Cummins12V98 wrote:
DrewE wrote:
For most class C's, adding 5 psi to the rear tires over the chassis manufacturer's recommendations (i.e. the door sticker) will put the tires exactly 5 psi over their maximum inflation pressure. The rear axle weight rating is the maximum for the standard tires at their maximum pressure of 80 psi. It's fairly likely the wheels are also rated for a maximum of 80 psi.
Would 5 psi higher than the rating be dangerous in practice? Probably not...but still it's hardly a good idea.
Please show me a class C rear tire inflation of 80psi. Do you understand that will add up to at least 11,000#.
Like I said weigh your rig LOADED. Use chart, it ain’t gonna be 80psi front or rear.
I run full rear axle rating of 9,750#. Ram says 65psi rear.
Standard tires on the E450 (and, I believe, the E350) are load range E LT225/75R16 tires, which are rated for 2470 pounds each at 80 psi maximum for duallies. GAWR for the rear axle on the E450 is 9600 pounds, very close to the 9880 pound maximum possible with the tires. At any rate, 80 psi is almost always the placarded tire inflation pressure for class C motorhomes on the E450 chassis (and I believe the equivalent Chevy van chassis is similar in this regard).
The E350 chassis uses the same tire size but has a 8500 pound axle rating, so would presumably call for a somewhat lower pressure. I think the E450 is more common for class C motorhomes--and required essential for larger ones, of course.
Class C's based on the transit and sprinter chassis (and Ram ProMaster), as well as super-C's, do have different tire sizes and ratings and inflation pressures.
