Hi!
Your tires WILL explode/go on fire

I use a fire wheell in some shows similar to what you're describing except with four wicks.
The heat build up in the rim is extreme, too hot to touch, I've got the scars to prove it.
I suspect that you don't actuatly want your inflatable rubber tires to explode and cover you and the audience with melted rubber?

MissEgyptology has the right idea, use some cool looking lights in between the spokes, possibly on sliders so that you'l get elipses at slow speeds and circles when you'r going fast.
Good luck!