size rim, wheel weight, tire spec vs fuel efficiency

Bob Wilson

 

Factory 15" wheel and tire setup will give you the best fuel mileage. I have the 17" Toyota five spoke wheels with non LRR tires and I'm sure I get a little less fuel mileage. Exactly what, I'm not sure and with my Prius providing excellent fuel mileage, it's no big deal. I like the 17" wheels for the look and the slight fuel mileage loss is worth the better looking wheels. As Bob shows, higher speeds have a greater effect on MPG reduction.

 

You need to get responses from those who've had both, and can post their relative mileage. There are so many variables affecting fuel usage, that individual experiences will be misleading.

 

I go from Michelin Pilot 215/45R17 on OEM 5 spoke alloy rims, to Michelin X-Ice2 195/65R15 on Corolla steel rims, with no noticeable change in mpg. Guess that means the Pilots on the the porky OEM rims are about the same as snows, lol.

The OEM rims I've guestimated around 24 lbs. This was by weighing the tire/rim assembly (with decent digital luggage scale) and deducting tire's spec'd weight.

The Corolla steel rims and tires are significantly lighter, just judging from what my back tells me, when I put them on. The OEM assembly weighs maybe 10 pounds more than the snow package? I should weigh both sets, next time I get the chance.

 

The weight is effectively irrelevant in the case of the Prius. Wheel size, however, isn't. To make your request much simpler just assume you will average 45-50mpg on 17" wheels with LRR tires and 50-55mpg on 15" tires. The error of margin is +- 2mpg. Most people lose 4-6mpg with 17" or larger wheels. Wheel Weight doesn't seem to matter although lighter is better for overall performance.

 

Yup.

The mpg losses are found in the hysteresis of the tires. 17" tires are less efficient and in most cases wider so you get an aerodynamic hit as well.

The problem is finding wheels that are cool looking, affordable and only weight 11lbs. Because 17" tires are generally 3-4lbs heavier than 15" tires, you will need to find a super lightweight 17" to compensate for heavier tires. Unfortunately, people have tried super expensive 15" wheels and noticed no significant gain in fuel economy over the OE 15" wheels.

If you could build a custom 17" wheel with a narrow width and produce a LRR tire to fit it then you can overcome all these losses. I believe BMW did this with the i3 and their 19" or 20" wheels. Hard to say for sure since they can't run a 15" wheel and their wheels won't fit a Prius. A quick test swap would be cool.

 

Hi Mendel, what year of Corolla wheels work with Gen 3 Prius?

Are the steel Corolla wheels less weight than the steel Prius wheels?