# Bike Trailer Shopping Cart

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The idea for this bike trailer/shopping cart was due to a new grocery store opening near my home. The problem I had was, it was a little too close to drive to, but too far to walk. If I had something for my bicycle, that’d be the perfect transportation.

As you look at PHOTO 1, the amassment of PVC joints and pipes is a lot, but if you break it down into steps, it can be an easy build.

## Step 1: Cart

What’s needed:

• 10’ = 1-¼” PVC Pipe (RED)
• 10x = 1-¼” PVC T-Joint (BLUE)
• 2x = 1-¼” PVC 90 Elbow (YELLOW)
• 2x = 1-¼” PVC Coupler (GREEN)
• 100 pk = #12 x ½” screws (for the rest of this project) PVC glue (for the rest of this project)
• 10x = Red arrows point at short length of PVC pipe to hold joints together. Make this length of PVC just enough to join joints with maybe a ¼” gap between them. Mines is not quite that, but it doesn’t need to be exact, just all the same.

Starting with the platform of the cart, construct something resembling PHOTO 2 using the highlights in the photo as a guide to what PVC joints you need. The lengths of the PVC pipe, in red, can be any length to accommodate the size of cart you want.

This is a cart that will endure lots of stresses. Along with glueing joints, I also use #12 or larger screws. This adds some strength to keep the pipe from jiggling its way out of the joint, which I’ve encountered. Each joint has screws about ⅜” O.C. from the edge. 2 screws on the bottom of the structure, then 2 more, about 120-degrees from the 1st two, wherever there will be no contact with other pieces.

TIP: Using screws (no glue) can be nice for PVC projects like tables or even chairs, because if you decide to get rid of the project in the future, you can unscrew everything and reuse the joints and screws (I wouldn’t recommend resusing pipes). This is a great option considering the cost of PVC joints.

## Step 2: Rear & Side Rails of Cart

What’s needed:

• 10’ = 1-¼” PVC Pipe - unless you have leftover (RED)
• 6x = 1-¼” PVC 90 Elbow (YELLOW)
• 6x = Green arrows are connections not glued or screwed - pushed into place

The side rails in PHOTO 3 and front rails in PHOTO 4 are removable, so no glue or screws where the rails connect to the cart. Construct something resembling PHOTO 3 and PHOTO 4 using the highlights in the photo as a guide to what PVC joints you need. The lengths of the PVC pipe, in red, can be any length to accommodate the size of cart you’ve built in Step 1. Keep in mind the height of the front rail in PHOTO 4 will be important later, because it serves as the shopping cart handle. See instructions further on in this process.

## Step 3: Front Rail

What’s needed:

• 10’ = 1-¼” PVC Pipe - unless you have leftover(RED)
• 2x = 1-¼” PVC T-Joint (BLUE)
• 4x = 1-¼” PVC 90 Elbow (YELLOW)
• 2x = 1-¼” PVC Cap (GRAY)
• 4x = Red arrows point at short length of PVC pipe to hold joints together (same as Step 1)
• 2x = Green arrow = not glued or screwed (same as Step 2)

This rail serves as the joint to where the tow bar connects to the cart. These rails are also removable, so no glue or screws where the rails connect to the cart. Construct something resembling PHOTO 5 using the highlights in the photo as a guide to what PVC joints you need. The lengths of the PVC pipe, in red, can be any length. Try to get approximately the same height as in the photo. One thing not visible in PHOTO 5 is the PVC Cap and the PVC pipe just below are glued together, but it’s not glued to the PVC T-Joint. This section serves as water-resistant storage (PHOTO 6) for a screwdriver I keep handy. The similar vertical piece on the other side holds the removable screwdriver bits in an Airborne container. You’ll have to find a way to add a bottom so things don’t fall all the way through. I stuffed a plastic shopping bag in mines.

Right now, you should have the two vertical rail pieces without the adjoining cross-member (red horizontal piece in PHOTO 5). Put both vertical rails into the cart. Be sure they are all the way in so you get a good measurement on the next step. Measure the distance between both vertical pieces, taking the measurement from the apex of one of the T-Joints to the apex of the other T-Joint. This should be approximately the length of the horizontal cross-member. Cut a piece of PVC pipe and test its fit. You can disregard glueing this piece, but do put screws to keep it in place.

## Step 4: Tow Bar

What’s needed:

• 10’ = 1-¼” PVC Pipe - unless you have leftover (RED)
• 2x = 1-¼” PVC T-Joint (BLUE)
• 1x = 1-¼” PVC 90 Elbow (YELLOW)
• 1x = 1-¼” PVC 45 Elbow (F)
• 2x = 1-¼” PVC to Male Threaded (E)
• 1x = 1-¼” PVC to Female Threaded (A)
• 2x = 2” hose clamp (B)
• 2x = zip tie (D)
• 4x = #12 screw (C)
• 3x = Red arrows point at short length of PVC pipe to hold joints together (same as Step 1)

The Front Rail connection of the tow bar, shown in PHOTO 7 and PHOTO 8, are made from 2 T-Joints and a PVC to Female Threaded joint. PHOTO 8 illustrates how this mechanism connects to the Front Rail from Step 3. The T must be cut in half, then the hose clamp is used to hold the two pieces together around the Front Rail. The ability to tighten or loosen the hose clamp allows the tension to be adjusted for how easily the tow bar swings up and down. The zip ties, D, are on both sides of the T and prevent the hose clamps from working their way off the T. Screw C, on either side of the Front Rail, prevent the tow bar connection from sliding too far left or right.

PHOTO 9 is a little easier to build. Get all the pieces shown and build it as close to what’s shown. Lengths of the PVC pipes depend on your bicycle wheel size. This one was made for 20” wheels and should go right up to the back side of the seat post.

## Step 5: Tow Hitch

What’s needed:

• 10’ = 1-¼” PVC Pipe - unless you have leftover (RED)
• 10x = 1-¼” PVC T-Joint (BLUE)
• 2x = 1-¼” PVC Cap (A)
• 1x = 1-¼” spherical door knob with threaded female hole (B)
• 1x = 1-½” S.S. bolt to fit threaded female hole in door knob(C)
• 4” = ¾” PVC Pipe (D)
• 1x = #12 screw (E)

Build the colored part of the hitch in PHOTO 10. The part of the T that slides over the seatpost will be quite a bit larger than most seatposts, so sort lengths of 1-¼” PVC pipe on each side of the T helps to take up some of the excess space between the seatpost and the PVC. The other PVC pipe needs to be long enough to hold the part of the hitch that will attach to the threaded end of the tow bar.

PHOTO 11 shows a close-up of what’s needed to build the threaded connector of the tow hitch.

PVC Cap (A) - I used a hole saw to cut away a circle small enough to keep the spherical door knob from coming through, but large enough to allow the bolt that will be screwed into the knob as much room as possible to move to all sides. This allows the tow bar to work in the same way as a tow hitch on a utility vehicle towing a trailer.

Build the rest of the tow hitch using PHOTO 10 and PHOTO 11 as a reference. Drill a hole in the PVC that S.S. bolt (C) passes through, fitted, but not a tight fit. The ¾” PVC, stuffed into the larger PVC and held in place with the #12 screw, is a filler to keep the S.S. bolt from moving around too much, which in turn keeps the hole it passes through from enlarging over time from wear and tear.

PHOTO 12 shows a hole in the PVC and a hole in the seatpost. The hole in the PVC is for ease of aligning the screws next to it with the hole in the seatpost. The hole in the seatpost should not be drilled to large to avoid weakening the seatpost. The screw should fit snug into the seatpost hole when tightened. This keeps the tow hitch from spinning around the seatpost, which can get in the way when pedaling. There are other options you can try if you don’t want a screw going through your seatpost. Feel free to update this instructional if you like.

## Step 6: Put It All Together

You will have 3 sections of the bike trailer that only need a screwdriver to assemble/dismantle. Screw the tow bar threaded PVC end into the threaded female end on the cart (PHOTO 13). PHOTO 13 shows a screw being tightened. This screw is a safety you can add if you like to keep the tow bar from turning in the threaded female connection. You should then have something that looks like the PHOTO 9 in Step 4.

PHOTO 14 shows the end of the tow bar that connect to the tow hitch on the seatpost. Lower the tow bar into the threaded cap and tighten the cap when the threads on the tow bar are aligned correctly. Note: The cap needs to be tightened snug, but not a lot. It doesn’t unscrew that easily, so you won’t have to crank it down too hard.

That’s it, as far as what you need to get to the grocery store. Once you get there...

## Step 7: Shopping Cart

The shopping cart is fairly simple to setup. Unscrew the cap to release the tow bar from the seatpost. Remove the screw used to secure the other threaded end of the tow bar to cart connection. Now unscrew the tow bar from the cart. For myself, I leave the tow bar wherever I lock my bicycle, since no one seems to take it. You may have different circumstances where you lock your bicycle, so take appropriate precautions.

Reconfigure your cart into a shopping friendly cart by:

1. Remove both rear rails and also, both removable pieces of PVC from the front rails, and swap these pairs of pieces as shown partially done in PHOTO 15.
2. You’ll end up with what’s pictured in PHOTO 16 and PHOTO 17.
3. When you done shopping, you do the reverse to cart everything home.

One thing nice about using these plastic tubs is that if you also bring some bungie cord with you, you can stack the tubs and secure them with multiple bungies. For this purpose, I have hooked screws sticking out of the top of the PVC that is the perimeter of the cart.

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## 7 Discussions

It was cheap only because I scavenged the wheels from a wagon I found in the garbage. FYI, someone commented on no design for the wheel assembly, which is true. It's basically a threaded rod from one wheel to the other. You'll have to figure out how to attach the wheels to the axle to the cart. My way wasn't the greatest. I'd do it different now that I look back. Price, by the way, would be about \$100. That tow hitch/bar part was on the pricey side. So were all the screws I use to hold the PVC instead of the usual glue. Hope this helps.

You left out the wheel assembly. What do you use for an axle? How is the axle connected to the cart and to the wheels? What kind of wheels are those and where did you find them? What is the front wheel and how did you attach that?

funny you mention that. When we go to Magic Island for beach picnics, the trailer becomes the picnic train ride for the kids.

This would be so convenient! Nice work!