Sprinter-Sportsmobile tire pressure specs
We took delivery of our Sprinter-Sportsmobile about 5-6 weeks ago at SMB North. I have a question about the tire pressure recommendations for the vehicle. The van is a 3500 long wheel base extended body with the 11,030 GVWR. The Sportsmobile build is the EB110S with some modifications (no propane, no generator, extra alternator and no solar panels, are the big ones). According to SMB North, the build weighed in at 8213 lbs. The M-B tire pressure specs are 61 psi at all positions for both unladen and laden vehicles. The label affixed by SMB calls for 47 psi in the front tires and 70 psi in the rears. The M-B specs list the GAWR as Front= 4,410 lbs; Rear= 7,720 lbs. As a long time trailer camper, I have a copy of the tire pressure/load specs for a wide range of tires. According to the specs for the M-B tires (LT 215/85 R16 115/112Q Load Range E), the 61 PSI recommended by M-B is more than sufficient in the rear duals to significantly exceed the rear axle rating. OTOH, even 61 psi in the front tires is somewhat short of the front axle rating. I suppose putting 70 psi in the rears might improve the stability of the rear, considering there is some high mounted weight (cabinets and roof A/C), but I don't get the point of 47 psi in the front. I did not check the tire pressure until recently. I had my local M-B dealer install a dually tire valve kit and checked the tire pressure a few days later to ensure that all was well (BTW, the Tire-man dually kit seems to work quite nicely). They had inflated the tires to 61 psi each. The van seems to handle OK with the 61 psi. Does anyone have any insight into what is the source of the SMB tire pressure recommendations? (I have a call into Nancy at SMB, but she was out today).