Best Tire/Wheel Combo Science experiment

Discussion in 'Gen 2 Prius Accessories & Modifications' started by Escalade_on_22s, Apr 12, 2006.

  1. Escalade_on_22s

    Escalade_on_22s New Member

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    I've owned my Prius just over one year... 35000 miles later I've come to a few conclusions: The stock tire/wheel combo is ALMOST as good as it can be for mileage. The stock tire is very light (17 lbs), but performs like a nightmare, almost dangerous. The stock wheel (14.4 lbs) is also very light, but somewhat unsightly. For 20000 miles with stock trim my overall gas mileage was 47.3 MPG.

    At 20,000 miles I "upgraded" to the Scion TC wheel/tire, which resulted in 1.5 seconds MORE time to get to sixty, and an average of 42.2 MPG over the last 15000 miles. That's a degradation of about 11% in fuel economy, and completely lethargic performance. The car was stabler, but it's not overall worth it IMO. The Scion wheel weighs over 20 lbs, and the Bridgestone Potenza 92 weighs a staggering 23 lbs! That's a 43 lb wheel/tire combo (what most trucks have), and nearly 35% increase in rolling resistance to acceleration! Terrible. Do not make the same mistake as I, but if you do then please by my Scion rims, I'll practically give them away.

    Today I purchased the Wedsport TC005 16x7 (12.7 lb), and the Firestone GTA-2 tire (19.6 lb) from tire-rack.com for around 1500 bucks. This is nearly identical to the stock weight, and should provide incredible grip/stability at high speed. I'll mount them this weekend and post the G-Tech results here. I expect at least stock MPG numbers, if not higher due to increased sidewall rigidity and less weight in the bead. I think the second best combo would involve the Motegi Tracklite 17x7, but the 17 inch tire is gonna start weighing you down, and it's profile is a bit too wide to help in fuel economy. Please post you feelings here if you've seen anything better.
     
  2. samoan_ridah

    samoan_ridah New Member

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    So let's talk scion tc wheel give-away... :)

    Seriously though, I'm willing to take them off your hands and from taking up valuable space in your garage.
     
  3. koa

    koa Active Member

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    I was thinking about the Scion wheels but didn't realize the weight difference. Thanks for pointing that out and please continue to post your experience and data with the new wheels.
     
  4. Escalade_on_22s

    Escalade_on_22s New Member

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    <div class='quotetop'>QUOTE(samoan_ridah @ Apr 12 2006, 02:29 PM) [snapback]238674[/snapback]</div>
    OK, well I live in Ridgecrest CA. I really can't give them away for free, but if you include shipping I'm willing to part with them for pretty cheap. They're painted black with a clear coat (and very clean with minor tread wear) so they'd probably look good on your car. Make me an offer.

    Bryan 702-860-6673
     
  5. samoan_ridah

    samoan_ridah New Member

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    Hmm, black eh? Got any pics of them on your car?
     
  6. bestword

    bestword New Member

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    I've been lurking for a coupla' months and finally decided to join so I could actually post. I've been reading this thread and the BT stiffening plate thread in particular hoping to find some clue as to a remedy to some of the straight line handling shortcomings of this car.

    Other people's observations: People have commented that if there's someone in the passenger seat the handling seems better. Interesting, could be a weight distribution from left to right or perhaps the front verses the rear, which could indicate camber has been increased from the suspension deflection overall in the front, causing a different attitude relative to the road, resulting in better lateral stability.

    Characteristics I have observed: The car seems to be the worst at following little imperfections in the road like rain grooves cut in the pavement that allow water to move aside allowing the tire to contact the road more completely.

    I noticed that the rear wheels have some naturally occuring negative camber, this doesn't seem to be present in the front wheels.

    How about adjusting the front camber somewhat toward the negative. Does anyone know of anyone who has tried this. Is the front camber even easily adjustable on this model?

    Additionally, I would love to know what the did to the camber adjustments of those 3 racing Priuses. I sure would love to drive one of those. :)
     
  7. FredWB

    FredWB New Member

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    <div class='quotetop'>QUOTE(bestword @ Apr 12 2006, 07:44 PM) [snapback]238890[/snapback]</div>
    I've never noticed it handling better with a passenger. That could be that we're less likely to admit we bought such a poor handling car, I don't know. I guess at one time I was the most vocal about the Prius handling. Not too much has changed for me except to admit that I can't change what I can't change. The roads here in San Diego are about the worst on the Prius and so my car is still all over the road. I had a camber correction made early on when I found the right was different from the right. It made no difference corrected at all. Maximum toe in on the front will help the most, about -0.2 deg (or -0.080")

    I even tried the Scion tire and wheels after numerous attempts at trying to improve things with alignments, etc. I found like others that those tires only slow you down and reduce the gas mileage. They do improve the stability somewhat but at too big a price in my opinion. Yeah the Prius just doesn't track in a straight line like even some mediocre cars I've owned and it's much worst than the best. It sort of takes the fun out of getting 50 mpg sometimes. You'll find that if you're one of those people that notice how poorly the Prius handles (some don't or actually say just the opposite if you can believe that) you probably won't be very satisfied after spending money on good tires making small incremental improvements. It's too tall, too narrow, too softly sprung, dampening isn't right, no sway control and oh yeah the electronic PS sucks. So improve on enough of those you might be happier but I'd just put some good tires on it and enjoy the good gas mileage.
     
  8. Escalade_on_22s

    Escalade_on_22s New Member

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    <div class='quotetop'>QUOTE(FredWB @ Apr 12 2006, 10:32 PM) [snapback]238926[/snapback]</div>
    I agree with all of this, but there's always a decent solution, usually it just requires a little time and money. The prius has the design to be an exceptional handling car (low CG, wide track, wheels at the corners), but to keep costs/weight down and to improve low speed ride quality Toyota opted for the cheapest suspension available. I think the stock struts/shocks/springs are crappy ill-handling junk. The first time I got my prius to 110 in a cross-wind during desert testing it looked like a Russian circus inside the cockpit. I've opted for the TRD Sportivo suspension which offers a progressive spring rate and brings the cars CG down about 20-25 mm. I'll dial in a little negative camber on the front when I get the TRD Sportivo suspension kit in, and see how that goes. I'll be happy if the thing stays in its own lane without major effort at highway speeds (70-90) in a crosswind environment. I drive a few thousand highway miles a month through Death Valley on my commute to work, so this will be a major improvement. I'll post my results once the kit is installed (7 weeks).
    Bryan
     
  9. bestword

    bestword New Member

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    <div class='quotetop'>QUOTE(FredWB @ Apr 12 2006, 08:32 PM) [snapback]238926[/snapback]</div>
    Thanks, I'm still gonna have to think about this one some more. Maybe I'll just have the dealer perform a toe-in correction toward positive. Anyway. I wanted to say, your car looks great in red with those wheels. Really good in red, i almost got the salsa red but they changed it to a more bright red in 2006.
     
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