That depends on the model of tire you wish to install. Look up the manufacturer's reccomendation. They usually list the range of rim widths in the Size & Pricing chart. The widest KDW2 you should install is 275 according to the BFGoodrich site.

And remember that WITHIN that range, the narrower tire will have less sidewall flex resulting in better steering response while the widest tire will have a wider contact patch.