A couple of things to consider in regards to tires, first learn how to read the tire date codes if you don’t know how, if tire expense is two great to replace all the tires at once start with the steer axle tires first for obvious reasons, then if your steer tires happen to be the youngest tires you have you can change out those for the oldest tires you have. Tires are like playing chess, what are you willing to loose, also consider collateral damage that could occur should you have a blow out, body damage, air bag damage, coach damage underneath, etc, etc…….
Keep the tires inflated to recommend pressure, try not to be driving when it’s hot out, if you have to drive in the heat slow down a bit or leave earlier in the day and bet the heat!
Not purchasing the tires you can’t afford in one shot my actually cost you more in the long run!
Also during your updating and repairs consider how much you’re really going to use the coach, maybe your tires are sufficient for the time being until you can change out all at once and then hit the road, lots of things to consider!
Jmo