loading

Problem... how do you bring home a bike from the bike shop when all you have is a bike to ride?

It is my goal to be able to do all of my errands by bicycle. Unfortunately, one errand that I couldn’t do by bike is to pick up another bicycle at the bike shop, that is until now. In order to to solve this problem, I have created a bike tow rack. This rack enables one bicycle to be able to tow another.

http://www.techshop.ws/

Step 1: Take Measurements

The first task was to measure where the bicycle being towed was to be be positioned. I put the second bike up on blocks and used a bike stand to hold it in place while I measured.

Step 2: Repurpose a Chair

I found an old broken chair that someone was throwing out and I cut it up and reused the steel tubing to create this bicycle two rack. When used as a chair, this steel tubing was strong enough to support a person. Since the bike I am towing weights about 35 pounds, it is easily strong enough for this task.

Step 3: Tack Weld the Assembly

Here is the first layout of the bike rack as tacked together on the welding table. It actually took several revisions to get the placement of all of the elements correct.

Step 4: Fit the Rack on the Bike

It is critical that the vertical bar of the rack and the tire of the bike being towed are far enough back that they don’t not interfere with the heel of the person pedaling the front bike. In the first attempts, the front bar was too far forward,and the tire of the trailing bike was too far back.

I have not provided specific dimensions, but I will offer the guideline that the front vertical bar and the tire of the bike being towed can only be slightly in front of the rear axle. This exact position will dependent on the specific geometry of the two bikes, and maybe the size of the shoes that the person pedaling the bike wears.

Step 5: Creating Mounting Hooks

I continued to cut apart the frame of the chair using the seat frame for the top mounting hook, and tire support. I also bent the chair hinges to create the rack hooks.

Step 6: Further Rack Assembly

The first task of the rack is that it needs to hold the tire of the bike being towed off the ground. It also needs to stop the tire from rolling forward in the event of an emergency stop, and it needs to stop the bike being towed from falling back.

Further, the front tire of the bike being towed needs to be held in such a way that it does not interfere with its forks, which need to be able to rotate on the front axle freely to allow the bike being towed to go over bumps. Here shown is the top hook, tacked in place.

Step 7: Adjusting the Rack Welds

In this image, the rack is tacked together with a slightly different dimension than shown earlier. In the course of this assembly, I broke apart each of the tack welds and reassembled them at least three times.

Step 8: Attaching the Towed Bike to the Rack

There was a great deal of discussion about how to hold the bike being towed on the rack. In the end I just used a bungee cord wrapped around the front tire. Maybe in time I will develop a more sophisticated attachment method. I have left the top bar long to allow for a future hook that will attach around the rear of the tire.

Step 9: Uses for Bike Tow Rack

Here are images of the rack both on and off the bike. Almost everyone who has seen this design has had suggestions about what could be done.

One topic I will look at in the future is optimizing the way this frame clamps on the bike rack. Currently this rack is being held on the bike with the use of three pipe clamps. This is secure, but not elegant. Also, as discussed above, I may develop a better way to hold the bike being towed on the rack.

In practice, this is a very useful rack. In addition to being able to tow bikes with it, I have also carried large cardboard boxes that I would not have been able to tie on top of the rack.

One question I have been asked is, how do you ride with an asymmetric load. The answer is that the bike that I am towing weights only about 30 pounds, and I weigh over 200 pounds. While riding, I can easily compensate for this load on one side of the bike.

The best use I have heard for this rack is as a tool for a bike rental company. If one of their bikes breaks down, they can bike to their customer with a new bike in tow, and then use the rack to tow the broken bike back to the shop!

<p>Creative - does it make the front bike feel back-heavy? Could make the steering lighter (ie less effective).</p><p>I'm currently exploring a front-wheel clamp, (like used on car roof racks) but mounted on the front bike's rear carrier. Or welding two lugs to the carrier or even the rear triangle. Then the back bike's front wheel would be disconnected and lashed to the rear bike somewhere for transport. </p><p>Final thought is a pole flag clipped to the rear of the rear bike, so motorists have less excuse for not-seeing the towed load.</p>
<p>If you take the front wheel off of the towed bike, you'll need to provide an axle to mount the front fork on that allows rotation about what would be the front wheel's axis, so that the towed bike can move up and down to go over bumps etc. You could just clamp it loosely, but that could cause wear in the dropouts (because they're not designed to be bearing surfaces) and it could come off while riding.</p>
<p>Here's another option that looks like it would work in a pinch: Mount a pannier or backpack, and stick the towed bike's front fork into it. Tie the zipper shut around it if necessary.</p><p>See the last photo of step 2 here: https://www.instructables.com/id/Bike-rack-panniers-adventures-4-Packs-Trailers/</p>
<p>Another silly thought - what happens if the bike rental place wants to make a string of deliveries in the same general direction? </p><p>Could you fit a second rack to the towed bike, and tow a third bike? How far can this go?</p>
<p>That's pretty clever. When you have more than one bike, this might be a necessity.</p>
Could not ever see myself using one, but that is a great idea to a definite problem. Nice job.

About This Instructable

10,092views

27favorites

License:

More by pgarrow:Optimizing Drawings for FlowJet - I made it at TechShop! AutoCAD to Trotec Laser - I Made It at TechShop! Machine Carved Contour Map - I Made It at TechShop! 
Add instructable to: