Toby, You did not say what brand dually you have and is it gas or diesel? as you know changing the tire size will also be the same as changing axle ratio so if you do not need the extra towing and clearence is no proble you should be ok. If it's a chevy diesel dually it will really affect towing. No they should not touch.
Toby, you should have no problems at all by going to the larger tires with the 454 and 4.56 axle ratio. Really though they came with the 225 or 235's although newer models did switch to the smaller tires. Could present somr problems in the computer as they are set for factory sized tires but I have never seen where it made that much difference. I would go with the 235. Son runs them on a 88 model dually with same engine and axle ratio and tows a 24 ft enclosed trailer with race car w/out any problem but, it is not computerized.