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Freeway Straight Line Stability

Discussion in 'Gen 2 Prius Main Forum' started by FredWB, Feb 6, 2004.

  1. FredWB

    FredWB New Member

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    So after 2 trips to the Toyota Dealer and one to Van's Alignment here in San Diego the verdict is that my car is as good as it's going to get. I found that after the 1st alignment that Toyota did (it was out) it did improve a lot. I still would not call it rock solid, especially if you encounter road grooves or side winds, etc at 65+ mph. With the soft suspension, narrowish tires, narrow track, tall profile, I feel I have to pay more attention to trying to keep the car going straight. Corrections seem to cause the car to want to wiggle so I've learned to keep the corrections small.

    I've also tried differnent tire pressures and have settled on 40/38. This didn't seem to affect things much. I do know that once these tires wear out I'll probably go to something "better". Have to research that first. I had a Mazda RX-7 '93 that was the most squirrly car I ever owned. It had brand new Yokahama Tires and after alignements, balancing, etc, I finally put on Bridestones and WOW....what an amazing difference. So that might the solution here too. I drove our 2003 RSX, not a car noted for it's straight line freeway performance and it's really a lot better than my Prius. I know, it's smaller, wider tires, etc, but it's been noted in magazines tests that it's not that great. But I do feel like it (the Acura) wants to go straight at 65+ mph. My Prius, left alone, would drift right or left every time unless I correctly continually.

    Does anyone else have the same issues or is it just my car. I'm convinced the alignment is OK now so I'm not sure what to do maybe but learn to live with it. My Acura mechanic drove it a little and he even said it felt very "twitchy" to him, so it's not my imagination. There's just nothing I can really do I guess (except maybe check tire balance next). My wife would never feel confident enough to drive it though. Hmmmmm, maybe that's a good thing huh.
     
  2. efusco

    efusco Moderator Emeritus
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    I agree, I wouldn't go so far as to call it squirrely, but it does have some sensitivity. On the hwy tonight I was thinking about that. I think the option of 16" wheels might help somewhat--those who do a lot of hwy driving and don't mind the mild hit on MPG could get the bigger wheels. You DO have that option, btw, they'll fit.
    --evan
     
  3. mikepaul

    mikepaul Senior Member

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    I haven't tried it in a couple of weeks, but when I did, I couldn't point the car straight ahead and have it go that way for more than a second or two at 70MPH.

    It didn't always pull either left or right. It wandered on an equal-opportunity basis...
     
  4. FredWB

    FredWB New Member

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    Yes I did have some pulling. More like drifting left according to the tech before he aligned things. Now it's about equal. While I would not say it's squirrely on asphalt. It is on some of the more heavily grooved cement roads here. The they've tried to add more lanes so the deeper grooves that used to be between the lanes now is usually right under one of you tires! Sometimes those are hard to avoid. And I usually stick to 65 mph but today I pushed it up to 75 once and it was worst. It really reminded me of the RX-7. That car was scary when you found yourself on a grooved freeway between to large trucks doing 80! But a tire change was like night and day and that may help here also.

    Just a different tread pattern, one that doesn't have the groove in the center, but rather two smaller grooves and an extra block of tread right in the center (narrow in width), like the Bridgestone Protenza RE 950, seems to help a lot. I think I can put up with it for now until more owners replace tires and see what's working better. Even something the next size up in width but the same size and circumference might help. But it might also hurt mileage too. I've heard that next year the tire manuf. have to label the tire's rolling resistance so I might even be able to not loose too much with the right tire.
     
  5. Jerry P

    Jerry P Member

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    I noticed that the steering has a lighter feel than my Echo did -it ran dead-straight, even at 85 mph. It took a bit of getting used to, but I blamed it on the new snow tires I put on 2 days after I got my Prius. It got better after a couple weeks and I guess I'm used to it now. Brigestone has a replacement tire out for the RE950 that is supposed to be the best ever. They brought it out at the Chicago auto show, I think. I might consider them, along with some VERY light weight wheels in the spring and just keep the snows mounted on the stock wheels. Lower unsprung weight should improve the already nice ride.
     
  6. artie

    artie Member

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    hi
    i too am in san diego fred, and tho i only have 300 miles (and therefore too new to judge) i've been very pleased by the cars straight line ability on the slab. yes, it does seem very sensitive to my touch, just like my '90 Miata that i had for 10 years. for the last 3 years i've been driving a lincoln and so now i need to re-develop the sensitive non-intrusive touch i once had. but if i keep my hands off the wheel, so to speak, the car tracks incredibly well and straight.
     
  7. Jonathan

    Jonathan New Member

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    I am still battling with the squirly (my term) steering. I had my 04 re-aligned at Toyota and still feels the same. I want to try changing tire pressures, front vs back, to see if that helps.
     
  8. overcooled

    overcooled New Member

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    We could have gotten our 2004 Prius on Friday evening, but we decided to allow the dealer have it over the weekend. That may have been a good choice or it may have nothing to do with the allignment.

    My motorhead friend drove the Prius on a flat portion of a local divided highway. It is two lanes in each direction and surrounded by farm land where we were.

    He floored it several times until it got past 60 mph. He let go of the wheel while cruising at 60. It would pull to the right. He stopped the car and squinted. He tried the same thing straddling the two lanes and the car stayed in a perfect straight line. Then, at 60 mph with no hands on the steering wheel, he hit the breakes very hard, but not hard enough for the ABS to engage. Again the car stayed straight.

    He was very impressed.
     
  9. FredWB

    FredWB New Member

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    I sure wish I could say the same about mine. It does not pull when braking, just has this little twitch. You can sort of feel the back end wiggle like you're towing something only it's the Prius. I suppose I could go back to the dealer and try again but at this point I've spent about a day and half sitting and waiting around for it. And I just don't want to hear that familiar "It's normal" from them.
     
  10. Tom

    Tom New Member

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    We drove about 45 miles today on the freeway in slushy snow. The handling was good except for the sensitivity in the steering. There were high winds on the way there. On the 45 miles back home, the snow had melted but the winds were still gusting.

    Isn't the steering by wire between the steering wheel and the steering rack mechanism?

    Although there is spring back to the steering wheel when turned, at the center there is little sensitivity or "feel" in the steering wheel. I found myself reacting to the visual movement of the car and trying to correct that rather than feeling a heavier push coming through the steering wheel with a new wind gust and naturally reacting to that by a sensitive correction. Any thoughts?
     
  11. plusaf

    plusaf plusaf

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    ok, this is just theory, but if the car drives straight when straddling the centerline of a two-lane but goes to the right when you're in the middle of your lane, it might be that the road is crowned. years ago, front suspensions were set up to actually pull a bit left to balance this out, but as more and more roads and superhighways became "flat", i think this has died out a bit and cars are set up to track straight on flat roads.

    my 2 cents...
    :)
     
  12. RobertO

    RobertO New Member

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    I have to say that, as one of your more obsessive-compulsive, picky guys, I really can't fault the 04 Prius' steering so far (5,500 miles).

    A few months ago the only thing I changed relating to wheels was to lose the useless trim rings, install metal stem caps and raise PSI to 42 front and 40 rear. That's it.

    I've only forced the VSC to come on twice, that while climbing up a mountain east of Seattle on a poorly-maintained and designed, reverse-camber asphalt road. (OK - so I was lost and trying to make up time ...)

    I dove it into a particularly manky V-turn (lay the "V" on it's side - you'll get it) and a sensed a trifling hesitation, felt NO tire slippage and glimpsed the VSC snapping on twice in 3 seconds. Haven't seen the VSC come on since.

    This included driving in snow, ice and slush earlier this year, by the way.

    Like many lighter cars, my Prius will try to track or climb wear valleys in freeway pavement, but not to excess.

    Even my brute (weight-wise) of a '91 300E would do that, time to time.

    I don't really want to defend Toyota Motor Sales of North America Company, Inc., as I DO have other issues (believe me, they know), but on the matter of steering and handling, this car has become a very pleasant surprise.

    Toyota made some compromises in delivering this 2nd genration hybrid. Every manufacturer ends up having to do this. You have to freeze the product at some point and ship or it will never get to the customer base.

    Some announced features did not make it into production. Some features are not available in the U.S.

    For this car, above average handling was included. I'm happy with the way my '04 Prius handles.

    If I want more I'll do some sort of "priuschat.com concensus handling tweak" (that probably becomes popular in a year or two) to the rims, tires, springs, etc, or buy a damned sports car!


    Bob
     
  13. Stilview

    Stilview New Member

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    3500+ miles so far, and I must say that the car is not stable in high winds. A Jeep Cherokee needing new tires is more stable in head or cross wind conditions.

    Despite that, I wouldn't trade it for any other commuter.
     
  14. Ray Moore

    Ray Moore Active Member

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    I don't understand what ya'll are talking about. On Friday, I drove my new car with the cruise set at 72 in strong cross and head winds across north and west Texas. I drove 900 miles around and sometimes through strong thunderstorms. I only had to slow down twice due to poor visibility. I was impressed by it's ability to handle gusty winds at high speed. I never felt any bad manners and haven't experienced any pulling or fading. I'm impressed with this car. Just enough performance in all regards. In my opinion, this car should be the absolute minimum vehicle that we should expect from manufacturers. That we had to wait so many years for this to hit the market is shameful. My next car will get 80 mpg. I sure hope I don't have to wait 20 or 30 years for the auto makers to provide it because I really don't want to drive this car that long.
    Ray
     
  15. priuspilot

    priuspilot New Member

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    I am very happy with our Prius handling. Have driven in the winter to NH from OH in blizzard and gusty wind conditions and all over OH area and find the car to be very stable - tracks true. I am picky about this stuff as a pilot and a car buff. I find the steering to be light at all speeds, which I think is a result of the "electric" power steering. This is different than most cars in that they tend to increase the resistance as the car gets faster. It took no time to get used to. The only criticism I have about the car’s handling is a little too much body roll in hard cornering.
     
  16. efusco

    efusco Moderator Emeritus
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    Yea, I'm jumping on the "handles well" bandwagon. I'd say it's slightly more 'twitchy', but if it was a sports car they'd call the handling "tight and responsive" and add a few thousand dollars to the price for it.

    When the wind gusts, it rockes, just like every other car it's size. But to call it "unstable" is not reality, it's quite stable. "Unstable" suggests a reduced ability to maintain directional control and I've not experienced that at all, at least not any more than every other car on the road was experiencing at the same time.

    BTW, I'm gonna start a thread to find out just how many pilots we've got on this board.
     
  17. Tom

    Tom New Member

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    the last three posts are what I needed to hear. The car we have exhibits this particular "steering problem" (for lack of a better definition).

    When we were deciding to order the Prius we rented a Prius TRAC car for two days, drove it freeway and country roads, and never noticed any handling twitchy-ness. The rental drove perfectly. Except for this problem, the handling is excellent.

    I called the Service Mgr. at the dealership today and he noted my concern. We agreed that I will ensure that the tire pressures are correct and drive it for the rest of the week to see if it continues to exhibit the problem. Then, if it still wanders, I will take it in. I was hoping that I would get responses from technically astute drivers and I thank you for replying.
     
  18. Eug

    Eug Swollen Member

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    I think it wanders slightly at high speed (>100 kph). It was slightly worse when I first got the car. Now after a few thousand km it's better (tire break-in?) but it's still there, esp. in high wind.

    I did not notice this issue with my 2001 Prius. I will definitely mention this to my mechanic when I take it in for my oil change.

    I'm hoping it's just a tire issue, and not a steering issue.

    On the bright side, the handling of the 2004 is WAY better than than the 2001 in the snow, and I attribute a lot of that directly to the low rolling resistance tires of the 2001.
     
  19. sparkymarvin

    sparkymarvin Member

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    Just to throw in my two cents,

    In past threads on PriusChat people have mentioned this stability problem. Some think (and I mainly agree) that during shipping the meathods for securing the car can misalign the steering. Perhaps this occurs more with the Prius because it has to make a trip overseas.

    I had trouble with my car on the highway. I determined that the right front wheel had a toe-out problem, brought it to the dealer, and they aligned it under warranty.

    The car drives beautifully now.

    ~Andrew
     
  20. FredWB

    FredWB New Member

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    I finally took mine back for the 2 try at the alignment. To get their attention I told them that my wife was getting vertigo and would not drive in the car! They "tweaked" the toe in one more time and it really made a big difference this time. Before it was .01 left and .20 right for the frt toe....now it's .08 and .06 respectively.

    I think you guys that say the car is perfect just were more lucky while others were not so lucky with this. We have lots of freeways here where they've tried to add another lane by making all of them smaller slightly. So you end up with these deep wide grooves that used to separate the cement lanes (expansion joints). These now end up directly under a tire. And no matter what you get pitched side to side. And all the cement freeways have very deep rain grooves, some worse than others. If you drive on asphalt freeways or freeways without grooves I don't think you'd notice any handling problems.

    I still think the car is somewhat tall, soft suspension, long wheelbase, and somewhat narrow track and tires. That along with the power steering assist gives the car a quick light feel and also a sort of dead zone when going straight. To me this is just the characteristic of the car and if the alignment is right the quickness can actually be nice and the urge to wander not too bad. No I don't think it "tracks" in a straight line like my wife's 2003 RSX, but it's now not all that bad. Maybe someday a tire change will improve it more too.

    The bad news is that I noticed today that somehow someone at the dealer damaged the edge of the driver door. The paint is all chipped off along the edge for about a half inch! It's like it was opened into a cememt wall by accident! I'm just a little bit sick and have to go back tomorrow very early. Maybe it was that veritgo little white lie I told????