actually a larger with rim does offer some better performance. there is less sidewall deflection in the tire giving better grip and handling on the road. This is why the Sahara and the Rubicon has the same outside diameter but a different inside diameter. now obviously the increase in side wall size is better for off road and that is what the Rubicon was design for. But a lager sidewall is not the best for on the road and the Sahara package is put together for people that would prefer this.

There is probably a formula they use. If a outside diameter of a tire is X then a rim size should be Y. This is why the Sport has 16" rims. The tires are so small that a 16" rim would give it the best on road performance. You probably wouldn't notice a difference going from a 18 to a 17 but lets say one person has a 35 tire with a 15 rim and the other person had 35 with a 18 rim. If everything else was the same you probably notice a difference.

 

Umm, we're talking about a stock Jeep Wrangler (or I was, at least), not a sports car whipping around corners. I doubt you would feel any difference between a stock 32" tire wrapped around an 18" rim on a sahara or 17" rim on a rubicon.

 

Umm, really we are not talking about sport car? Oh maybe I was trying to answer the question on why they put 18s on the Sahara...

You know I should have wrote uou probably wouldn't notice a difference going from a 18 to a 17. Oh wait, I did.

 

What brand?

 

Exactly. Smaller wheels generally = cheaper tires. I downgraded from Rubi 17" to 16" ProComps. I save an average of $50 per tire from this decision. I'm on my 3rd set of 35's now, so this savings is becoming substantial. On the flip side, I'd love to add the new Baer Brakes 6-piston caliper kit..... but they require 17" minimum rims. This is the tradeoff.

 

18 inches aint bad baw but I always preferred the Moabs over the gladiators