Can you increase mileage with wheels?

You already know the answer. Leave well enough alone or , could be a costly mistake

 

Making safe wheels light weight is not a cheap business. For $400 a wheel I can find 8.7 pound wheels in 15 by 6.5j.
I do not think the lugs are right for a Prius, that may be a custom order.
SSR Wheels Wheel Lineup

It would improve braking, handling, performance, and ride. It might improve MPG if for no other reason than your wallet being $1600 lighter.

 

Toyota has done a good job fitting the Prius with high mileage wheels. Only problem, they're so UGLY. My PIP's higher mileage wheels are stacked in the garage. Go ahead, penalize me. My PIP with Prius 5 wheels, looks FAST and FUEL EFFICIENT, sitting still. Enough said.

 

Enkei RFP1's in 15" I would think are lighter than the stockers.

 

Yes but you won't like it:

• decrease the revolutions per mile of the front wheels and/or tires

I did this with my NHW11 (2003) Prius by using a larger diameter tire, ~905 revs/mile to ~850 revs/mile. This has the same effect as increasing the gear ratio, permanent 'over drive.' But there are a few drawbacks:

1. MPH indicator reads lower than true speed - this can be handle by figuring the calibration offset and mentally calculating the true speed. Easier, just to a GPS speedometer.
2. Miles indicator reads lower than true - so the distance traveled will be off by the calibration offset.
3. MPG indicator read lower than true - because the distance traveled measured by wheel rotations is off, the car displayed MPG will show lower than true. Just calculate the true MPG at the pump with the corrected distance.

I went with larger diameter tires because it also improves straight-line stability. The older, 2001-03 Prius is steering neutral and almost no tracking ability even with 'perfect' four-wheel alignment. But the larger diameter, slightly heavier tires have improved highway tracking making the car less fidgety.

The MPG improvement is slight but evident after doing the calculations. It also reduces maximum acceleration, permanent overdrive.

Bob Wilson

 

Reducing Unsprung weight is the holy grail of car racing. Light wheels, brakes, & Springs will improve preformance & MPG. It will also lighten your walet for quicker acceleration & breaking. Do you really need 2-4 more MPG and at what cost? Are you Autocrossing it at SCCA events? Entered in the Green Grand Prix at Watkins Glen?
If yes then lighten it up. My guess is that you can drop 10lbs per corner for a total of 40lbs before you attack the intake, header, & exhaust for another 40-50lbs.

 

Yea I don't like the RFP1's either, but as far as weight and cost goes its hard to beat them. I'm personally looking at the Motegi SP10's in 17". But its not a concern for me to lose a few mpg in the process.

 

Sure they have, IF they went from the oem 17" down to a 16" or 15". Going from a 15" oem to a lighter 15" may net a small gain, but whatever you spend on wheels will buy you a lot of gas.

 

Not worth it.

That being said, I can't wait to put my 17's back on. My snow tires in a 15" along with cold temperatures has taken my average from 52.X to 44.X.

 

^ Funny, our snows are 195/65R15 (Michelin X-ICE) and stock is 215/45R17 (Michelin Pilot), and they seem very close for mileage. Considering the 15" OD is bigger, the snows might even be better, since the odometer is off a bit with the snows, underestimating distance travelled.

 

I wanted the Michelin X Ice's but got too good of a deal on the Firestone Winterforces....It's like a tractor tire - loud and obnoxious, fuel consumption took a huge hit but wow are they amazing in the snow.

I have a set of Michelins that are going on the 17's instead of the OEM Toyo's in 3-4 weeks and getting put back on the car.

 

In theory yes. In practice no.

It's too expensive to justify. Not only do you need a very lightweight wheel but it must be aerodynamic as well (including a high offset). Most of the really light wheels appear to have horrible aerodynamic properties. What you gain from weight loss you lose in aerodynamics AND for the price difference you could purchase a lot of fuel. No one I know of has reported any quantifiable gains from lighter wheels. You're better off replacing your OE tires with something more fuel efficient and possibly taller when the time comes.

 

Yes, we have for our racers.
First, unless you want to race, lighter wheels aren't worth the cost. You can use TireRack to seach the weights of wheels that fit the prissy (mostly Honda Fit and older Hondas) but the cost is high. Some wheels, as low nice person 9 lb cosdt $200 or more each. The RPF1's that weigh 9.5 lb are abot $135 each. There are wheels that are wider as well but usually don't save weight. Honda Insight, gen 1's, use a 10 lb wheel often available in salvage yards.
And wheels with lesser offset, such as Scions, are advantageous in cornering but hard to save weight with wider rims
Second, if you want to see higher mpg you should select tires of the less weight. Again use TireRack to search tire weights. The energy required to turn wheels with heavy tires far greater penalizes mpg than heavier wheels. Physics of torque applies.
Most tires 175/65x15 or 195/55x16 weigh from 15 to 22 lb and yes generally the more narrow tire of similar overall diameter weigh less. If you choose to put wider tires you need to reduce diameter slightly to not play havoc with your mpg. For those of us who want our Prissy to convert into a 48 mpg sportster with lowered springs (not over 1.5" unledss you want handling diofficulties), shocks, and Dirzza ll tires, the 195/55x15 are a gift.
Third, increasing tire diameter by wheels or tires is another losing effort except on flat level ground.The Prissy does not benefit from a reduction in axle ratio in thr real world; not enough horsepower to utilize and thus adds power required.

 

Yes, we have for our racers.
First, unless you want to race, lighter wheels aren't worth the cost. You can use TireRack to seach the weights of wheels that fit the prissy (mostly Honda Fit and older Hondas) but the cost is high. Some wheels, as low nice person 9 lb cosdt $200 or more each. The RPF1's that weigh 9.5 lb are abot $135 each. There are wheels that are wider as well but usually don't save weight. Honda Insight, gen 1's, use a 10 lb wheel often available in salvage yards.
And wheels with lesser offset, such as Scions, are advantageous in cornering but hard to save weight with wider rims
Second, if you want to see higher mpg you should select tires of the less weight. Again use TireRack to search tire weights. The energy required to turn wheels with heavy tires far greater penalizes mpg than heavier wheels. Physics of torque applies.
Most tires 175/65x15 or 195/55x16 weigh from 15 to 22 lb and yes generally the more narrow tire of similar overall diameter weigh less. If you choose to put wider tires you need to reduce diameter slightly to not play havoc with your mpg. For those of us who want our Prissy to convert into a 48 mpg sportster with lowered springs (not over 1.5" unledss you want handling diofficulties), shocks, and Dirzza ll tires, the 195/55x15 are a gift.
Third, increasing tire diameter, by wheels or tires, isn't effective for anything but flat level roads. Prissys just don't have enough power to prevent the consideralbe extra power required to prevent less mpg in thed real world.