Yup it is a cost/profit/ride/other stuff thing.
The larger wheels mean a different more expensive gear ratio, it also means the rig rolls a bit easier, the tires cost more but wear longer, and you get more sidewall meaning softer ride and they can hold up more coach (Weight).
The smaller tires cost less but wear faster so the factory makes more money but you spend about the same over all. In theory.
I like the larger tires.. WHY.. Well on my Damon Intruder with 22.5's if work needs to be done under the rig, Like lub jobs and such,,,, I do not need to heed the warnign about not getting under the rig when it's up on jacks.
I don't need jacks
There is enough clearance for my 300+ pounds to crawl around under there all day with the jacks fully retracted and/or stowed (Depending on the jack) and the full weight of the coach on the tires. So there is absolutely no way for it to fall off the jack.
