I've shied away from this topic since the first batch of lift kits was sold back in 2020. Customers would frequently call or write in, head over heels in love with their newfound height after getting their lift installed. This part never really came as much of a surprise to me, although it never failed to put a smile on my face hearing others share in my joy of the oddity that is lifting a Prius.
What did come as a surprise was having that statement frequently being followed up with "and my fuel economy went up too!" After the first few times this happened, I simply chalked it up to a fluke, but as this continued month after month and year after year, I eventually had to accept that despite not being able to come up with a solid scientific explanation for it, it was much more than just an occasional anomaly.
What did come as a surprise was having that statement frequently being followed up with "and my fuel economy went up too!" After the first few times this happened, I simply chalked it up to a fluke, but as this continued month after month and year after year, I eventually had to accept that despite not being able to come up with a solid scientific explanation for it, it was much more than just an occasional anomaly.
Not wanting to sound like a snake oil salesman, I've always chosen to keep this tidbit of information to myself or those close enough to me not to think I was simply trying to push a product. I take a lot of pride in the products I produce, and I take just as much pride in letting those products speak for and sell themselves. After all, a good product will sell itself, and that theory has proven quite true for Prius Offroad over all these years.
Though I haven't been able to reach a definitive answer, I have been able to take note of the occurrences and find a bit of a pattern to them. This can be broken down into three separate categories: Lift, lift with HD rear springs, and skid plate. And of course, the subsequent mixture and combination of these three parts together.
Lift: For those that had the lift alone installed, improvements averaged anywhere from 0.5 mpg to 2 mpg. My theory here all hinges around momentum. The Prius is an inherently low vehicle with the ground clearance and approach angle of an exotic sports car...without being exotic or sporty. By increasing both the ground clearance and approach angle, you're forced to slow down less for things like speed bumps, driveway approaches, or imperfections in the roads. This, in turn, translates to being able to maintain more momentum, therefore using less energy, which means using less fuel.
Lift and HD rear springs: For those that had the lift and HD rear springs installed, improvements averaged anywhere from 0.5 mpg to 3 mpg.When designing our HD rear springs, I wanted to optimize ride characteristics with both an empty car and loaded down with 200 pounds of weight hanging off an added trailer hitch. In order to accomplish this, I would need to have the rear sit approximately 1/4"-1/2" higher in the rear when unloaded so as to maintain the factory "stance" or "rake" as much as possible when weight was added. By raising the rear of the vehicle slightly more than the front of the vehicle, it also changes the angle at which the car pierces through the presenting wind while driving. Think of it like holding your hand out the window as you're driving down the freeway. Adjusting the angle of attack with your hand even just a degree or two can mean the difference between cutting through the air like knife or the wind catching it and hurling it at the ground or the sky. The same goes for your car, only on a massive scale comparatively. That .5" difference in height translates to a big change in aerodynamics and very well might mean cutting through the air more efficiently.
Skid plate: For those that had the skid plate installed, improvements averaged anywhere from 0.5 mpg to 1.5 mpg.This one proved to be a little easier to rationalize than the others. More often than not, the flimsy plastic skid plate/splash guard/splash shield from the factory gets torn up over the years of catching on parking curbs, speed bumps, and driveway approaches making it hang down from the vehicle. This iin turn increases the surface area beneath the car and creates more air turbulence for the air traveling beneath the vehicle at speed. Next time you're on the freeway and behind a Prius, glance beneath it, and chances are you'll notice the black plastic skid plate flapping in the wind like a bedsheet left out on a close line in a hurricane. Our skid plates not only hug tighter to the vehicle by nearly an inch, but they are also incredibly smooth, which in turn smooths out the air pouring off them beneath the vehicle at speed. Less surface area, less turbulent air, less resistance equals more efficiency.
Between these three things, it's not unheard of to see mpg increases in the 3-5 mpg range. But here is where things get a little convoluted. Many customers primary purpose for the lift is to fit larger tires. Or if this isn't the case they are so happy with the increase in height from the lift that they immediately want to put larger tires on as well in order to gain even more height and improved handling characteristics. With bigger tires comes worse fuel economy and many don't give themselves enough time to actually notice the increase in fuel economy from the lift and instead see a reduction to their economy. Keep in mind larger tires almost always mean more weight, more weight means more energy required to get them moving and keep them moving, more energy means more fuel, more fuel equals worse mpg. (We cover this more in-depth in the tires article further down in the blog as well as the FAQ page.) My suggestion is not to rush into getting new tires right off the bat and enjoy the lift without the reduction in fuel economy and the cost of new tires for as long as you can. Then, once your tires wear out and once you've gotten accustomed to the lift and have a better idea of what your wants and needs are, research what tires best suit your needs specifically while sacrificing as little fuel economy as possible.