With the cost of gasoline almost triple what it was just a short time ago, there have been a rash of folks freaking out about how crappy their Vanagon's MPG is. Many comments have come from our customers that have installed GoWesty 15” or 16” wheel packages, and/or have gone to a higher output GoWesty engine. Now they are second guessing the wisdom of making changes to their Vanagons that may have reduced the vehicle’s efficiency. Let me take the opportunity here to put these issues to rest.
Wheel and Tire Change
Changing from 14” wheels to either the GoWesty 15” or 16” wheel/tire package:
When this change is made, the odometer on your Vanagon started registering much more accurately than it did with your old 14"s. It is typical for the odometer on a Vanagon with 14” wheels to read anywhere from 4% to 8% TOO MUCH. With the GoWesty wheel package, it is reading about 0-2% TOO LOW. So, if you add up the worst case, you can attribute as much as 10% of the change between your old MPG and the new MPG to simply the change in the actual odometer reading. So, if with your old set-up you were able to get, say, 300 miles on a full tank (yeah, in your dreams!), now you get only 270. No, the vehicle is not getting worse mileage, the odometer is just reading more accurately. That is, you never really went 300 miles on that tank of gas, and you never really got 20+ MPG.
So what about the new tires? Aren’t they heavier and wider? Does that not cause more drag? This must cause a decrease in mileage, right? Answer: NO. First of all, the increase in weight is pretty negligible. We are talking maybe 20% more, max. Furthermore, whatever more the tire and wheel weighs makes them consume more energy when accelerated to speed. But once there, the energy is stored in the rotating assembly as kinetic energy and takes no more energy to maintain at a given speed. When climbing a hill, the energy stored is transferred back to the entire vehicle’s kinetic energy, and actually helps keep the vehicle moving, reducing what is needed from the engine. With respect to the width of the tire and whatever more aerodynamic drag they may create: Come on! We are talking about a brick on wheels here, after all. Compared to the poor coefficient of drag (CD) of the Vanagon’s shape, and its sheer size, the increase in air drag that the wider tires makes is totally negligible.
The fact about the switch to the our recommended tires is that there is no down side. We offer only the most cutting edge, longest lasting tires on the market, and there is just no way the change to a 15” or 16” tire from ANY 14” tire rated for a Vanagon can possibly cause a decrease in overall efficiency. None.