17" wheels - effect on mpg ?

The tires you choose for that 17" wheel are going to be the biggest determining factor in the MPG hit. Many GenII owners have tested this out and the mileage hit can be quite significant. I regularly lose approx. 4mpg by swapping from my stock 15" wheels and Nokian i3 tires to my 17" Centerline wheels with 215/45/17 Kumho ASX tires.

Moral of the story: If you change from your LRR factory 17" to a more performance oriented tire expect your mpg to drop even further.

 

The 18"s on my Gen III reduced my mpg from 47-48 on average to 42-43...kind of a lot, but then again, they're much heavier than expensive 17's, but they were under $900 wheels and tires, so that factors in... they feel heavier, but they hug the road like glue. i can RIP around tight turns and my wheels don't even squeal much.



ok so reading back through this thread there seems to be some debate on whether or not theres ANY effect of 17's vs. stock 15's?.....its not simply size, but more importantly, weight. spinning 45lbs of wheel/tire up to speed and keeping it at a speed is MUCH more taxing on an engine than spinning a lighter wheel. also, WHERE the weight is matters. if the weight is concentrated towards the center (as in a 15" stock wheel/tire) its much easier to spin than that same exact weight spread farther out (a 17" wheel of the same weight would be more difficult for a engine to turn than the 15"). a good example of this is a figure skater, how slowly they spin when their arms are out, compared to when they pull in their arms in. so going up in size makes an engine work harder to move the weight, even if on a scale, the 15" and 17" weighed the same.

 

Glad you asked: I have a 2012 Prius 3...I literally just yesterday bought 15-inch rims and tires to switch from brand new 3 months old 17 inch rims and tires,(Prius 17 inch 5 spoke rims) with Toyo tires 17" 215/45/17. The performance was terrible. The car would sway back and forth as though I were driving a Mack truck with 50-inch rims. And all of this with a Tanabe strut bar, TRD rear sway bar, Cusco front under mount brace, Cusco mid-body under mount brace and TRD lowering springs made specifically for Prius. Yesterday I installed new 15 inch Motegi rims (16 pounds each: weight does matter) with Michelin 205/60 R15 Defender tires. (these tires are 1 measurement wider than prius stock tires and 1 measurement lower) The ride is great now. Keep in mind, the Prius' that comes stock with these 17 inch rims MUST have an enhancement somewhere in the suspension. Because my car was so unstable that I was willing to spend another $1000 on new rims and tires. I even took my car to a suspension specialist and he suggested I replace the rubber bushings with high-performance polyurethane bushing. Which I will do later to reduce play in the steering and get that quick handling response. Do what you want, but I'm a performance handling buff and I believe the Prius with stock 15 inch rims was not meant to handle the application and weight of a 17 inch rim and tire.

 

I think you're right, that there are some suspension differences with levels that come stock with the 17": For sure there's difference steering, bigger turning radius, that's documented. Somewhere...

Bottom line: it's better going from (stock) 17 to 15, then the other way.

Every winter I go from our (stock) 17 to 15's for snow tires, no problems.

 

I've got two stories about changing wheel sizes..... AND tire diameters.
Story 1) Had a Dodge Caliber which had a CVT transmission. Switched from 205/70/15 inch wheel/tires to 225/60(?)/17 inch wheel/tires....& promptly lost 2% to 3% MPG. With the standard wheels/tires, CVT was programmed to give its best MPG at 2000rpm & with gentle acceleration, would adhere closely to 2000rpm. Once it reached 60mph, the CVT then would begin increasing in rpms. Now with the larger diameter tires, the CVT would keep 2000 rpms till ~ 65mph AND then rpms would begin climbing. It would seem that any MPG increase due to lower rpms could only occur when I was over 65mph..... of which I very seldom was in that speed range. Of course, all the MPG decreasing reasons were active below 65mph, like heavier, larger diameter, & wider wheels/tires.
Story 2) Had (& have) a 2008 Hyundai Accent with 5sp. manual transmission, which like many similar era small cars, had too many rpms at highway speeds. Switched to larger wheel/tires that dropped rpms at highway speeds AND all the way down to 35mph, where you needed to shift to lower gears. Above 35mph, the lower rpms are able to off-set the heavier, larger diameter & wider tires (& their mpg reducing effects) to deliver HIGHER MPG.

 

Shortest, story, ever. - Comic Book Guy (The Simpsons)

 

I have a '11 Level 5 with 17" wheels and I had a '10 Level 4 with 15".
I have been told by a friend that has both that the Level 5 has a quicker ration steering but heavier loads on the steering wheel and he doesn't like it because of that.

I love the Level 5 w/ATP and can't tell the difference bc it's been a long time since I had the '10 Level 4 !!
On the highway I don't have to touch the steering wheel much because of LKA. It's sort of like Auto Yaw Trim.
If there is a heavy crosswind the LKA will work against it for you. You only have to nudge the wheel a bit.

It would be interesting to find all the suspension/steering spec differences on the Level 5 !

 

Off topic, but I love it!
Ernest Hemingway got into a bet who could right the shortest story. His entry was 6 words!

For Sale.
Baby shoes.
Never used.

Has all the requirements: Beginning, middle and end. A sad ending....

 

The steering on the Level 5 with ATP is much heavier. I have a 2010 Level 5 with 17inch wheels and a 2015 Level 2 with the same 17" wheels. The 2010 drives much different compared to the 2015, even with the same wheels.

 

We test drove a 2010 level IV, then a few days later a level V, and soon thereafter bought the latter. I was much more comfortable with the level IV steering feel, seemed more planted/assured, hard to explain. Could be other factors, say being second drive, daylight (first test drive was night time), but yeah.

The only downside: parking lot maneuvers are a little trickier, with the greater turning radius.

(I've translated Canadian level names to US.)

 

I wonder how that is explained?
Even if the 'lock to lock' turns on the steering wheel are less on the V, (if it has a different rack ratio),
why did they make the turn limits less on the V if the same 17" wheels work on other levels without rubbing problems?

 

Yeah not sure; the stock tires are slightly wider, but really minor.

The published turning radius (in sales brochure?) is different, and in some more tech publications the lock-to-lock stats are different I believe.