There is one thing I will add to this, but my thumbs don't have many rules, is a little deal about axle scrub. Going up to a triple axle you really want to watch getting into really tight turn arounds ecspecially loaded. Three axles really do not pivot very good on hard surfaces and also, be mindful of the tail swing. I have seen many near misses, and most of them have been at fuel pumps. Just use a little forward thinking. You will definitely like the tri running down the road, but not so much when it comes time to replace tires.