1. Attachments are working again! Check out this thread for more details and to report any other bugs.

What size tires to get?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by CoolWind, Dec 14, 2004.

  1. CoolWind

    CoolWind New Member

    Joined:
    Oct 18, 2004
    19
    0
    0
    Location:
    Hillsboro, Oregon
    Hi Folks - I am considering purchasing 16 inch wheels and higher-quality tires for my Prius. However, I'm a bit confused as to the tire size I should get. Here are the facts as best as I've been able to compile them:

    The Prius in the US is delivered with 185-65-R15 tires.

    Tire rack offers 15" and 16" tire/wheel combos for the Prius, and when I select 16x7" wheels, the TireRack configurator suggests 195/55/16 for tire size.

    However, my dealer's parts expert is suggesting 205/45/16's for the same wheels. Says his supplier recommends them on the basis that 205/45 will be more accurate in total diameter against the stock Prius wheels.

    Is this true? Does anyone know the math that can help me figure out which tires to buy: 195/55 or 205/45? Also, when going with 16x7" wheels, do I need to be concerned with 205's being TOO wide for the rims or the wheel wells?

    Happily, my dealer has agreed to mount, balance, and test for rubbing and clearance on the wheel/tire combo before binding me to purchasing them, but I'm still wondering which size would be best.

    Lastly, when I called today, the parts advisor told me his supplier was suggesting runflat tires only for the Prius. I did a double-take at this, since the stock Goodyear Integrity's are certainly NOT runflat, WHY would replacement tires have to be runflat? I wonder if this is simply their interpretation of the required load rating of the tire.

    So many questions - hopefully some knowledgeable person out there has an answer or two...
     
  2. tochatihu

    tochatihu Senior Member

    Joined:
    Apr 10, 2004
    9,045
    3,528
    0
    Location:
    Kunming Yunnan China
    Vehicle:
    2001 Prius
    Hey CoolWind, plug your options into this web site:

    http://www.1010tires.com/tiresizecalculator.asp

    And then you're the expert!

    One goal is to keep the same overall tire diameter (205/45/16 does not achieve this). Another is that all that wide rubber must fit into the wheel well for all sterring angles and suspension travel.

    Even though I have only the classic Prius, I doubt that 205 width tires are going to fit in the front.
     
  3. jamarimutt

    jamarimutt New Member

    Joined:
    May 4, 2004
    985
    5
    0
    You're going to spend a lot of money for new wheels and tires, and instead of obtaining a notable improvement in handling you'll most likely see a decrease in fuel economy. The stock wheels are made of aluminum for lighter weight and the stock tires are low rolling resistance and good for at least 40,000 miles. I would leave well enough alone and spend more wisely the money saved on gas.
     
  4. CoolWind

    CoolWind New Member

    Joined:
    Oct 18, 2004
    19
    0
    0
    Location:
    Hillsboro, Oregon
    tochatihu: Thanks for the link! That's exactly the calculator I needed! Using that link, I've gone back and compared the diameters, and 205/45 is almost 5% off the total diameter of the OEM wheel/tire - an unacceptable difference. 205/55 is closer (about 1.6% off). But alas, TireRack had it right - 195/55 is almost exactly the diameter of the OEM wheel.

    jamarimutt: Your point on fuel economy impact is noted. Does anyone know the weight of the OEM wheel? The replacement wheel I am looking at is 16.5lbs - so is very lightweight itself. I am not looking to be talked out of this purchase (I can do that myself :)), but info on HOW MUCH fuel economy impact to expect would be useful.

    Thanks for the advice!
     
  5. FredWB

    FredWB New Member

    Joined:
    Dec 1, 2003
    331
    5
    0
    Location:
    San Diego, Colli-fornya
    I did try the 195H60X15 tires, Michelin Hydroedge, and the mileage difference was about the same as the 185H65X15 Hydroedge that I ended up with after about a month with wider tires. I think the wider tires handled better and probably should have kept them. But I thought the 185's would be better on gas mileage. After all was said and done, I got about the same mpg's with the both sizes and very little difference from the Goodyears, maybe 1-2 mpg at the very most (if any at all). I have heard of others here that tried 195 or 205 size with other brands, like Bridgestone, claim a 15-20% drop.
     
  6. Tempus

    Tempus Senior Member

    Joined:
    Feb 17, 2004
    1,690
    6
    0
    Location:
    Washington DC
    Vehicle:
    2004 Prius
    As I recall the Prius Wheels are about 14 pounds (6.5 kg).

    They are also designed to have a very low mass on the outside of the rims to decrease inertia.
     
  7. CoolWind

    CoolWind New Member

    Joined:
    Oct 18, 2004
    19
    0
    0
    Location:
    Hillsboro, Oregon
    Thanks for all the advice. As it turns out, I have decided NOT to upgrade the wheels now, just the tires. The deciding factors for me were:

    1) the weight - even some of the high-end alloy wheels were at least 3lbs heavier than the OEM wheels, and higher-quality tires also add weight. In the end, I was not happy with the idea of the performance and mileage impact

    2) It's VERY HARD to find decent tires in the 195/55/16 size! I went back and forth with my parts dealer for many days, and racked my brain searching TireRack and the manufacturer's websites, but there are only a couple manufacturers that sell tires that size, and these tires have either poor to fair reviews (Dunlop 5000 - also expensive), or no reviews at all (Avon Tech M550 - new tire, little data).

    So, in the end, I decided on swapping the stock Goodyear Integrity's for Michelin HydroEdge in the same 185/65/15 size.

    Thanks again for the advice.
     
  8. allenlux

    allenlux Junior Member

    Joined:
    Oct 16, 2004
    20
    0
    0
    Location:
    Bofferdange, Luxembourg
    Just for the record, European Priuses - which all come with 16 inch wheels as standard - take 195/55R16 size tyres.

    I believe the standard OEM tyre is the Michelin Pilot Primacy.
     
  9. FredWB

    FredWB New Member

    Joined:
    Dec 1, 2003
    331
    5
    0
    Location:
    San Diego, Colli-fornya
    <div class='quotetop'>QUOTE(allenlux\";p=\"58375)</div>
    And according to an article I read, the std size in Australia is 195H60X15 and some type of Michelin too I think. In spite of the larger size, the article still mentioned some bad manners, wandering, at freeway speeds with cross winds.
     
  10. removeum

    removeum Member

    Joined:
    Jul 6, 2004
    407
    0
    0
    Location:
    El Paso, TX
    Vehicle:
    2007 Prius
    Model:
    II
    8) I changed my tire from the OEM’s to Goodyear Comfort Treads 185/65/15’s.

    Ben
     
  11. achuchra

    achuchra New Member

    Joined:
    Apr 8, 2006
    1
    0
    0
    Your dialogue was quite helpful, so I decided to share my 2006 Prius tire upgrade experience.
    I am pleased to report that the Falken ZE-512B 195/60/15 88H have greatly improved handling at the cost of 1-2 MPG at highway speeds. The Prius seems to be less affected by cross winds, but the tires did not solve the tendency to wander. This report is after 1K miles on the OEM tires and 1K on the Falkens.

    My Prius handling complaints included numb feedback, the lack of road grip, the car’s constant need of corrections to follow a line at highway speeds and particular squirrelyness when encountering cross-winds.
    I felt Toyota went too far in optimizing gas mileage (reducing load margins in the interest of less rotational intertia and minimal tire friction) compromising drivability. With the OEM GY Integrity 185/65/15 86S, the car felt like it was riding on over-inflated over-burdened balloons. I was willing to trade a couple of MPG in exchange for addressing the aforementioned woes. I sought a stiffer, better connected ride without excessive noise.

    After doing my research, (Tirerack site, Priuschat and CU) the Falken’s seemed to have the best compromise of (in order) wet handling and wet braking, rolling resistance, noise, steering feel, wear, price, tire weight and ride comfort. The runner up’s (not in any order) included Bridgestone Turanza LS-H, Bridgestone RE950 and G009, Michelin Energy MXV4, GY Assurance Triple Tred, Michelin X Radial DT, Yokohama Avid TRZ and Avid H4S, and Kumho ASX. I valued comparative test results much higher than survey’s.

    Riding on the Falken ZE-512B 195/60/15, the Prius feels much better connected and more capable in turns. The car plows less, much of the steering nebulousness is gone. Corrected measurements indicate a 1-2 MPG hit at highway speeds and no measured difference below 50MPH. I am happy to give up 1 MPG in combined driving in exchange for the handling improvements. The Falken’s are almost as quiet at the OEM GY’s with a subtle whir heard from 20-30 MPH. Wind and other noise obscures the whir by 35 MPH. For the record, the Prius is somewhat less affected by crosswinds, so the new rubber improved but did not completely solve that issue. The car still tends to want deviate from the selected line and needs too vigilant attention to maintain the desired path in both straights and turns. I suspect the cause lies somewhere between alignment, body flex, and aerodynamics.
     
  12. jbarnhart

    jbarnhart New Member

    Joined:
    Jan 3, 2004
    629
    1
    0
    Location:
    Santa Clara, CA
    BT Tech stiffening plate. It's not a placebo -- it's the real deal.
     
  13. Sho-Bud

    Sho-Bud Member

    Joined:
    Jan 5, 2006
    190
    0
    0
    Location:
    Amsterdam, Netherlands
    Vehicle:
    2006 Prius
    <div class='quotetop'>QUOTE(allenlux @ Dec 18 2004, 03:09 PM) [snapback]58375[/snapback]</div>
    Yep,
    But I ordered my Prius with All Season tires in the size 205/55 R 16. To be precise: Vredestein Quatrac 2.
    The Toyota dealer didn't see any problems so I guess this size will fit fine.
    I will know in a few weeks, the car is scheduled to arrive at the dealer on 21 april, than wait another week and a half before delivery.
     
  14. NuShrike

    NuShrike Active Member

    Joined:
    Feb 21, 2005
    1,378
    7
    0
    Vehicle:
    2005 Prius
    Model:
    Five
    I have Yokohama AVID H4Ss on at 195/60R15 which are only 2 pounds heavier per tire and a minor drop in road noise vs the Integrities. Tirerack says these are 855 revolutions so exactly the same as OEM.

    A few K miles broken in now and no mpg losses I can attribute beyond 1MPG, but vastly many times improvement in traction especially in rain.

    Had an incident where this large truck lost traction and swerved left and right over 3 lanes during some heavy SoCal rains directly in front of me in the carpool lane, while myself at the same speeds was gripping fine. Good thing the guy was able to not jack knife or flip, and only rubbed up against some Mercedes that decided it was a good idea to try to pass on the right.