First time we ran V-rated (149mph) Speed Rated Toyo Proxies, about 32" dia, and about 12" wide. These are OK to 200mph IIRC.
I sent one out Standard Testing Labs http://www.stllabs.com/testing.htm
and had them tested at 215mph. After 20 minutes, at 20% over full load, they had a minor failure, a "chunk" flew off, but the tire was intact. At a normal run time, at normal weight, 215mph should be no problem. IIRC, I told them 20 miles, but they did 20 minutes, or something like that.
HOWEVER, we also tested a "Y-Rated" tire (186mph factory supercar tire). It exploded in 7 miles, and I do mean exploded. WAY unsafe at 215 at truck weights.
The Toyo V-Rated worked well at both El Mirage and Bonneville, and were cheap.
To go over 200mph with a heavy vehicle (6000+ lb) you need to do your homework, or at least do some dyno testing.
We are now running Mickey Thompson Bonneville tires, 18" rim, 30" dia? Very expensive, almost no rubber on them.