Plan your armor

Before you begin with anything you should give a bit of thought into your armor, how you want it to look, what areas you want to cover, and what materials you have available.
The easy thing is to just use parts of the tires as shoulder pads, and ad-hoc whatever you have left over into other sections of body armor.

To give you an idea how much material you might use, the pictured armor's left shoulder pad is approximately 1/5 to 1/4 of the entire tire. It covers just past mid-upper armor. Keep in mind your actual mileage will vary from the size of the tire you are working with.

If you're planning on making a waist/kidney belt from the tire tread, be aware you it probably won't conform enough to make it a single piece. I would recommend cutting the tire into 3 or 4 sections and joining them with something flexible: chain, hinges, straps, etc.

Getting Materials

To make your armor you will need a few things, obviously the first is the tire you're gonna use. I would recommend just calling up the local tire places and asking if they have any tires they need to get rid of. Usually tire stores get charged an disposal fee to offload their tires, so they would probably be willing to give you one free of charge. If they ask you what you're going to do with it, you can just tell them you're going to make a tire swing.

Sometimes you can just find tires laying around. This is especially the case with truck tires if you choose to use them. While driving around on your daily commute, just keep an eye out.

Next, you will need something that you will mount your tire armor parts to. Generally either Hockey or Football shoulder pads are the stereotypical base for upper body armor, but by all means you can get creative. Since you are going to effectively destroy any pads you get, check out the used sporting goods stores or ask around to see if anyone has some they don't use anymore. I got my set of football pads fairly inexpensively off of eBay.

You will also need plenty of stuff from the hardware store. If you don't have it already, you will probably have to end up buying it all.

Hardware and Tools

In order to manipulate your tire, you're gonna need a few things.. here's a list of stuff I used in the course of making my set of armor:

• Reciprocating saw (often referred as a SawzAll): I used a steel cutting blade when I used t. You're gonna use this to cut through the tire sidewalls and the steel belt. You can also use it to cut through the bead cables but I don't recommend it. If you don't have one and enjoy manual labor, you can probably get by with a hacksaw.
• Bolt Cutters: This is what I discovered that made short work of the bead cables.
• Drill and general purpose drill bits: Trying to punch a hole through the tire is a bit of a pain. I recommend drilling holes instead. Remember to select an over-sized bit for your wholes since the tire material will flex around your bit.
• Clamps: Various types and shapes. Just handy to have for when you are attaching your tire parts to other things.
• Grinder or Grinding wheel: Handy to help smooth out the rough edges of the bead cables.
• Metal File: If you don't have a grinder, you can just use a general purpose metal file to do the job.
• Sheet metal snips: I used this to trim out parts of the tire's sidewall after I did my initial cuts. Any heavy duty leather scissors will work to. You can probably use a utility blade as well.
• Wrenches / Ratchet: For whatever size nuts and bolts you end up using.
• Sharpie: Good for marking holes and laying out cuts.
• Nuts, Bolts, Washers: Hardware to attach your tire to your shoulder pads or whatever else you are basing it on.
• Chain and other 'bits': All sort of things you can attach to your armor to make it look more ad-hoc and lively.
• Safety Equipment! No joke. I got some basic safety glasses, and some leather work gloves. If you feel the need to hold the tire with your feet while cutting, make sure you are wearing adequate protection (aka steel-toed work boots).