Could someone quickly measure the diameter of the Viper tire?

[Vip-RT10]

On a 17 inch rim, the diameter for both the tire and rim (275-40-17) is 26 inches. Sorry, I have a '93 with 17 inch rims. Hopefully someone will measure theirs for you.

 

[SoCal Craig]

Try this site.
http://www.tolan-hoechst.com/cars/tirecalc.htm

 

[Marv S]

For 18" Pilot Sports:

25.7" Front

26.1" Rear

http://www.michelin-us.com/us/eng/tire/catalog/docs/doc_pilotsport.pdf