We needed a way to store our winter tires out of the way, but have safe easy access. This cart also holds our tire-changing tools. Before, we stacked them on a flat dolly but they wobbled and also didn't hold our tools where we needed them. This tire cart takes up about the same floor space but is much more convenient and safer to move around.Our full measurements are included but you can scale up or down if you compare your tire measurements to ours. If you build it larger, more bracing (wood blocks or metal brackets) may be needed.

Supplies

Construction screws (Recommended length was 2.5" or 2.75" for most of it)
Power drill, with appropriate driver and drill bits, for your screws
Carpenter's glue
Measuring tape
FOUR 2x4 x8ft (If your car can't carry 8ft, have the store cut TWO at the 31" mark, and TWO at 48")
ONE 2x4 x10ft (ask store to cut in half)
TWO pcs scrap mdf, melamine, or plywood, about 24x12 inches (OR purchase a 2'x2' pre-cut panel)
FOUR casters (any size, but with a minimum weight rating of your 4 tires, your tools + the cart itself which is ~30 lbs)
Optional: assorted angle brackets if desired, and/or scrap wood for extra bracing
Saws to cut your 2x4s, and plywood. We used a miter saw and jig saw.
Clamps to hold your pieces steady and straight/flat/square.
Speed square or other square edge.

Step 1: Measure Your Tires

Take the measurements of the outer diameter, and the thickness of two tires together. These measurements will determine the dimensions of the cart as follows:

Outer Diameter: since you will roll the lower tire out of the frame, the diameter determines the space from the lower shelf to the upper shelf (plus wiggle room of 1-2 inches).

Our diameter was about 25" and we added 2" clearance, which means the distance from the lower shelf to the upper is 27".

Thickness: this will determine the inside width of the frame.

Two of our tires were 18" thick and we wanted a snug fit, so our inner width will be 18".

Step 2: Calculate Tire Chord Length

We wanted to make sure the tire, resting on two 2x4's, won't touch the ground.

The casters we bought were 2.5" tall. The 2x4 height is 3.5". So the top edges of the lower frame will be about 6" off the floor. The top edges are also the where the tire rests, which can be measured as a line across the edge of the tire. This is the chord of the circle (not tangent as seen in my notes lol). We want that line to be less than 6" from the edge of the tire. We decided 1" clearance is fine so the chord needs to be 5" from the edge of the tire.

Our measurement came to 19.5", so that was the dimension of the inner length of our cart.

Step 3: Sketch Up Dimensions

Based on our measurements and calculations, the base frame had to have inner dimensions of 18" x 19.5". We decided to have an extra section to one side, for a bin to hold our jack, plus impact wrench, sockets, tire iron, and torque wrenches.

The dimensions for that side were initally based on our jack, which would stay in the lower bin. The upper bin could not hold all the other items how we wanted, but we may add hardware to hang the oversized/odd sized items.

We also know that the distance from the lower frame to the upper frame had to be 27" to allow the lower tires to be lifted and rolled out from the frame. See our diagrams for how we conceptualized the layout.

Step 4: Cut List

The cuts we made were as follows:

using the 10ft 2x4, make 6 pieces of 19.5 inches
using two of the 8ft 2x4, make 4 pieces of approx 48 inches
using the other two 8ft 2x4, make 4 pieces of 31 inches (you will get 3 pieces from the first 2x4, and one piece from the other 2x4, with a nice leftover piece for future use)
scrap melamine we had, to be cut with notches and screwed to the bottom of the "tool" side. I didn't mark and cut these till after the assembly was done.

Step 5: Assemble the Upper and Lower Frames

We forgot to glue some of the connections, but we recommend using glue before the final assembly.

Lay 3 of the 19.5" pieces out, along the narrow edge, like joists. Sandwich these between two 31" pieces and mark where the two ends will be attached. The middle piece needs to be placed so that it is 18" away from the end piece.

Clamp to a table top or a piece of plywood, and glue and screw together from the outside edges.

Step 6: Attach the Uprights

Using clamps, we placed two uprights through the "tool" side of the frame, to ensure the tires have the most support.

We then added the two outer uprights to the other end, as seen in the pictures. this way, the part of the frame holding the tires is a clean inner rectangle. Be sure that no screw heads or points are protruding on the inner rectangle.

We worried that pushing or pulling this frame, when loaded with tires and tools, would tend to skew the frame. So from scrap 2x4s we added blocks to give angular bracing. The final pics show the blocks along the side.

Step 7: Attach Plywood and Casters

To create a bin on the tool side of the cart, we used scrap melamine and cut notches with a jigsaw, to fit around the 2x4 uprights. Then we screwed this to the underside of the tool box. Casters were added to this side of the cart.

On the tire side of the cart, before adding casters, we needed an equal thickness of melamine or plywood under the frame. Scrap pieces went on those two corners on the tire side, and then we added the casters.

Step 8: Load Up Your Tires and Tools!

Now you can roll two tires onto the lower frame, and carefully lift two more into the upper frame. The tools you use for tire changes can go into the tool bins you created. If the unit seems heavy or has any weak spots, add scrap wood or metal brackets wherever you think it needs bracing. Just be careful about screw placement and length, and make sure you keep the tire side clear for loading/unloading them.

We bought galvanized gate handles which we will attach later, to help move it around the garage.

If you made this project, please comment with how it turned out!