Wider tires improve Prius handling and looks

<div class='quotetop'>QUOTE(LowCO2 @ May 25 2006, 04:51 PM) [snapback]261064[/snapback]</div>

You are obviously not and Oprah fan, and from Chigago to.

 

Umm, PICTURES people, PICTURES!

 

<div class='quotetop'>QUOTE(nyprius @ May 24 2006, 06:40 PM) [snapback]260569[/snapback]</div>

From what I've heard, all cars come from the factory with the speedo calibrated slightly high as a margin for error (+/- 2-3%); likely for legal reasons.

If it indicated below the actual speed, then this would be potential for a lawsuit in the case of an accident. By calibrating it exactly on, this chance of this occuring is increased compared to building in a safety margin. Also consider that when going through radar traps, you are also not going as fast as you think.

The easiest way to test your calibration is to lock on Cruise Control on a flat road and use a GPS that is capable of indicating your current speed and compare.

Speaking of which, I should try this in my Prius and test it out myself!

- Kevin

 

<div class='quotetop'>QUOTE(priusenvy @ May 25 2006, 04:33 AM) [snapback]260820[/snapback]</div>

i introduced the length to show the difference in cm², that's all.

 

FWIW, here is a link to a tire size calculator that will help determine what the effects will be when changing tire size. Going from a 185/65/15 to a 195/60/15 results in a speedo reading 1% too fast, with a 60MPH reading really being 59.4MPH. Circumference goes from 76.9 to 76.1 and revolutions per mile from 824 to 833. I've driven plenty of "plus-sized" wheel/tire packages on cars and this small of a difference is not worth adjusting the speedo for, as it can easily be accounted for by the driver imo.
Tire Size Calculator link

 

<div class='quotetop'>QUOTE(Sarge @ May 28 2006, 08:05 PM) [snapback]262217[/snapback]</div>

If your speedometer is off by 3% high, then you'll have gone a bit less than 35k miles, when your odometer reads 36K, and you're out of warranty. Hmmm, suspicious.

 

<div class='quotetop'>QUOTE(idaten @ May 29 2006, 09:33 AM) [snapback]262384[/snapback]</div>

then sell the car at 34k...BTW has anyone gone to 16" rims? and do you have pics?

 

If you are interested I have a set of 17" Scion rims and Nexen N3000 17" Radials available for sale. The Nexen Radial tires are 215/45ZR17 91W. The tire are about and inch wider but are nearly identical in circumference to the stock Pirus tires. They give the car a much better performance feel especially in winter and do not need to be calibrated.

 

In Europe the Prius is delivered with 16 inch wheels.
Standard tire size is 195/55 R16. In The Netherlands the standard tire is the Michelin Premacy. It's a summer tire.
I ordered my Prius with Vredestein Quatrac 2 all season tires, size 205/55 R16.

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<div class='quotetop'>QUOTE(Sho-Bud @ May 29 2006, 05:58 PM) [snapback]262463[/snapback]</div>

Do you know the weight of those 16" rims? If you can check the specs there. I wonder how they are compare to the weight of our (US) rims.

Dennis

 

Well to make things more fun, I've decided to see about squeezing a set of 18" rims under my Prius. I have 17" Scion rims right now. An 18" wheel with 235/35 18 tires is almost exactly the same diameter as the stock setup. The tire calculators copute both as having 124 revs per mile. Now I need to see if they'll fit, especially after it's lowered a bit with the TRD Sportivo kit.

 

What effect does the increased tire size/width have on milage?
I would expect it to drop since there is slightly more contact surface and therefore slightly more resistance.

 

Before you change the tires, buy the body stiffening plate and install it. My 2006 I drove for a couple weeks over specific roads and turns. Then I installed the stiffening plate from BT and what a difference. No more leanining in turns, handles better on windy county roads and bumps.

Worth the Price at $160.00 To me the difference in the leaning was amazing. I can actually accelerate now through turns and off ramps.

 

<div class='quotetop'>QUOTE(BVISAILMAN @ May 30 2006, 01:30 PM) [snapback]262949[/snapback]</div>

To be fair, I can do exactly the same without the plate. I usually pull 50mph+ on a 30mph turn (in dry conditions), with and without OEM tires. Are you doing better?

 

I have been offered a free set of winter Studless tires in new condition - they are 195/R65 - 15. I do not know if my rims will support this size or if this will cause and handling/safety or speedo problems. Does anyone have any experience with this size?

Jef

 

<div class='quotetop'>QUOTE(fjef @ Jun 2 2006, 09:23 PM) [snapback]264954[/snapback]</div>

Tirerack.com will confirm that the US OEM 2004-6 rims will support 195/65-r15 tires. In another thread you'll find others who've used 205/60-15 tires successfully.

I think larger 195/65r15 tires might improve your speedometer accuracy. With most speedometers and odometers reading 1-2% fast on new (855 revolutions per mile) OEM tires and most 195-65-15 tires revolving 831 - 844 times per mile when new, your speedometer may read 0-2% slow on new 195/65-15 tires. Of course as the tires wear, gradually losing 1/2" in rolling diameter and gaining 2% in RPMile, your speedometer will read faster and more accurate, if you're using 195/65-15 tires. On worn 185/65-15 tires, your speedometer will become even less accurate.

I'd like to hear from others who have mounted 195/65-15 tires on their 2004-6 Prius.

-----

Sorry Jef I just reread your post and noticed that you're driving a 2001 Prius. Everything I said above only applied to a 2004-6 Prius. The original wheels on your 2001 Prius will not fit the 195/65r15 tires. I would not recommend installing them on your car using 15" wheels either. Your speedometer will read about 7-8% slower than you're travelling. More importantly the tires (being 1" wider and 2" larger in diameter) will likely scrub against the car when going over bumps and turning.

 

<div class='quotetop'>QUOTE(Sho-Bud @ May 29 2006, 11:58 PM) [snapback]262463[/snapback]</div>

I like these tires more and more. They are very quiet, comfortable, and it looks like they suck on the road. Braking, accelerating, cornering, it's awesom. I still ordered a BT stiffening plate, because the Prius doesn't like sidewind, I hope that the plate will improve that.