So why 175/65R15??

Shorter tires also mean smaller frontal area.

Discount Tires, and possibly other tire sties, will list plus zero tires for a car. These are narrower or wider tires that should fit the rim while staying close to the OEM size diameter.

Aside: weren't the OEM Goodyears for the gen2 non-LLR?

 

Longer braking distance as well.

 

I drive a prius
I don't need long braking distance

 

A good way to keep track of speed with non OEM sized tires is GPS.

We put 205/55 16s on our second gen and it did improve the handling. The car was definitely improved going down a straight highway... more linear. MPG calculations have to be made fill up to fill up and then you need to add the extra percentage of miles that the odometer doesn't report due to the larger diameter. It will only be a couple of miles every 100 or so. But that does make a little difference in the calculation, since a tank full can take you 500 miles or more.

Properly inflated, the larger wheel and tire didn't impact my MPG results... but I'm pretty patient when I drive and tend not to come to a stop very often.

LLR tire that's light and a lighter wheel would be one of the best things we could add to the Prius. Hopefully there will be some light wheel options available for the c by the time it hits the market.

The Prius c is going to fly out the dealer doors, now that oil companies must be taking down their refineries to do "maintenance" and fuel blend changes as is usual this time of year... consequently nudging gasoline prices upward?:nono: Unbelievable.

 

I'm getting the premium package here in Canada which upgrades the tires to P195/50R16. Does this mean I will get worse fuel economy than the standard 15" tires? What about comfort and road noise?

 

A couple of the car magazines have reported that the Prius C has much tighter turning circle with the 15" wheel/tires compared to the 16" wheel/tire combos. MotorTrend found the turning radius of the 15" wheels to be 31.4ft and the 16" wheels a whopping 37.4ft! Anyone care to enlighten me on why a slightly wider tire would make such a huge difference in turning circle?

 

Might be a stupid question but why are bigger tires equated with better performance, or more $$$?

 

In theory yes. More contact area between tire and pavement means more friction which means it takes more energy to turn the wheel. This energy is provided by gasoline.

Larger wheels allow you to use tires with less sidewall (while maintaining the oem outside tire diameter) which translates into faster steering response and better handling. This works up to a point and after that the gains in handling performance stop and may reverse.

 

Tires aren't the only difference. The 16" wheels also come with EPS, which may not turn in as tight. Or the steering rack is just adjusted to keep the wider tires from rubbing on something while turning.

In terms of diameter, the tires aren't bigger. The rims are, which means the tire's sidewalls are shorter. These sidewalls are stiffer and will experience less deflection(bending) during a turn than the taller stock tires. So you can take turns more agressively. Wider tires can also have a larger contact patch for better traction.

As to cost, the larger rim and wider tire both require more materials. Then performance enhancements can carry a premium.

 

Wy care about turning? cornering? handling?
the car drives perfect OEM.
those things only matter if your racing.....and you don't do that on a public road.

 

I disagree with regards to the GenIi and GenIII. The car handles horribly even for non-racing situations. The oem tire setup requires you to slow down much more than I would like when navigating curves. Thankfully there are suspension mods that enhance handling such that you can keep the oem tire setup and thus maintain great gas mileage yet stil corner decently well. There is still no comparison to a set of 17" or 18" wheels.

 

The 16" tires are .79" wider and the 16" wheels are a full inch wider (allowing the sidewall to spread further out as well). All the C models have EPS. Presumably the steering rack on the 16" models is set up to allow less travel to avoid rubbing from the wider tire/wheel combo.


ron

 

well I don't agree 8FL
firts time I drove a prius on the highway I was also thinking ..Mmmmmm lots of crosswind
but the same car a few years later I don't have the problem..I am used to it that I don't even care
I also think its a good thing that handling if the car make you slow down. its saver.

 

Slowing down is safer but if you have to perform emergency accident avoidance maneuver's then the horrible handling of the factory Prius raises its ugly head.

I'm giving you a hard time.

 

no ;-) no hard time ;-)

I just drive normal
( you maybe say slow ;-) )
so my speed is that low handling is not a problem ;-)

 

But how does the car know it has 16" wheels/tires installed? I believe 15" wheel/tires are stock on all trim levels.

 

Trim level four comes with 16" wheels.

The car doesnt know what wheels it has. The steering ratio is set up differently from the factory. At least that's how it works for the GenIII lift back model Five.

 

There is a different steering rack when you buy 16" tires from toyota. This both is faster - fewer turns of the steering wheel - and more restrictive of steering angle. I do not know why it restricts angle so much, but it seems more restrictive than the tire size would need. In the honda fit for example, the turning radius is the same for 15s or 16s, but the 16s come with a suspension upgrade.

 

None of the trim levels come standard with 16's. The IV comes with the 15" alloys and the 16's are a factory option that includes the different steering rack.

M guess is that it has to do with how much is shoehorned into the front bay of the C, resulting in reduced fender well room and suspension clearance.


ron