I personally don’t see how the medium duty stuff is worth messing with. I’m not knocking what your doing I’m just trying to figure out how it is more cost effective vs class 8.
Your engine isn’t cheaper to rebuild, A gold kit from
Cat is 5-6k and IPD is more like $2500. 19.5’s don’t wear worth a damn and are probably some of the most expensive tires you can buy. (love how they look on a pickup though). Your fuel mileage isn’t a whole lot better than the average semi hauling the same weight, same driving rules ect. From where I’m sitting your limits seem to be greater than the benefits. I know I’m probably missing something but from your numbers your getting 8mpg hauling 1/2-1/3 the load as a 6mpg truck. So on a 1000mi trip he may burn $150 more in fuel but you have a lower paying load assuming your figuring it by weight or even piece count. I know the semi will have more tires but it’s a wash since the red truck i posted a pic of in the other thread just changed his drives after just under 300k miles, 19.5’s will never come close to getting that.