Prius V considering swapping wheels for 15" or different 17" tires - Advice Appreciated

Good, you are smart to keep the 17s. :thumb: This may be a good opportunity for a test. Try to get some good mileage figures on each size, I don't think anyone has really done that yet. Most of us suspect that there is a 1 to 2 MPG difference in the two types of tires.

 

Right off the top of my head, a Honda Civic has 16 inch wheels and a 15 inch mini spare. I don't own one so I can't check the size of the tires that they have, but as an example (or three examples), I have three cars in my driveway. My Ford Thunderbird has 185/60/R16 spare and 235/50/R17 tires on the regular wheels. The diameter of the spare is about 1.5 inches smaller than the regular wheels. My Lexus GS has 225/50/R17 tires and a 155/70/17 spare. The difference is only a half inch.

More to the point, my Prius V has P215/45R17 tires on the wheels and carries a spare that is 135/80/16. The difference is obviously substantial but most of the tire size calculators don't go down to 135, but it is at least an inch in diameter difference.

None of these cars have had the original tire sizes changed. In fact, the sizes above are taken both off the sidewall and the placard in the door well.

Are you sure you aren't talking about the size of the wheel as opposed to the tire? Even there, as you can see, it is common for a car to have 17 inch wheels on the car and a 16 or even a 15 inch spare.

Some of the domestic cars I have owned have had ludicrously small spare tires. That is why they call those midget spares "donuts".

Perhaps I don't understand what you are trying to say, but to make the statement that you must have the same diameter tires on a spare is just flat out wrong. Even if you meant the same diameter wheel size, as you can see, it is common for there to be a one or two inch difference.

 

My BMW X5 came with a different size spare from the factory. Funny thing is the OEM tires are run-flat, then why the spare for extra weight

 

Give me the sizes of your other tires.

Prius 2010:

Spare tire: 135/80/16 = diameter = 24.50

17" rims: 215/45/17 = diameter = 24.56

15" rims: 195/65/15 = diameter = 24.92

Lexus GS:

225/50/17 = diameter = 25.82

155/70/17 = diameter = 25.50

Ford Thunderbird...maybe you're right, but does your T-bird have Traction control, VSC, or even ABS??

My point is that ALL modern cars with TC or VSC require the spare to have the same diameter (NOT rim size) as the other regular tires. Yes, you can get away with 0.5 in of diameter difference, but i have not seen more than that. Why? VSC and TC uses wheel speed differences to work.

 

As for the Honda Civic, it gets interesting.

A regular Civic in 2008 has a spare of 125/70/15, while stock size is 205/55/16. Difference is quite a bit in diameter...3 inces!!

However, a Civic Si has a spare of 135/80/16, while stock size is 215/45/17 or 215/40/18. Difference? 24.50 vs. 24.56 in. None basically.

My guess is that the regular Civic in 2008 did NOT come with ABS or VSC or TRAC. However, the Civic Si did come with ABS (VSC??)...and thus, Honda wisely made the spare equivalent size to the Si factory tires.

Another example? 2008 Toyota Sienna CE (std with VSC, TRAC, ABS:
spare = 155/80/17 = diameter = 26.76
tire = 215/65/16 = diameter = 26.94

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So, basically, it is UNWISE to upsize your factory tires without considering an upsizing of your spare as well to match. If you upsize by less than 0.5", then you should be OK. Do i recommend it? No. I don't need my brakes to be pulsating on one wheel because the car's computer think that my undersize spare is slipping on ice. Why risk it, right? I would stick with stock factory sizes if you don't plan on changing out the compact spare.

 

I just picked up my Prius on Saturday. I would be willing to consider a wheel swap.

-Sam in Kansas

 

I purchased a IV with the SRP that came with Yoko Avid 15s and drove with them for about 5 months. I swapped out to Scion tC rims with 215/45 17s running Yoko S32A (non-LRR tires) for about 4 months. I then switched back to the stock 15s, ran them for a month before switching to OEM Gen III 17s, still using the Yoko S32As. After a year ownership with the car, here are my MPG figures for each:
Stock - 50.6 MPG (with a high of 54.0)
tC 17s - 46.7 MPG (high of 47.7)
OEM 17s - 47.1 MPG (high of 48.1 so far)
I know the figures will probably be better with the OEM LRR 17 in tires, but I don't want to spend more money on tires right now to test my theory.
Pros of the 17s: better cornering, more stability(less wandering) at higher speeds, looks.
Cons of the 17s: choppy and harsher ride, more road noise (quite a loud droan), decreased mileage, and cost of replacement
Pros of the 15s: better mileage, less road noise, quicker response to acceleration inputs which I think makes the Prius more fun to drive, cheaper to replace.
Cons of the 15s: iffy handling (especially with tires overinflated - watch out for ruts in the road) and more wandering at higher speeds, less "sporty" look (that's just my opinion).

 

I bet LRR tires will narrow the mpg hit to 1-2, consistent with what's reported. The very slightly worse mpg of the tC 17s is probably due to the less aerodynamic design of the rims compared to OEM 17s, as they're both heavy wheels.

 

booo!

I'd gladly take a road trip and pay you to swap my 15's for your 17s!!! :rockon:

 

The diameter on the rim might be different, but you are right that the overall diameter has to be close to the stock tire/rim. Even the 15" and 17" cars have similar diameter on their tires (25.4 vs 24.8 or something).

Try that on an AWD car or cars with LSD, I can tell you diff won't like life

 

I have a Prius II that came with the 15" wheels/tires. After a year, I replaced them with 17" aftermarket ICW Racing wheels and the Bridgestone Turanza 215/45R17 OE tires (picture attached)...10 lbs heavier tire/wheel combination. Not sure what the OE combo weight is but since I used the OE tire, probably not much. Saw a drop of about 2-3 MPG.

I agree with HI MPG's assessment of the diff between them. Frankly, the 15" Yoko Avid S33's were pretty noisy with a high whine...the 17" are about the same but with a lower tone...remember, they have a higher contact patch with the road.

15 - better MPG, better acceleration, smother (but "squishy" in my opinion
17 - better handling (no question harder ride), MUCH better looks (why I did it)...I have had a number of people from 18-80 years old come up unsolicited and tell me how great it looks...and they like the bike rack too!

Re the bike rack...drops 6-8 MPG...oh well, the price of biking!

Wheels are available on Tirebuyer.com for about $115 each...full disclosure, I work for the company that owns the website.

 

Robby - You're relatively close to me. I just have my 15" stockies in my closet if you want to try them on your car to see if you like them.

 

charlotteprius, nice rims!

 

THANKS! I really have enjoyed them and the unsolicited comments let me know that others do to. After I got the rims and rack, my college/high school age kids told me I was now "legit". As a friend of mine said "Price of rims/tires, $XXXX. Having your kids say you are 'legit', priceless!"

 

I am picky with rims...yours are very nice.

 

I just unmounted the OEM 17" wheel with factory Toyo tire. Put it on the scale. It weight 44 lbs each.

 

Well, if we had the Michelin OEM tire, then the tire itself weighs 21-22 lbs. Not sure how much the Toyo OEM weighs, but my guess is that it is about the same. So, the OEM 17" rim weighs about 22-23 lbs. The OEM rims are not the lightest, but they are not as heavy as some thought either.

 

I have a 'V' w/ 25,000 miles on it. My son has a 'III' w/ 50,000 on his. I would not trade my wheels/tires for the 15" stock for all the tea in China. The big foorprint does loose a little in the gas mileage dept., but in the road holding, and the holding on-center steering dept. (w/ electric steering), the differenmce is night and day (not to mention better traction on ice and snow).

 

Would 16" wheels/tires be a compromise? I don't see anyone mention that size. Could they fit on a V?