Ya, i'd start with a bigger tire, so that you dont have to load as much weight in it. Im currently using a standard size car tire (bout 16") and I put a 45 in it for longer distance work, and pu to 130lbs for shorter pulls. And thats all my weight, so im needing to get a bigger heavier tire sometime soon.
Depending on your ground surface, it can be VERY tough to pull a tire. My neighborhood has asphalt with gravel embedded in it, so there is a TON of friction.
Here is my recommendation to making a tire. Get an SUV tire, or possibly a semi-truck sized tire if your really strong. (You should not have to pay for either, a tire shop will give you old ones.) Drill TWO holes in the tread on opposite ends of the tire. (If the tire was earth these would be the north and south pole) But they need to be pretty much exactly opposite ends. Pick up 2 eyebolts, 4 washers, and 2 nuts. The rest you should be able to figure out. You can use tow strap or some rope, and some caribeners, or some kind of way to connect everything. Also, if you want to challenge your grip more, making some handles out of 1.5-2" PVC makes it brutal.
Thats it really. It takes about 15-20 minutes to make and then you can get to pulling. Having the eyebolts on opposite ends is nice, because when you pull to one end of the street, you can simply flip around to the other side and pull the other way. Otherwise you have to turn the tire each trip.