Yea, just one tire mounted under there improves the drive and helps if it gets slimy. I did that to get the tires off the floor and out of the way. Can't imagine running that way, -I don't suggest it lol. - Hit a chuck hole, and your spares just may head for hills. Or cause someone to have a very bad day.

 

I suppose if you were high enough off the axles you could.

 

Dual spares For The Win lol