Handling differences between 15" and 17" wheels

I have a Prius V, and got it because I wanted the 17" wheels (they handle better, and look better) and the LED headlights (had HIDs on my cars for the last 10+ years and didn't want to go back to dimmer halogens).

I went on 2 fairly long test drives--one in a Prius V, and one in a car with 15" wheels. There is a definite handling difference (which is attributable to the lower profile tires), and the steering is much more responsive (due the fact that the V has a more direct steering ratio).

Nobody buys a Prius expecting a sports car, but, from somebody who's owned lots of sports cars, I clearly felt the V had a more enjoyable driving experience.

 

It depends on how hard you want to sling the car around corners.

The 15" wheels are decent enough and with high enough tire pressure there is minimal tire rollover so cornering is ok. Body roll is more pronounced.

Thde 17" wheels will create more road noise in most cases, create a bumpier ride and the tires are more expensive to replace and there are not as many choices in low rolling resistance tires available. The upside is that they are a lot nicer looking and the car is more stable, less tire roll, and you can hit corners hotter than you normally can with the 15" tires (assuming same level of driving skill).

I swap between my 15" stock wheels with Nokian i3 tires and my 17" Centerline wheels with Kumho Ecsta ASX tires. I really cannot figure out which ones I like better. If the mielage was the same I'd choose the 17s but that mielage hit really gets my goat.

 

When I decided to get the V with 17" wheels, I was worried about the low profile tires being less comfortable, but after having the 2004 model, I wanted to make sure highway handling was a stable as possible. In actual practice, the suspension seems to have just the right amount of damping to make the low profile tires no problem. I even pumped them up to 42/41 psi. Definitely feel the road more, but I quickly got used to it. I don't know how the IV handles, but the V is pretty much on rails, has tight but light steering, and has very little body roll. I have a sunroof in my HyCam and only use it occasionally, so having one on the prius wasn't important to me. I also had some doubts about the durability of the solar panel and design of the moon roof. In short, even with an MPG hit, I have no regrets and would not want to switch.

 

I went from nice handling cars (with lousy FE) to a Camry Hybrid in 2007. I loved the FE but the soft mushy ride was only acceptable. I decided to go with the Prius V because I really don't want to compromise on handling any more than I have to and even if I only get 45 mpg, so what? That's still pretty incredible and the difference in 45 and 50 mpg is not significant enough for me to worry about.

 

2-3 mpg

 

One of the real pleasant surprises of my Prius V is how well it handles. My last 3 cars were all sports sedans, and although the V is far from a sports sedan, the handling is great.

As for the MPG hit with the V, I think it is too early to quantify. I've had the car for a week and on my daily commute to work, I'm getting ~65 MPG consistently. I think the MPG you get will have more to do with how you drive the car and the terrain of your commute than what tires are on the car.

 

We have owned our new 2010 Prius V with Nav. for 10 days. We had a 2005 Prius to compare against. There is no comparison. The new V drives like on rails and take corners more like a sport car(Wehave had both 2 camaro's and a GT Mustang). We wondered about how it would ride with thr low profile tires, but it rides very well and is very comfortible. We also wondered about how much mpg we would loose going to the low profile 17 inch wheels. On the same trip we traveled with our 2005 many time to our lake home we have been able to get about the same mpg with our new V that is not broke in yet. The first tank we got 51mpg. The second tank so far we are at 56.5 and our overall for the two tanks(820 miles) is 53.2. So, we feel that if we gave up 2mpg for the 17's, the improvement in handling was more than worth it. Hope that hbelps you.

 

I got the base pkg. knowing that I'd be upgrading, but spending money the way I wanted to, on items I felt I absolutely need to further contribute to a fine and already very efficient vehicle.
I had the 15" wheels, and the tires were just ok. It is a bit weak around corners, and especially in any kind of quick lane change, or emergency manuvering. I went to my local Discount Tire shop, and we tried on a set of Bridgestone RE960 Pole Position(hi-perf. all season). That alone I thought did the trick enough where I felt safe, and the handling improved immensely, no more "mushy" ride. However, also keep in mind that Toyota Engineers carefully designed the entire Prius package to be efficient and everything working together. I've taken off one of my wheels/tire and weighted it. It came in @ 33.5 lbs. total. I know the tire on the EP20s is 19lbs, that leaves the stock 15" wheel at 14.5lbs. The 17 inch wheels I don't know how much it weighs, but has to be 2 or more lbs. heavier, and the tire + at least 1-2lbs. At that, you've already added a minimum of 3-4lbs to the unsprung weight at each corner of your car. I've tried it both ways. 15" stock wheels with upgraded tire, I took a 2-3 mpg hit maybe close to 4. This is over a period of 2K miles driving around city and hwy. In the next 1K miles, I used the 17 in. Racing superlight wheels @16 lbs. + Continental Extreme Contisport DWS @ 21lbs. With that I really didn't get any additional notice-able difference vs. the 15" Bridgestone RE960 from a performance or handling standpoint, but did notice now that the mileage is at least 4-5 mpg off from original stock tire/wheel pkg.
I was for the first 2000 miles getting avg. 52-55 easily. Now I'm not. So, before deciding to do too much with tire/wheel package, be very careful not to defeat the original purpose of a Prius. My V8 Super-charged AMG gets 9-17 mpg city/hwy, has 19 inch. 275 size tires, and is about as stable as can be. But on most days I'd rather be in a Prius putting around town saving money on GAS, and the environment. Hope this helps with your decision. On the Sunroof, I'd agree with many other respondants, it's nice to have, but for occassional use, I won't pay $3600 for it. I'd save that for future plug-in modification.

 

In power mode, I've tried, and by the way makes the car drive a lot better, more at ease in traffic, and not in the way of other motorists, I loose 5+ mpg, measured over multiple trips around town. If the trip is longer, the car has more time to make up for lost mileage to power. On short tirps it is close to 10mpg. I'm only getting 40mpg - 42mpg on short runs under 6 miles.

 

the 15inch give more comfort. the 17 inch are more sporty and less comfort to my expirence

 

Picked up a 2010 V with Nav, Blizzard Pearl, a few days ago. We still have a 2006 as well so I have an easy test capability for the two wheel sizes. First, I think the 2010 exceeds anything I imagined in terms of looks. Pictures just don't do it justice, especially with the 17 inch wheels. There is a clear difference in handling, with the 2010 tighter and more responsive, but I happen to like the "floating" feeling of the 2006 as well, so it's a "difference" not necessarily one being better than the other. I have the 2006 at 40/38, and we are getting 51mpg in the Spring/Summer with no special driving effort. It's too early to even know what my MPG is on the 2010, and I would appreciate any suggestions on tire pressure for the 17 inch wheels. It is, however, an awesome looking car and drives wonderfully, so I don't think you can go wrong with the V!

 

Don't forget you can buy aftermarket 17" rims and tires for ~$1000 that will be lighter and therefore more fuel efficient than the stock ones. Slap those on your III or IV with solar and you have the best of both worlds.

 

That is not an apples to apples comparision. You cannot compare a GenIII with 17s to a GenII with 15s. It is a totally different car.

 

Why is everyone hung up on the weight of the wheels?
I believe it is the rolling resistance of the 17 inch tyres that causes the higher fuel consumption, not the weight increase. Remembering the 17 inch wheels are fitted with wider tyres and one would expect 17 tyres to have stickier tread compound than the less sporting 15 inch tyres. I think wheel weight has a very minor impact on consumption.

 

I don't think that is correct Pat. Unsprung weight does have a large impact and the amount of energy required to spin the wheels. We learn this detail pretty fast in the racing world and the physics apply here just as well. I do agree with you that rolling resistance is a huge factor but I wouldn't discount the wheel weight though.

The larger diameter wheels place more of the wheel/tire mass further away from the hub (axis of rotation) which causes the engine to work harder to spin the entire mass of the wheel. So even with a set of 17"s that weigh the same as a 15" set there should be losses due to the outward shifting of the mass of the wheel. Now throw on a set of 17" that weight 8+lbs more than the 15"s and you really should have a measurable difference in energy output required to spin the wheel/tire and thus a loss of efficiency.

To test this out for yourself tie a lead weight or a tool or whatever to a short piece of rope (3') then swing it around you. Now tie the same object to a 10' rope and swing it around you. Notice it takes more effort the get the object rotating than it did with the 3' rope.

Here is a better write up on the effects of unsprung rotational mass on the HRE Wheels website.

Rotational Inertia’s Effect on Performance

 

I was thinking about this too. Has anyone checked the rolling circumference, etc., of the aftermarket rim and tires against the spare tire dimensions in case it needs to be used?

 

But once up to speed that energy is stored in the wheel and will assist to keep the car coasting wont it? Will the flywheel afect stabilise speed? This is something I noticed with my bicycle when I fitted alloy rims in place of steel rims, I could feel more of a pulse when pedaling but overall it made little difference to how exhausted I was at the end of the ride. I changed nothing but the rims, tyres remained the same.