Tires on my dolly are like the ones on the DP. They age out before they wear out. Saving fuel?, thats probably wrong but it sounds good. I have seen 2 Smarts being towed 4 down and should have took a closer look. We bought a Honda C RV new in 2017 and got a front wheel drive only so we could tow it on the dolly. Got caught in a bad snow storm in North East PA and the front wheel drive did just fine. I also bought a Featherlite trailer so I can take my F-150 if I want or anything else for that matter. We all tow what we think is best for us so just be happy if it satisfies you.