What 15 inch tire will fit on a 6 inch wide wheel

[Bearcamp]

I have a set on Cady wire wheels and they are 6" wide. What 15" tire (as wide as possible) wil fit it okay? I also need to be around 30 dia. I was looking at the 255/70R15 and the 255/75R15. The 75 is higher. I need as wide as I can put on.

 

[Blue Eyed Devil]

L78-15

 

[sneakysnake]

This comes in handy for sizing tires.

http://www.discounttire.com/dtcs/infoTireMath.dos