j-d wrote:
... So you're shopping for LT225/75R16E ...
BTW, LT215/85R16E tire size is OK too. They have the same load carrying spec ("Load Range E" is "Load Range E"), but have a slightly larger diameter for improved ground clearance and maybe slightly improved gas mileage due to making the vehicle's overall gear ratio a bit taller.
I recently put six(6) new Michelin LTX215/8516E M&S2 tires (plus the spare) on our Class C and they have so far been superb. I hope and trust that the sidewall cracking will no longer occur. I use 303 on them just in case because the tire covers are a hassle (started to move the RV in the back yard twice in the past without removing the covers and hence tore them up!).
IMHO, sidewall cracking is much more related to the excessive heat generated from sidewall flexing on the highway while traveling with slightly too-low inflation pressures per the weight they're carrying (this is regardless of weight chart numbers because weight charts are not concerned with maintaining a tire's shape under load). I have noticed that big rig tires never seem to have any apparent bulging in their sidewalls when you take a look at their tires at rest stops because ... they are fully inflated at high pressures so as to keep their shape to provide minimum flexing regardless of load.
Even though I have a small Class C that nicely underloads it's Load Range E tires, I still keep the rear tire pressures at their maximum Load Range E rating of 80 lbs.. This makes the ride in the rear stiffer but minimizes heat generation in the sidewalls. Also, since a 215 tire is slightly narrower than a 225 tire, there is better air circulation between the individual tires in rear dual sets for further improvement in removal of the heat resulting from sidewall flexing.
BTW, with 80 lbs. pressure in the rear duals, Michelin's new M&S2 sidewall material still does manage to somehow improve the ride a bit in the rear of our Class C. My future addition of Koni FSD shocks in the rear should help even more.
