In addition to dual spacing clearance between the tires when loaded, changing tire sizes also results in changes to final drive ratio gearing, affecting acceleration, shift points, and gradeability in a given gear.
Still, I've read several stories (not sure if they are all from the same member or from several members) over the years on RV.net of Ford Class C owners changing to 215/85R16 (which actually results in more clearance between the duals).
Moreover, I've also read of at least one member who upsized to 235/85R16, as that was the tire size that Ford used on their SRW E series vans in the late '80's and early '90's.
I think that these owners were looking for a bit more ground clearance. They might have been looking for more weight capacity across the back axle too. I didn't pay much attention to the details when I stumbled across their posts, figuring that a keyword search would always retrieve their reasoning and results, whenever life presented a "need to know" demand.
Well, I was shocked at how sparsely few results revealed themselves in search, so I was hoping a fresh topic would unearth the considerations and motivations of E-350 and E-450 based Class C owners who have changed their OEM tire size.
Thank you for your words of caution on dually spacing.
