I had some old bike tubes I had set aside for crafts. I wanted to try experiment sewing with them. I found this to be the easiest (and most practical project).

Supplies

Home Depot Bucket (Or any Bucket)

Soap

Water

Sewing Machine-Mine is a Janome 2212 and worked well but Heavy Duty Machines may be more ideal

Sharp scissors (But not Fabric)

Rotary Cutter and Mat (optional)

Square Tool or Ruler

Chalk

Thread (Polyester or heavier cotton)

Iron (optional but recommended)

Parchment Paper (optional but recommended)

Step 1: Acquire Bike Tubes

You may have some on hand if you recently blew out your tires. If not, most bike shops are happy to give you some old tires.

Step 2: Prepare

Cut off air valves

Step 3: Cut

Cut the tires so they are no longer round. This will prevent dirt and grime from getting stuck inside when you wash them.

Step 4: Soak

In a Home Depot bucket (or any large bucket) soak the tires in a mix of soap and water, occasionally stirring the water to remove grime.

Step 5: Let Dry

Hang out in the sun to dry. The longer they are in the sun the more workable the tire will be.

Step 6: Iron (Optional But Highly Recommend)

(I would recommend ironing if you have a more basic machine because it makes the tire thinner. You can skip this step if you have a HD machine.)

Set up your ironing board in a well-ventilated place. Lay down your tire flat and place Parchment paper on top to prevent ruining your iron. I definitely recommend doing this for a fatter tire (mountain bike) or smaller kids' tires.

Step 7: Cut

Cut Wallet Pieces

Main Cash pocket 2x: 18 cm x 9 cm (7.5 x 3.5 inches)

Change Pocket 1x: 6 x 4 cm (3 x 2.5 inches)

Step 8: Tension Cheat

I created this tension test cheat sheet, and I'd recommend you do the same. For my basic model, 9 (the highest tension) gave me the best results. If you have a HD (Heavy Duty) Machines the tension may be different.

Step 9: Sew Borders

Position your tire just smidge before your needle about 1/4 inch or 1/5 cm away from the edge (See Photo). This will create a borders for each of your pieces. It will make the end result look more finished.

Step 10: Sew on Inside Change Pocket

About 3 cm or 1 inch from the end, sew on the small pocket. Make sure to start with your needle directly penetrating both pieces or your feed dogs will move the bottom fabric but not the top. Make sure to back stitch.