When you have gathered all
the materials needed, we are ready to begin the
destruction. Carefully cut the frames of the two bicycles
forward of the seat tube.
File down any
protruding stubs of tubing, leaving a smooth surface. Now
you will need the local bike shop. Take the rear wheel
assemblies you just freed to the bike shop to have them
“remove the crank”. You’ll want it taken down to a “bare
bottom bracket tube”. Ask them to measure the I.D. of the
bottom bracket tubing, and write it down. When they’re done
scratching their heads, you will have two frame sections
with wheels; after removing the seat and seat post there
will be nothing else that can be removed except the wheels.
If there is seat retention hardware, hold on to it, you can
use it later.
Now you can shop for and
buy the large diameter tube to join the frames together.
You want to buy the largest size that will fit into the
bottom bracket tubes of the frames you have. Thinner wall
is better, I’d look for 1mm (.040”) or .050” thickness.
1/8” will weigh a figurative TON! 4130 is the best alloy,
any 4xxx series will suffice. 1010 steel will also
contribute to a porcine aspect to your cart. Remember,
although your dog is pulling it, you’ll be lifting it in and
out of the car. “Simplicate, and add more lightness” as per
William Stout is our motto.
The length of the tube you
buy will be determined by the distance between the wheels
desired (the “track”). Set the two frame sections on the
floor, resting on the tires and the bottom bracket tubes.
Sit between them to get a feel for the correct distance.
Then measure from the OUTSIDE of one bottom bracket tube to
the OUTSIDE of the other. You should get a number within a
couple of inches either side of thirty inches.
At this point we have two
ways to proceed. One we will follow if we wish to be able
to break down the cart for easier transportation, the other
will yield a non-collapsible cart. The non-collapsible cart
will be more rigid, but the other will hold up to anything
short of Mr. Toad’s Wild Ride.
For the take-down style
cart: Lay the frames out as you did before, only this time
slide the bottom bracket tubes over the large diameter
tube. Place one frame section at each end of the large
The large diameter tube must extend all the
way through the bottom bracket tubes, and be flush with them
on the ends. Now drill a ¼” hole through both tubes in the
middle of the bottom bracket tube, flip the assembly over
and drill a corresponding hole opposite the first. Two ¼”
bolts, 3” long, Grade 8; with nuts, washers and lock washers
will complete the assembly. By removing these bolts you can
effect the disassembly for storage or transportation.
The alternative is a rigid assembly. Weld the large
diameter tube in place as described above. The local
bike shop can assist you in having this done. At this
point you should have something that looks like this. Take
this opportunity to paint your cart.
Finally, we need to have a
way to hitch our dog to the cart. We will use the two
shovel handles for this purpose. Measure the I.D. of the
seat tube where the seat post fit. Turn down the handle for
a length of three inches to a diameter that will fit inside
the seat tube. The clamping method used to secure the seat
posts will suffice to hold the traces; should you wish for a
more secure mounting method, the tubes and traces can be
cross-drilled and #10 hardware used to secure them together
This completes the
assembly of the frame for our cart. Seating can be provided
by attaching a piece of ¼” plywood using pipe clamps or
plumber’s tape. A foot rest can also be built and attached
to the seat.