This is not an original idea, recently you can buy these belts in fairs and markets, and six years ago opendesignclub wrote how to make tread belts (you also could read his instructable).
I used some thinner bicycle tires for my project, the one you use on your technical racing bicycle, or on your stylish fixed gear one. Usually these tires are also coloured and they could have stripes along all the tread, so you can obtain very trendy belts. Don't worry if the tread is not in good conditions, that's exactly the purpose of this project, and only if you're so lucky to cut your tire right away with a glass you will have a brand new belt. In this instructable I describe how I made four different belts from one very consumed coloured tire, two pierced black ones almost new, and a wrecked mountain bike tire.
Step 1: Materials
In the picture you see that the tread with blue stripes also has an hole, and I tried to hide it with the belt loop. So if you have a damaged area you have tho options: cut it away, since you don't need the full length of the tire, or hide it under one or two loops.
You can find many different types of belt buckles on eBay, and some of them are very funny, but I chose to use some classic ones.
Step 2: Measure and Cut
Now you can cut the edges so to obtain the exact width of the buckle. As you see you have to narrow the last 7-10 cm of strip, alternatively you can cut all the entire tread wider as the bar length.
Step 3: The Prong Slot
Step 4: Punch Out Rivets Holes
Then cut a stripe from the piece of tread you split up, the length has to be the exact measure so that it can wrap the belt with no overlapping.
Step 5: Belt Loop
Then insert the buckle, close the first rivet, insert the loop and add the last rivet.
Step 6: Adjustment Holes
Look the following table to determine the right length, then punch out the center hole at the waistline distance from the end of the buckle, and add two or more holes at each side of the first one.
Step 7: Last Finishing
My first trendy belt is ready to wear, let's see what we can obtain with a bit different tire and expedients.
Step 8: Another Belt
I decided to cut the first belt to fit the smaller buckle I have, which is a standard 3.5 cm one, and I didn't leave the tread centered, instead I cut it leaving the writing well in view, so that the carved tread occupy half width.
Step 9: Frame Connections
Step 10: Loops
The I fastened them with the stapler as before, but this time I decided to try to heat them up, to see if heat will make them keeping the shape. That works very good, you can either ironing them, or close them in a metal peg and put all in the toaster for 5 minutes.
Step 11: Punch Holes
Step 12: Ready
Step 13: This Is Centered
You know by now the full process. Here I punched the slot and inserted the belt in the buckle. Then I punched out the holes for screws. Now measure the exact length and make the size holes as described before.
Step 14: Another One Completed
As you see these black tires are very appropriate for not very garish belts, but you can obtain gorgeous results with almost every type of treads.
Step 15: Last the Wrecked One
Step 16: Let's Promote This New Ecologist Trend
Then I punched the holes, refined the ends and connected the buckle. As you see it's worthwhile, maybe not so trendy, but undoubtedly sturdy!
So, what are you waiting? Go looking for a nice buckle and an used tire ;-)
Step 17: [UPDATE] New Creations
Give a look also to another belt I made from a white tire and a huge belt made from an old Superga tire.