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15'' vs.17"

Discussion in 'Gen III 2010+ Prius Fuel Economy' started by Caug1, May 10, 2011.

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  1. Caug1

    Caug1 Member

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    Hello,
    What wheel should get you better mpgs?
    15'' obviously lighter so should get better mpgs, correct?
    Did any body test them?
    Thanks,
    C
  2. F8L

    F8L Protecting Habitat & AG Lands

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    The 15" wheel will. The wheels and especially the tires are generally lighter and there are more options for LRR tires in the 15" size.

    The 17" wheels generally use a wider tire which will increase road friction and frontal area (increased coefficient drag).
  3. Caug1

    Caug1 Member

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    Cool.
    Sounds like 17'' wheels would get less mpgs.
    I wonder if Toyota tested 15''vs17''
    I am sure 51- 48 was achieved with 15'' and not 17'' wheels.
    with research i did,
    stock 15''x6 are16.3 lbs with 18 Yokohama @18lbs.=34.3lbs
    I was looking at 16'' x7 wheels @ 13.7lbs and tires @ 20lbs =33.7, not much gain.
    i was hopping stock 15'' set up would be heavier.
    will stick with stock with better lrr tire. :(
    C
  4. dustoff003

    dustoff003 Blizzard Brigade #003

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    I have a V/Five with the factory 17 inch wheels and non LRR tires in 8,300 miles I have not went below 50 MPG yet. My average MPG is right around 53 MPG over the 8,300 miles and that is with E10 gasoline. I my driving style varies but tends to be more conservative, but I am by no means a hypermiler. I also have mostly left the car in ECO mode.


    Posted from my iPhone via the Tapatalk app.
  5. stream

    stream Senior Member

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    Yes they have, and published the results in the UK tech spec doc. It's a few MPG less for the 17" wheels--can't remember the exact number, but I've posted it in several other threads on this subject, so you can do a search if you're interested.
  6. oldasdust

    oldasdust Member

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    Also called unsprung weight you want to lessen the weight at all 4 corners if possible.ie tire and rim weight.
  7. Caug1

    Caug1 Member

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    yah i know about unsprung weight. every pound you save x3. so if i save 5 lbs on each wheel x3=15,x4=60lbs. take that of the wight of the car. better braking, better exceleration.
    looks liked 17'' lose mpgs.
    thanks,
    c
  8. Much More Better

    Much More Better Active Member

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    I doubt you'll push your Prius hard enough to feel the difference. That's like saying a skinny driver has an advantage over a fatter dude. Seriously, you're not racing. You might save 18 sec off a lap at Nurburgring. Just get some nice rims and enjoy them!
  9. xs650

    xs650 Senior Member

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    Unsprung mass (weight) has no more effect on acceleration than sprung weight.

    Rotating mass does have more effect that non rotating mass. But, the most effect extra rotating mass on a wheel can have is 2X and that is only if it is all located at the outer periphery of the tire.
  10. SuperchargedMR2

    SuperchargedMR2 Diehard Rams Fan

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    There are some very light 17" wheels. I've been looking for one that I like that is a 17x7. The narrower wheel will also save some weight. I'm also going to use a 205/50R17 tire so it won't be much wider then the stock 195/65R15 tire but still maintain the same diameter. Now just to find a wheel that I really want. :D
  11. bawzp9

    bawzp9 Caries eliminator

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    Does anyone Have runflats? Mine came with them. . .
  12. kormaster

    kormaster Junior Member

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    17 will be heavier but always looks better than 15s. To be, OEM 15s look too wimpy... i hope to change mine to 16 or 17s...

    MPG -> how much are you really going to save? I would say negligible to the point where you will not see your bank account get drained from the gas pump.

    In fact, you will notice your bank account go down when you buy new 17s with new tires :D
  13. dustoff003

    dustoff003 Blizzard Brigade #003

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    Really?? What make model and size tire is it?? Sure your not thinking LRR's are run flats?


    Posted from my iPhone via the Tapatalk app.
  14. F8L

    F8L Protecting Habitat & AG Lands

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    Actually, you can feel the difference even with mild acceleration. I notice a huge difference every time I swap my 15s for the 17s and I have lightweight wheels. The tire weight difference alone is enough to feel the difference. We won't even go into the reduction in gliding. :(
  15. F8L

    F8L Protecting Habitat & AG Lands

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    Running 17s on my car costs an extra $133 (at $3/ga) per year in fuel. Tires cost an extra $200 but that is spread out over 2-3yrs.

    I'm hoping the next tires I purchase will reduce my 4-6mpg loss down to 1-2mpg loss.
  16. Thai

    Thai Prius Neophyte

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    This is from a different thread:

    Let's say you drive 12,000 miles a year.

    Prius V/Five gets 48 mpg..............Prius II gets 52 mpg (hypothetical numbers to show 4 mpg difference...UK data shows the difference is actually around 1-2 mpg...but, i am exaggerating here to emphasize my point)

    After 12,000 miles, Prius V uses 250 gallons of gas.

    After 12,000 miles, Prius II uses 230.7 gallons of gas

    Difference = 19.3 gallons

    Prices for regular gasoline = $3.90 per gallon (picking a random dollar value to be in between today's gas prices and next few months')

    So, after 12,000 miles, the driver of Prius II saves $75.27 vs. Prius V driver. Now, this is after 12,000 miles, which is a year's driving for most people. If you drive less, then the savings will be much less...if you drive more, then a few more pennies are wasted.

    Now, tires for 17" rims are more expensive...but, the newer ones that are coming out have good mileage rating.

    The benefits of 17" rimmed Prius outweigh the disadvantages IMO:
    1. Better looks
    2. Sportier steering and ride/handling
    3. Rear wheel well insulation for quieter ride
    4. Unique suspension components (shocks and springs are unique to V/Five)
  17. F8L

    F8L Protecting Habitat & AG Lands

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    You are making too many assumptions based on one test done in the UK.

    The average loss for most people upgrading to a 17" wheel is between 4mpg and 6mpg. There are reports of 2mpg losses but I question their testing methods considering they are using high performance tires. With LRR 17" tires (which just came out) I think a 2-mpg loss is totally realistic and I plan to test this next month when I switch from Kumho ecsta ASX to Michelin Primacy MXM4s.
  18. Thai

    Thai Prius Neophyte

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    That is why my calculations use 4 mpg difference. But, compared to my brother's Prius IV, i am about 2 mpg down from him. The point is that with high mileage cars, a difference of 2-6 mpg is insignificant...you can easily make that up by skipping one McDonald trip per month! :D (Of course, this will lead to weight loss...and thus more fuel savings!!!)
  19. F8L

    F8L Protecting Habitat & AG Lands

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    I agree completely. The difference even at 6mpg is pretty darn small. I also agree that swapping to 17s or 18s makes a huge difference in the fun-factor of the car although some may not like the ride characteristics of a low profile tire and those who like to hypermile will be disappointed in the reduced mpg and gliding ability.
  20. bawzp9

    bawzp9 Caries eliminator

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    They are Goodyear runflats. I have no spare. Correct size.
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