

Why use English thread sizes and not metric? Mostly because the only small ball joints I could find when getting started came in English fine-threaded sizes (I chose 1/4-28) so the rest of the hardware cascaded from that. That said, this M6 ball joint from McMaster should work and would allow all the hardware to be simplified to M6x1. If I was starting fresh, I'd use M6!

Tools needed

• A drill for the 1/4" holes (same holes work for M6)
• Wrenches for the 1/4" (or M6) nuts
• Glue to attach the rubber to the aluminum channel, I used Gorilla Glue
• Saw to cut the aluminum channel and threaded rod

Assembly

This is still an early version of the design so you might need to make slight modifications to be sure it will clamp correctly to your rack, etc. For example, confirm the width and height of the rails on your rack which can impact the spacing of the main mounting bolts and also how long you want those bolts to be. But the dimensions I have should work for most racks.

Shown here are Wrap-N-Straps, but I've since learned about Voile Straps which work much better.

When making the Instamorph "hook" that goes at the end of the threaded rod to attach to the towed bike's front wheel, make whatever custom shape you think will work best to interface with your wheels of interest. Probably lots of room for improvement on my design. There are actually two nuts embedded in the plastic so that the rod can attach securely. To do this, I threaded the nuts onto the rod and formed the Instamoph around the rod. The plastic will not adhere to the metal rod, making this dead simple and effective.

Also please note that his is a hobby/DIY project and not a commercial product that has undergone rigorous testing. Use your head, make sure everything is mounted securely, and ride safely!

If there is demand I might start creating pre-made kits of these parts — let me know in the comments or email if you’d like that.

Tips

1. Rack selection — I found that a sturdy rack like the Topeak Explorer MTX (REI, Amazon) holds a bike very steadily and doesn’t wobble back and forth like a previous cheapo rack I used (which eventually broke).
2. Dealing with fenders — If the trailing bike has front fenders, try attaching the strap underneath the fenders to allow the wheel to move freely and not squish the fenders. On some bikes it’s probably fine to wrap around the fenders though.

So what do you think? Have you tried to solve this problem yourself? What worked and what didn’t? If you try building one of these devices please let me know in the comments!

Cheers,
Mike