Originally Posted by barryhiram

It’s all about liability ladies & gents……..Federal Motor Vehicle Safety Standards require vehicle manufactures to document capacities to the end user (us) at time of first sale. Exceeding any of these capacities will 1) Potentially cause vehicle failure putting consumer at risk of injury and/or death, 2) Void manufactures warranty.

I have a little experience with what’s going on here, in my industry, modifying vehicles for people with disabilities. We are required to document all changes made to any vehicle. NHTSA has approve a Make Inoperative form for our industry which are exemptions that allow certain changes to be made to a vehicle that may or may not affect crash testing certification by manufactures. Some examples are removal of airbags, removal of safety equipment, installation of hand controls, and drive by wire (electronic) driving equipment to allow somebody with a disability to drive a vehicle.

Looking at your driver’s door you will notice VIN tag, it documents Vehicle Identification Number, GVWR (Gross Vehicle Weight Rating) is the maximum amount of weight vehicle is designed to carry……….actual weight of vehicle (full of fluids), all occupants, and cargo. GAWR, Gross Axle Weight Rating front and rear, is maximum allowable weight for front and rear axles. Additional information is also documented e.i. rim and tire size, but not going to elaborate on those at this point. All of these capacities have been designed and engineered to allow for safe operation.

Attachment 191490


Next, Tire Placard on driver side “B” pillar. Manufactures were required by law to add label in 2006, label documents seating capacity, load carrying capacity, tire/rim size, and tire inflation.

Attachment 191491

So how is load carrying capacity calculated? Manufacture simply scales vehicle (weigh) to achieve actual weight (curb weight). Subtract GVWR from Curb weight = Load Carrying Capacity, this is the maximum amount of weight of occupants and cargo that can be added without over rating vehicle. Looking at Tire Placard (highlighted by red arrow) you will notice capacity is noted.

Originally Posted by CG_Pilot

Fantastic info @Berry hiram !

Would changing from the stock passenger rated tires to say “D” rated KO2’s change the GAWR and thus increase the safe cargo capacity?