Tire help

15s are about the only good 'spare track tire', per se. You can get a good drag slick on those, that has good sidewall flex. Now, if you want to stick with a drag radial, which I wouln't bother on an extra set, then you can squeeze a 275/40/17 on that 8" rim. It looks sweet, but doesn't offer hardly any sidewall flex, being stretched on the rim. It does however give you a nice footprint. I'd try some Nitto 555rs, or some BFG DR's. You can stick with the 245, and get a bit of flex at low pressure, but I've had some good luck with my old setup, that being the 275s on the 8".