Bigger rims and their effect on fuel economy

Depending on the weight of the rims vs the tire weights you could improve economy/performance or decrease it based on your product selection. I would suggest staying within 1/10 of the original tire diameter regardless of whether or not you go up or down in rim size to retain the accuracy of the stock computer. Thinner sidewalls may also affect the ride of the car by making it harsher. They may also marginally improve the cornering characteristics of the vehicle.

 

Supposedly, Abe Lincoln was asked how long a man's legs should be, and he replied, "Long enough to reach the ground." In the same vein, I'd say the OEM rims are exactly the right size, because the tires just exactly reach the ground.

 

<div class='quotetop'>QUOTE(Soylent @ May 4 2006, 10:29 AM) [snapback]249800[/snapback]</div>

I have had 17's on my '04 since approximately the 5000 mile mark (now 49000). The wheels are 17x7 Konig Theory's with 215/40x17 Yokohama Avid H4S tires which have one of the highest wear ratings for a passenger tire (also equates to less rolling resistence). The biggest issue with 17/18" wheels that you should be aware of is the offset. Offset is the is where the flange of the wheel mates to the hub of the car (either inor out), I went with a larger offset making the stance wider, more stable. The only clearance issue I have had is with the left front (240 lb. driver) and the factory bra on. The wheel hits the snap that goes into the fenderwell if you take any steep driveway angles otherwise there have been no issues.

As far as effects on fuel economy goes, driving in a normal mode (the way that most hybrid drivers drive) I have been able to get close to the EPA mileage numbers up to about 65 mph, at speeds above that you will see a noticable decrease in you mileage depending on the type of terrain you drive in. For example, I do a large amount of highway driving between my home on the central California coast and Arizona. Driving with traffic down I5 to L.A. then I10 to Phoenix (most of the time traffic is running 75+) I will average 40 to 42 mpg (depending on whether I am by myself or have others in the car).

Now from a performance standpoint. One of my biggest complaints with the stock tires was hydroplaning at highway speeds in moderate rainfall. The Avid H4S tires by Yokohama have an agressive tread pattern that disapates water (even in the monsoonal rains in AZ) yet on dry pavement are quiet. I have been involved in racing for over 40 yrs so I do get the urge to drive it like a sports car sometimes and with just the tire/wheel change the improvement in handling is astounding from cornering to braking. I have even autocrossed the car (with 18" wheels).The dealership has had no issue with the larger wheels and the warranty.

Hope this helps from a 1st time poster.

 

<div class='quotetop'>QUOTE(Spotter16 @ Jul 12 2006, 11:05 PM) [snapback]285385[/snapback]</div>

Thanks! I just put 17in chrome wheels and 215 45R 17 Goodyear Responsedge tires on my 05 at 15900 miles. I put up with the little ugly wheels and the $50 Integrity tires as long as I could. In a few months I will comment on MPG.

The most noticiable difference is a stiffer ride. The 45R sidewalls are .5 inch shorter than the 65R on the originals. A half inch of air is a nice cushion. But the slight loss of ride confort is way more than made up by the handling especially in cornering at high speed on freeway interchanges. I can now make the turns I made with my Lexus at 50 MPH with the Prius. With the ugly little wheels and tires I had to slow down to 30 MPH and piss of the drivers behind me.

The 17 in chrome wheels like the shark antenna, and the PRIUS decals don't exactly make a swan out of an ugly duckling but at last my Prius doesn't look entirely homely any more.