One of the first questions we ask when a customer calls with question pertaining to ride quality is “What wheels & tires are on the truck and to what pressures are the tires inflated?” Why, you ask? Simply put, not all wheel/tire combinations are created equal. Load Ratings and pressures, number of plies, radial vs. bias, tread design (A/T, M/T, Highway), and profile all affect one’s ride quality; further, choosing a tire based on price and size alone won’t necessarily net a customer the proper tire for their application.
This guide will provide insight into the more important specifications assigned to a tire by the manufacture and to what heavy-duty truck owners should pay attention when selecting an aftermarket tire. There is an abundance of information on the web pertaining to each tire specification in as much detail as a person could want to read so we’re going to focus on load rating and tire pressure; the most important factors in our opinion.
Specific to heavy duty trucks, let’s take a look at the door tag on our 2012 Ram 2500 Megacab. It lists the stock Michelin’s Spec:
- Front: 265/70R17E as 5500 lbs total (2750 each tire) at 60 PSI.
- Rear: 265/70R17E is listed as 6010 lbs. (3005 each tire) at 70 PSI.
- Total Tire Capacity: 11,510lbs.
We drove our 2012 Ram 2500 Mega cab (6” Performance 2.65 kit and 37 inch Toyo M/T’s) to the scales to get actual weight. We found that with ¼ tank of fuel, normal cab clutter (2 car seats, kid’s toys, race radio) and a 37” spare, we weighed in at 8,480lbs. She’s no featherweight. Further detail revealed a front weight of 5200 lbs. and 3260 lbs. in the rear. This nets us a difference of 1,120lbs less than the GVWR.
The gross vehicle weight rating (GVWR) is the maximum operating weight of a vehicle as specified by the manufacturer including the vehicle’s chassis, body, engine, engine fluids, fuel, accessories, driver, passengers and cargo but excluding that of any trailers. Basically, the maximum weight the vehicle is built to withstand in bolt on accessories plus the load carried in the cab and bed combined. Below is a chart for our particular 2012 Mega Cab 4WD Truck.
So we’ve got a factory Tire capacity of 11,510 lbs. and Truck capacity of 9,600 lbs. We also see the axles are rated to handle the same load to the factory tires, 11,510lbs meaning they’re likely the limiting factor in the GAWR (Gross Axle Weight Rating). This means the GVWR is the true limiting factor to loading our truck, thus it’s the baseline against which we’ll compare the tires.
After purchasing a Carli Suspension, most customers purchase an aftermarket 35” or 37” tire, or a metric equivalent. These aftermarket, all terrain/mud terrain tires are often more robust in both sidewall and ply construction commensurate to their intended application leading to higher load capacities at lower pressures.
We’ve been through more than a few tires in search of the Holy Grail, do it all tire. For the sake of this article, we’ll compare two well regarded brands with which we have extensive experience, Toyo and Falken.
Toyo is our comfort zone; the bar against which all tires are measured. Becoming the Carli go-to tire without any working relationship between the two companies (we pay what you pay for Toyos) was not an easy feat. It took us years upon years of pounding tires everywhere from Southern California to the tip of Baja on the road and on the most rigorous dirt trails and yes, even cacti fields, for these tires to earn their reputation. The tires proved their merit again and again. We recently struck a deal with Falken Tire so a few of the shop rigs are now running the Wild-Peak A/T. The construction of the tire is pretty incredible. The weights and sidewall construction are on par with a Toyo M/T in their equivalent size. They’re D-Rated in the sizes we’re running and haven’t been subjected to near the abuse to which we’ve subjected the Toyo’s. Time will tell if they’re a contender but we thought they’d make a great comparison given they’re a D-Rated tire often recommended to the budget-minded consumer where the Toyo’s are the more expensive, E-Rated option.