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How about a real thread about TIRES?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by fastlane, May 11, 2006.

  1. fastlane

    fastlane New Member

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    SO...

    I need to get some tires for my 2005 - 15 inch stock rims.

    The Integrity is one of the worst riding, squishy-soft sidewall havin', poor highway handlin' tires I've ever ridden. BUT they do return a decent result as far as fuel efficiency is concerned.

    As for my driving style, I drive VERY aggresively and I do it for about 1000 miles a week - lot's of freeway. Hard, fast cornering, aggressive surface street driving style. Think Mario Andretti but with 43mpg average. After about 3 million miles in Los Angeles, my motto is, "you're either in my way, or behind me..."

    Anyhow, anyone have any success finding a better freeway handling / cornering alternative to the integrity that doesn't destroy the fuel efficiency of this car?

    What tires have you tried?
    What results?
    How do you like them?

    Special focus is on good handling high mileage tires.

    Also any info on very poor results also invited.

    Cheers All and happy posting.
     
  2. benighted

    benighted New Member

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    Many here on PC will tell you to look at Michelin Hydroedge, Goodyear Tripletread or Goodyear Assurance Comfortread.

    I have Toyo Proxies TPT on mine and they made a very dramatic improvement. They are 'H' rated with nice thick sidewalls and I've noticed no loss of MPG as long as I keep them at 42/40PSI.

    You can browse the different tires availiable for your car at tirerack.com
     
  3. ggarb

    ggarb Member

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    <div class='quotetop'>QUOTE(fastlane @ May 10 2006, 10:16 PM) [snapback]253334[/snapback]</div>
    Good question.
    John1701a wrote about his handling and performance experience when he
    replaced his stock tires with Michelin Hydroedge.
    http://john1701a.com/prius/prius-maintain03.htm#Tires

    Has anybody found a better tire than the HydroEdge?
     
  4. fastlane

    fastlane New Member

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    Hmmmm.

    benighted,

    I too have been running my Integritys at about 40psi front and rear. However, I would prefer to not do this becuase the fact is that overinflating tires makes for a jarring and rough ride as well as poor handling and excessive tread wear. Tires are designed to be inflated to certain pressures. When you overinflate them, you change the shape of the intended footprint of the tire by rounding it out into a donut-like shape. This does provide a fuel efficiency advantage because the contact patch of the tire becomes smaller; only a narrow section in the center of the tread around the circumference of the tire. Trouble is tread patterns are not designed to work this way and the handling suffers greatly because of it. So I suppose I am also hoping to find a solution that doesn't involve grossly overinflating the tire to cheat the fuel consumption result. I would like to for once enjoy the intended traction and ride comfort of whatever tire i do finally decide on... without having to accept 38 mpg in order to do it.

    thoughts?

    by the way, if you doubt me about the effect overinflation has on the shape of the contact patch of the tire, try this. Go out to your car after you inflate the tires to, say, 42 psi - which is what 40psi becomes once your tires warm up from the friction created during freeway driving. Take a ruler and place in across the tread of the tire, from sidewall to sidewall. See how bowed the tread is? Now deflate the tire down to about 35 psi and check it again. This is how the tire is supposed to make contact with the ground. Full contact from side to side. Do you see? Overinflation not only compromises handling and comfort, but also safety by diminishing braking effectiveness and traction during emergency maneuvers. There must be a solution that doesn't involve so much compromise.

    happy motoring...
     
  5. ched1968

    ched1968 New Member

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    I still have the OEM tires on mine I always have my tires rotated/balance every 3,000 miles at America's tire Co. I got the lifeime service with them just for $45.00 which infact make a big difference even the dealer's service manager was impressed with the tire because they're all wear evenly. My ODO is now @ 28,750 I notice that they inflate my tires around 38/38 so the other day I tried to do the factory required which is 35/33 the car felt more comfortable and it feels cushiony on bumps but I felt the the car start out heavy...I'm going to the Shop tomorrow to replace all 4 tires. I'm going to put in Goodyear comforthreads, see how it does on the freeway grooves...maybe I will stick to the recommended psi since the manufacturer did test the EPA ratings base on the tires running on these psi, I'm no expert just my guess? :blink:
     
  6. Vincent

    Vincent Don't Wait Until Tomorrow

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    ched1968
    Not a very helpful response; what are you driving, where do you live.
    Please update you profile!
     
  7. amosd

    amosd New Member

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    I've been very happy with my BFG Traction TA's. I had to replace my stock Integritys at 37K due to a pothole that destroyed one and damaged another - they would have run for another 10K or so. I too looked over what's available on Tire Rack, and decided on the BFG's in stock size. They are T rated so are good for our Prius' top end. I've been very happy with them for the last 29k miles. They handle nicely, and since the weather has been warming up, my mileage has been steadily rising - my last tank was 55mpg. I have an 80 mile each way almost all highway commute to work. I'm sure the Goodyears lots are getting are good tires, but wanted to post a good alternative that's working for me.
     
  8. seasalsa

    seasalsa Active Member

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    <div class='quotetop'>QUOTE(fastlane @ May 11 2006, 12:52 AM) [snapback]253357[/snapback]</div>
    I doubt this! It was true with bias ply tires but not with steel belted radials. Most of us who run 42-40 have experienced greater wear on the outer edges which also goes against your logic.
     
  9. john1701a

    john1701a Prius Guru

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    <div class='quotetop'>QUOTE(fastlane @ May 11 2006, 02:52 AM) [snapback]253357[/snapback]</div>
    Wow! Talking about outdated information!!

    That may have been true back in the 20th, but certainly is not anymore.

    Today's tires offer dramatically better quality, providing a flat traction surface all the way up to the maximum listed on the sidewall. And after 37,600 miles of driving at that maximum with the better tires, I still have an even tread depth all the way across the tire.

    In other words, the term "overinflation" most definitely does not mean PSI cold-measured below the maximum.
     
  10. tochatihu

    tochatihu Senior Member

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    I definitely agree that we want full contact across the tread surface. In addition I want even wear of the tread from side to side, and have always supposed that those two goals would be achieved together, at some tire inflation pressure.

    I've made detailed tread depth measurements at about 4k miles over 87k miles in Prius. OEM Potenza tires, Goodyear Allegra, and now the initial 8k miles with Nokian i3. Their max sidewall inflation ratings were 51, 44 and 51 psi respectively. All did well at 42 psi front 40 psi rear, but I am still working out the best choice for the Nokians (now 48/45).

    It would surely be a coincidence if 42/40 worked best with all Prius replacement tires. I would start with 95% of the sidewall max in front and 90% in the rear. Use less if the ride is too rigid. Measure tread depths, and rotate them at least as frequently as Toyota recommends. You will find the best pressure for you. You *might* find a setting that leads to more tead wear in the center than the on the edges. But this would contradict my experience with various radial tires on Prius; thousands of individual tread depth measurements.

    A police officer posting with considerable "extreme" driving experience does not agree that my choices are the best for dry traction. I would really like to set up cones in a vacant parking lot sometime, and do some maneuvering speed vs psi tests. That project needs an organizer.

    Oh, it may seem like a lot to be into the 3rd set of tires at only 87k miles. I let 'em go when they still have 3.5 to 4 mm tread remaining. A German study found a rapid decrease in wet traction/braking distance increase just below that range.
     
  11. talonts

    talonts VFAQman

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    <div class='quotetop'>QUOTE(fastlane @ May 11 2006, 02:52 AM) [snapback]253357[/snapback]</div>
    If you think the OEMs are rough at 40, then you should stick with the OEMs, as any tire that is going to handle better will ride rougher. The OEMs have about the floppiest sidewalls of any tire I've ever run into.

    As for handling, you yourself note how floppy the OEMs are. Raising the pressure increases the handling (at least up to the ohS*** level), as the sidewall flex is minimized.

    And treadwear? Think again. Anyone I know that gets over 40K out of the OEMs does it by running at such "extreme" pressures as 44/42 - which is still within the tire's inflation range. The first set on my 04 lasted through 45K, and the edges of the tread were worn more than the center (which tracks with a lot of other "overinflators"), even with proper alignment.

    Have you done chalk tests on the OEMs? If you had, you'd see that the diff between the recommended 35/33 and running the max of 44/42 is near, if not at, zero. Putting a ruler on the tread anywhere but at the contact patch is a useless test. You are only concerned with the contact patch for treadwear.

    You're making the same mistakes/assumptions as others do as to assuming that Toyota picked those pressures for tire life, handling, etc. They picked those pressures for your butt, and to minimally cover rollover tests (see Ford and the SUV rollovers, where they reduced the recommended tire pressure to an unsafe level (at least as far as Firestone was concerned) simply to get them to pass rollover tests), and not much else.

    I'm starting to question whether you've actually experimented with any of this, regardless of your 3M miles of "experience".


    BTW, HydroEdges really don't ride that much rougher at 44/42 than at 35/33.
     
  12. 200Volts

    200Volts Member

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    Back to the topic.
    Bridgestone RE950 tires in stock size give my 04 blistering cornering and braking and rain performance. I can take a 2 lane 90 degree curve rated at 35 mph with a 60 mph entry and 55 mph exit speed. No need to "set" the car as much (ala rallly style swing before the turn).

    BUT, they ride very rough, even at 36/34 psi. Something in the Prius suspension is way too tight, I think to compensate for the terrible Integrities ( I think it's the struts, combined with sloppy bushings for the sway bar(s)=the quirky handling)
    Dirt cheap price, about $78 ea on sale.
    See my full review in the knowledge base, more then 30 days old.
    Winter mpg about 46, summer about 48 (was getting 52 with Integrities). 40k with each stock and 40k miles with RE950.
     
  13. fastlane

    fastlane New Member

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    In spite of what a couple of you are saying about the modern tire not deforming under over inflation, i tried this yesterday and saw it for myself.

    The whole story is that my local tire shop ordered the wrong tires for me yesterday and so i ended up with a set of the Dunlop SPort A2 Plus. He told me if I wasn't happy that he'd let me come in and exchange for something else after a couple of weeks if i wanted to. I have been buying tires from this guy for about 7 years so that helps.

    Anyways. I left the shop with the factory recommended 33rear 35front cold psi. I tried this out for about a 40 minute drive and saw such a dramatic drop in fuel efficiency that i decided to let the car cool and bump up tire pressure to 40/40 fornt & rear to see if i could improve things a bit. Other than the mpg, the tires felt fantastic and turned in/cornered VERY well actually.

    After pumping them back up I took her back out on the freeway for an evening apppointment and felt the jarring stiffness i was familiar with on the Integritys at 40psi. Although i did notice some improvement in fuel efficiency, I still wanted some better ride quality so I pulled into a gas station to bleed a bit of air back out.

    Before I bled the tires out, I decided to grab a three ring notebook from the car and run the side edge of it along the contact patch of the tire from sidewall to sidewall - as i described above - to check the profile of the overinflated tire. The tire was completely ballooned becuase of overinflation. This was actually why i wrote this into my previous post. This is not speculation, I SAW IT MYSELF.

    I then decided to check the pressure thinking perhpas i had grossly overinflated the tires due to a faulty gauge at the other gas station.

    No.

    Pressure was about 42/44 at highway temperatures - which is right where they should be if cold pressure was about 38/40. 44 is the max rated psi on the Dunlop Sport A2 Plus so they where still within spec . Which incidentally is a brand new model from a reputable company. If you talk to just about ANY tire guy, he'll tell you the same thing I am telling you now. Inflation pressure WILL effect the contact patch and wear patterns of a tire. Period.

    As far as outer edge wear we all experience with over inflation, this phenomenon is probably due to the soft sidewall of most of these energy efficient tires working in combination with the ballooned footprint. As the car is pushed into a turn, the sidewall "rolls" the tire over to the edge which files down the tread on the side of the tires more aggressively. I noticed the same wear on the outer edges of all four of my old tires. Most tire guys will also tell you that LOW pressures will also wear the outer edges of the tires more becuase the center of the tread footprint curves up away from the road when the tire is underinflated, forcing the tire to ride on its sidewalls more. For whatever that's worth.

    On another note. If you want a great handling tire that looks really bitchin', with less emphasis on fuel economy, the Dunlop SPort A2 Plus is a good bet. This is apparently not the same tire as the Sport A2 that many reviewers complained wore out too fast. The new PLUS model is supposed to address the subpar tread life of the former version of the tire while still offering AA road holding.

    Also, in all fairness the tires my shop put on are also 195/60 15 so they are a bit wider and heavier than the recommended 185/65 15 would be. No doubt this is costing be some mileage as well. I am wondering if i should just try the correct size of this same model or go to a safer bet... Trouble is I can't really "try" them. If i have my shop put them on, I would really be committing myself to that choice, which is a gamble on fuel efficiency. I can't very well just let him put another set of tires on for a week and then go back and swap 'em out again for free whenever i feel like it - even if he would be willing to accomodate me.

    I think that would just be rude and annoying.

    Does anyone have any experience with this Dunlop tire?
     
  14. john1701a

    john1701a Prius Guru

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    <div class='quotetop'>QUOTE(fastlane @ May 11 2006, 04:16 PM) [snapback]253718[/snapback]</div>
    Ok. So we will list that particular tire as a bad choice if you want to run higher PSI.

    It makes sense that some will work better than others. Those that report the tire remain consistent under pressure lucked out. They happened to choose a tire that did better.

    Tires require tradeoffs. If you want to favor one aspect, there is typically a penalty with another aspect.
     
  15. Tom_06

    Tom_06 Active Member

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    <div class='quotetop'>QUOTE(john1701a @ May 11 2006, 05:45 PM) [snapback]253734[/snapback]</div>
    Here's a tip on setting tire pressure for handling from an Audi forum. Will tell you what the pressure should be for handling, not fuel efficiency of tire life - all these things are a tradeoff.

    http://forums.audiworld.com/a6/msgs/53203.phtml

    - Tom
     
  16. ggarb

    ggarb Member

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    I have 29,000 miles on my 2004 Prius; for the first 10,000 miles I kept the tires
    at the factory 34/32 PSI. At my 10,000 mile service the Toyota dealer set my
    tires to 40/40, saying the factory now tells them to do that for better tire wear.

    My tires have worn down most of the tread at the curve where the sidewall
    becomes the bottom tread. I drive for fun, not trying to maximize MPG, so I
    accelerate into curving freeway extrance ramps. I doubt that alone is responsible
    for my tire edge wear.

    Around my 30,000 service I plan to replace the factory tires, so I'm eager to
    learn what folks recommend here. So far, the HydroEdge seems like the most
    consistently recommended choice, but with wide variance in opinion.

    /Gordon
     
  17. ghostofjk

    ghostofjk New Member

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    <div class='quotetop'>QUOTE(fastlane @ May 11 2006, 02:16 PM) [snapback]253718[/snapback]</div>
    You WHAT?

    If you averaged, say, 51 MPH on your 40-min. drive (2/3 of an hr.), you went 34 mi.; and if you averaged, say, 50 MPG at that speed, you used about .67 gal.

    Did you fill up at the beginning of the 40-min. drive, then fill up again? If so, are you sure the gas tank was full to the same extent both times?

    I doubt anyone can measure gas consumption this precisely using so little gas.
     
  18. fastlane

    fastlane New Member

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    <div class='quotetop'>QUOTE(ghostofjk @ May 11 2006, 08:08 PM) [snapback]253830[/snapback]</div>
    With all due respect... C"MON DUDE!!! what are you thinknig? Of course I didn't measure the fuel efficiency at the pump for the love of 'a pete! Maybe you have noticed the huge protruding screen in the center of your dashboard? There are several buttons on the sides of this screen and one of those buttons will bring you to an interface that displays fuel efficiency and battery charging & capacity.

    Before you all start clamoring to explain how inaccurate the computer mpg rating is, blah blah blah... let me say that its accuracy is not that relevant in this case. I think it is safe to say that the ratio of it's accuracy is within a reasonable margin of error. I know the car and the way it behaves under various circumstances and when computer is telling me I am averaging about 35.5 mpg during a sustained bit of travel that would normally yield a computer rating of 43-45mpg, i think it is safe to say that i have experienced a "significant drop in fuel efficiency." I am sure a more concise series of experiments could narrow the mileage hit down to a few thousanths of a milliliter, but i really DON'T CARE!!! It is pretty clear to me that there was a large drop. PERIOD.

    During that initial drive I did a series of driving maneuvers and practiced various driving intensities / styles and everything I did yielded VERY noticable drops in fuel efficiency compared to the old tires - according to the computer.

    Watching the fuel guage drop faster than it ever has over the next day and a half (approximately 110 miles since yesterday) has confirmed my initial results.

    Furthermore, although i didn't mention this before, I also noticed that my battery would discharge very quickly after short stints of more "spirited" driving. And frequently, even in moderate freeway traffic, the battery meter on the computer screen would display only 4 or less bars as charged. Normally, i see all but the top 1 or 2 are green and ready.

    Needless to say, and as much as I hate to part with these tires because of the feel and the improved handling, i will be. So what do i go to instead?

    Still looking for info on a great riding tire that won't kill the mileage. Is there anything elso out there besides the comfortreads or the hydroedge? Don't the hydroedge cost a fortune and still give you a fairly significant hit on fuel eff? I am also concerned the comfortreads will handle poorly, but i suppose taping broken pieces of wood to the rims would be an improvement over the Integritys.
    Thoughts? (Not critiques please)
     
  19. NuShrike

    NuShrike Active Member

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  20. talonts

    talonts VFAQman

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    <div class='quotetop'>QUOTE(fastlane @ May 12 2006, 03:02 AM) [snapback]253990[/snapback]</div>
    Yes, the HydroEdge are "expensive" - compared to other tires in this size. I got mine for $496 OTD with Road Hazard Warr, etc, from Sam's Club (no $50 rebate there, unfortunately, not like last year). There are obviously much cheaper 185/65-15s out there. But you want better handling, so forget those cheap tires.

    As for the mpg hit, there isn't one. I tracked mpg when installing them on my 04, and yes, there was a 1-2mpg hit for the first 1K miles or so during breakin. Since then, zero hit (over 10K miles on them so far). When I installed them on my 06 I didn't notice any hit, but I've only had them on for about 500 miles so far.

    If you can ignore the price, the HydroEdges are hard to beat. Especially if you ever have to drive in any appreciable rain (with a 6 mo hurricane season here, I do, so that was of great importance to me).