Poor steering and handling on the highway.

I confess I'm the San Diego owner that's tried nearly everything under the sun to fix my wandering Prius. There's also another member of our group that told me he has the dealer commited to putting in an new PS assy. Expensive if it's the problem at about $5K if you had to buy it. My current dealer says the PS is not adjustable BTW.

I'm to see yet another Toyota factory rep this wednesday. I'm prepared for him to tell me it's normal and just finally give up on this ever being any better. For all I know at this point it is close to normal and it's just our very worn and over-groooved freeways on 15. At times it feels so close to normal and then it will hit a section of road or "something happens" (wind or rough road???) to suddenly cause the car to feel like it's got a hinge in the middle. At this point I think if I lived where the all the freeways were smooth I could almost put up with the occasional sway and side movement from wind and passing trucks. But on wavy grooves I too feel that others might think I'm drunk at times. Maybe I should be and I would not be so concerned about this.

My camber was out, meaning the right side was a lot different from the left. I had that fixed with no improvement and it really should not have caused the car to wander. I think the front is now about -0.5 deg on both sides. The last time to the dealer I paid for an alignment prior to Toyota visiting and found the last shop had it at 0.0 left toe-in and 0.08" right. The dealer set it to .03" and .04" respectively now. Tire and tire pressure don't seem to have any kind of measureable effect except that the Michelin Hydrodege tires do seem better. I guess my car is now as good as it's ever been but not as good as any other car I've owned.

I don't think we need to give Toyota names of people that think that their car is perfect because after all..."they've never heard this complaint before", right? So they must think that there's only one of us at any one time.

 

Oh almost forgot about this article I just found. The author crossed Australia with the 2004 Prius. I notice that they said their car had 195H65X15 tires too. Oh and the comment below is just one of many I've found from testers that commented about the less than stellar highway steering with the Prius. Or maybe they got a bad one like me too. But constant correction and tiring and tedious driving seems to be common theme for those of us with this problem.

http://www.autospeed.com.au/cms/A_2036/article.html

Here's a quote from the article above:

Mother nature also blew in gusty crosswinds - and the Prius hated it. So did her driver. As is the case with many very low drag cars, the Prius (cd = 0.26) is susceptible to crosswinds. Constant corrections are needed to keep the car on the straight and narrow, and with an unfortunate (electric assisted) steering system that lacks feedback and has a slow ratio around centre, the outcome is tiring and tedious.

 

I drove about 60 miles today at highway speeds to see if the handling is any better after the slight camber adjustment. No joy, it's still the same. This is with Goodyear TriplTreds on the car, and at this point the only other thing I can think of is to try a different set of tires and see what happens.

I'm headed out of town next week going to an area where Enterprise has some Priuses. I think I'm going to try to rent one (again) and see if it feels any different from my car. I just can't figure out if this is the nature of the vehicle, or if it's something with my particular car. I would swear the rental I had for a day before I bought my car didn't have this problem, but maybe I just wasn't paying attention, or it was a perfectly calm day.

Very frustrating situation.

Geoff

 

When you drive the rental, try to pay attention to if you feel relaxed rather than tense after driving it in traffic. My experience so far is that the differences between a good and bad car are more subtle than I first thought. My car tires me out where the other Prius I drove, 3 now, did not. My perception is that they handled on grooved roads like my car did on smooth roads. There is some subtle difference in how the cars track compared to one another. It's really difficult to put your finger on it though. My car can be pushed left or right much easier it seems. A passing van or truck, a side wind, or wavy grooves in the road all seem to have a larger effect on my car than the other Prius I've driven.

When I compare my Prius to something like my wife's RSX, while not really fair, the differences are much more pronounced. One steers lightly and has very little center tracking while the other tracks much, much better. I think that's why it so hard to convince Toyota or the mechanics that there's any difference in our cars. When I just let my car go on a straight section of road, sometimes it will go straight, sometimes it will immediately drift left or right. It's this movement to the left or right that results in the corrections we have to make almost constantly at times that is so tiring. The car tends to sway a lot while correcting too which only makes it worse. Add to that some narrow lanes, concrete barrier right to your right (no room to drift there), passing truck to your left and maybe an expansion joint right under your left tire with a heavy wavy grooved surface and you can have a very scary, dangerous experience. These are the typical freeways I drive on around here in SoCal.

 

When I had the TSB done recently I had a 2005 Corolla loaner. I felt it handled as bad if not worse than my Prius. Guess what? I think it has a new electronic power steering too according to an article I just read about it:


Quote from the 2005 Corolla article:

"New electric-power steering is too light and lack of feel, especially at high speed".

Can anyone confirm this? Thanks

 

its too bad that a number of Prius owners have handling issues and there seems to be no real consensus on the cause.

unfortunately, the number of people with the issue is small enough that Toyota doesnt seem to be seriously addressing the issues.

i do feel some handling issues at times in my Prius, but i feel that the conditions are fully to blame and not the car.

i frequently travel over several bridges that have severe shear winds all the time.

remember Galloping Gertie?? well that bridge was basically blown off its foundations because it didnt allow the wind to travel through the bridge.

well the replacement (tacoma narrows bridge) does allow the wind to pass through it resulting in a harrowing drive at times.

every year, a camper pickup or some high centered vehicle blows over or causes a wreck.

i still say my Prius is a dream to drive compared to my ford pickup.

 

I'm getting ready to see the Toyota rep on Wednesday. I'm not sure how I'm going to approach this because it's supposed to rain here and that means no real chance to get up to speed on the bumper to bumper freeways. I think I'm just going to talk with him about the problem. My car is about as good as it's going to get without some PS calibration, radical change in suspension component, or some undiscovered tolerance issue somewhere.

I've put together about 8 comments from various sources that commented on the less than ideal steering. They can't all be wrong. But keep in mind that this is from road testers that have a chance to drive all sorts of vehicles from the very best to the very worse. Almost all of them had some negative comments about the freeway steering. They ranged from "less than communicative" to "numb and detached from road feel" to "a steering system that lacks feedback and has a slow ratio around centre, the outcome is tiring and tedious".

I've read that the European Prius suspension is much tigher with extra rebound springs so I'm hoping that someday something like that will be available to the US. TRD has nothing available yet. Maybe a kit with components from the GT Prius they built would be nice. I guess I'm just very hopeful the someday I'll be able to improve this somewhat. One of these days I'm going to get my fellow engineer and Prius owner Henry Eisenson to drive my car again. He noticed a difference long ago and maybe now our cars are more alike than I think since my several alignments and Michelin Hydroedge tires.

 

It sounds like the last one most closely matches your problem, as you have modified the car (tires, etc). Although I think much earlier on you said the car dashed off to one side almost on its own. That is a description of a much more severe problem.

Since most of us, and you in other Prii, wouldn't use either of those descriptions even with OEM tires, it really does seem that your car, and a few others, have some almost unique problem. I hope the Toyota rep can figure it out.

 

definitely get the car checked out. i know a guy who goes to my gym who has had similiar problems.

he is seriously thinking about going to an independent mechanic to have the car completely gone over.

i have suggested driving his car to see if i felt the same way about his handling problems but he nixed the idea. (i dont really know him. we happened to pull in at the same time one day and i asked him if he had heard of Priuschat)

 

My friend owns an independent Honda shop and he's really pretty sharp. The very first time he drove it only on the street he comments on it swaying so much and that it didn't seem to want to track. He wanted me to put on 17" wheels with 215 tires right away, not appeciating what the car was all about. We both put it on the lift and checked every single suspension attachment. It was obvious the dealer had already been there by the wrench marks. He comments on the very wimply anti-sway bars and soft suspension. The rear torsion bar look identical to the Corolla for the most part.

But there's really nothing to tweat once you've done the alignment. We were going to try disconnecting the PS but since he didn't understand it all that well thought better of that idea. One other SD owner with this problem swears that 2 10 lbs weights up in the nose of the car made a dramatic difference. He's the one getting the dealer to change out the PS unit. After driving the 2005 Corolla with it's electronic PS, I'd say that they both feel kind of squirrly.

Mine is much better than when I started but still is a very tiring car to drive when side loads push the car around. I just don't hold out much hope unless some tuner makes stiffer shocks and springs available. I have looked. While not the source of the problem necessarily, my feeling is that the rolly-polly nature of the Prius makes the problem worse. I never did like how Caddilacs used to wallow down the road and sway on corners. To me it's more like the Caddy than the RSX or even my old 1990 CRX-SI. It is more comfortable on rough roads than those two cars mentioned and I guess that's what most Americans are used to and prefer in their cars.

 

I earlier mentioned that I had wandering problems as well. I decided to test the tire pressure to see if it would change things, and it did. All my tires were right around 35 psi and when I increased the front to 42 psi and the rear to 40 psi, the problem seems to have disappeared.

I think that the car is probably still very sensitive at higher speeds but the increased air pressure combined with my having gotten accustomed to it for about 8 weeks now seems to have solved the problem.

 

really?? well congrats on the fix!!

do you think it was the higher pressure or the 2 lb diff from front to rear that did it??

 

<div class='quotetop'>QUOTE(DaveinOlyWA\";p=\"47491)</div>

Dave and all, the owners manual says to put 2# more in front than in back... I run 44# and 42# and I swear my car runs straight on any road at any speed.. when I got the car, the presures were anywhere from 34#-38# no two tires were the same... I have tried 38#-44# in the front and up to the 44# the front end felt heavy or mushy... I guess I do get a little rougher ride with the extra air...

Bob Andersen

 

welll i have always had my air pressure at 38.5/36 but the 2 lb air difference was always there. i think it all depends on how conscientious your local toyoda maintainence guy was when he did your pre delivery checklist.

from what ive read, some are not that detail oriented.

 

A few Priuschat members have gone to different wheel/tire combinations eg. 195/60/16 for a different look (see Album section of Priuschat). I'm curious as to the effects on handling and crosswind sensitivity that different wheel/tire packages have produced. I owned a VW Westphalia van in the (distant) past and it was real twitchy at highway speeds. I installed KYB gas shocks and a light truck tire (for stiffer sidewalls) and it made a huge difference.

 

changing tires will affect handling and mileage but i think i read somewhere that the major cause of wind shear problems stem from the low Cd of the car.

in normal circumstances, a higher Cd is caused from multiple points of resistance to air flow around the car. this causes downward force onto the vehicle making it contact the road better and making it less vunerable to side forces like wind.

the Prius is unique in that it has a very low Cd but is not slung low like sports cars that share the low Cd characteristic. in fact, to create more passenger space, many of my friends have commented that the car appears to be "tall and thin" from a distance.

add to that the low rolling resistance tires that come standard on the Prius and that has apparently left some vehicles prone to handling problems.

as far as lower pressure possibly being a partial cause of the handling issues, i dont know. my car has never had the standard air pressure ratings as that was the first thing i did when i picked up my car was to adjust the air pressure higher and uniform. i have never had a handling issue except for one instance going over the 520 floating bridge in seattle and i can say that handling issues on that bridge is never the fault of the car. side shear is a daily issue and a critical one frequently in the winter where bad weather tends to cause accidents on that bridge weekly. even lowering the speed limit doesnt help. (i've seen plenty of times where the speed limit was reduced to 35 mph from 60 just for safety reasons)

but i think that all the factors above maybe contributing to a design that is very sensitive and the smallest out of spec measurement maybe the cause of everything. i wish this was resolved because i would like to know what it is i should be monitoring closely. although my car is fine, i feel that im probably teetering on the border of handling issues too.

 

Fred, any news about your meeting with the Toyota rep?

 

I'd like to offer an explanation on this steering "problem" that I have not seen suggested: the electrically assisted steering is set up to be very tight, that is with very little looseness or steering wheel play. The result of this is the average driver's need to needlessly correct the car's direction of travel which results in what is being called "wandering". Just after we got the car, I had a friend drive the car who drives a 38 foot motor home and the steering problem was most evident. He was correcting the wheel constantly and the ride was nearly sickening.

I have found that the car will respond quickly to very small steering inputs and I have to to try very hard not to be correcting all of the time. If I hold the wheel at the 6 O'Clock position, on the very bottom, I can add just the right amount of input with out wandering all over the road. Turn the top of the wheel just a quarter of an inch and the car will move in that direction.

With other cars, our twelve year old Passat for example, there is a lot of play in the wheel and I do have to correct it all of the time. If I drive the Prius the same way it "wanders", only, of course, because that's what I'm causing it to do.

 

Only strong crosswinds are able to bother me while driving the Prius. We had some storms (well, not really, just strong winds ) over here and on the highway I was forced to slow down from the 120 km/h speed limit to 110 km/h or so. And even then the car sometimes moved 20 to 30 cms to the side.
But other than that, I've had no handling problems on the high way (or any other road). The car drives like a dream.
Perhaps the European suspension and tyres help improve the handling somewhat.

 

I'm wondering if the drive-by-wire nature of the car makes driver input too sensitive? I recently watched a documentary on Wings about the fly-by-wire Airbus passenger jets. In the simulator, a test pilot was showing what the aircraft was capable of, but he added what I thought was an odd comment: "Generally, in this sort of aircraft, the less you do the better." He was referring to PIO (Pilot Induced Oscillation). I have noticed on my 2004 Prius that fingertip pressure on the steering wheel works best, and it tracks very straight if I leave it alone. If you try to manhandle the car, it's all over the place. I fear you could easily get into trouble with this car, especially in winter, if you were too aggressive with the steering.