Poor steering and handling on the highway.

<div class='quotetop'>QUOTE(seeh2o\";p=\"58431)</div>

I've driven two others and one of the owners, another engineer, has driven mine. We're in agreement that "something" is differnent in mine that makes it tiring when the car is subjected to side loads (wavy grooves, wind, passing trucks). But Toyota will not help further, period. There one 5 min test drive was enough for them. They told me my only option is arbitration. Both other cars were different in that the drive (40 min.) left me relax and confiident about what their cars were going to do next and when. Since I've paid for alignments, tires, etc. I'm going to pay the dealer to calibrate the steering torque sensor (zero setting). At this point I've got nothing to loose.

 

We just got back from a 2,800 mile road trip in our new 2004...roads ranged from I-40 to Mexican highways, with and without wind, and we had no problem whatsoever. Speeds ranged up to a bit north of 85, and it felt super stable.

 

If I only drove on smooth asphault, or even rough asphault, I would probably say that my car handled OK. Based on my experience with cars that really track well, ie sports cars, etc. I would never be able to say the Prius was super in any handling regard. That's reserved for cars that literally inspire confidence and as much as I respect and am amazed by Prius technology, it's just not in a class with other cars that handle. Even my wife's lowly Acura RSX inspires so much more confidence on the freeway. It tracks straight and true even on the deepest grooved freeways here. And I'm not talking about cornering ability, just straight line predictablilty. You can confidentally take your eyes off the road briefly to change the radio station and not scare the guy in the car next to you!! And the RSX is far from the best I've owned, just very good.

What I think happens to my car is that as it begins to drift one way I begin to apply the slightest correction. I do this ever so slightly because I know that it can suddenly be too much and the car suddenly drifts the other way. But if it's not enough, as is often the case, I have to apply more until I've come dangerously close to the lane markers. Then the car never seems to come back gradually. It's always suddenly, with the resulting weight transfer and sway of the vehicle in the opposite direction of the correction. And so this cycle of over or under correction begins again. If I hit very smooth road, it's hardly noticeable and easy to control. Much more predictable on smooth asphault. There just doesn't seem to be enough of a tendancy to track or want to go straight when outside forces intervene with my Prius.

Can you see that this can be subtle and that a tester needs to drive it on a variety of roads to really experience the difference. The Toyota rep just took it for a quick 5-10 min drive and pronounced it "normal for a Prius".

 

Absolutely. I've been on trips where the handling was fine for a hundred miles or more, and other times where I felt the wandering 30 seconds after I hit the highway. I think that's what makes this so hard to confirm, at least as far as Toyota is concerned.

For those of us with the problem there's no doubt it's real, and at some point I fully expect Toyota to fess up. Wait until there are two or three hundred thousand US Priuses on the road. If even a tiny percentage exhibit the problem it's going to become much harder to ignore.

Geoff

 

Here's something I read in the long term Prius test from Road & Track Magazine. So why is it that they see this, like I do, and yet others swear that everything is OK with the Prius? I have about 8 other reports like this from other magazines since the Prius came out. The head of the Orange County Prius Group insists that it's a basic designed in "feature" of the car. Well he said flaw but I'm being kind. Note the last comment about the constant steering corrections.

Taken from Road & Track 2005, Jan. Comments from their copy editor after being given the car to drive on his commute to work:

My first impression is that the Prius feels heavy and undertired. The car lacks some stability on the freeway, especially when mixing with big trucks, and any change in crosswind seems to affect its stability, causing me to have to make constant minor steering corrections..

 

Fred:

Although tires may make some difference, I doubt that alone will "cure" the problem.

Consider the car my folks own: a 2003 Buick LeSabre Celebration Edition. The stock tires on that beast are P225 60 R 16, and the old man had Michelin Harmony tires slapped on when he took delivery. I like those tires, that's why I had them put on my Prius too.

In winter, he runs studded snow tires in P215 70R 15, which is much narrower but the same OD. You don't want a wide tire in winter, especially in deep snow. The winter tires are studded Cooper WeatherMaster ST-2, running 35 psi all around.

Over the holidays I took the folks on a road trip to Regina, Saskatchewan, to visit some relatives. Even at 120 km/h on the Trans Canada, that land barge tracked like it was on rails. Even in strong crosswinds. One or two fingers on the wheel.

If a big, heavy LeSabre isn't "under-tired" with that narrow tire, I don't see how a much lighter Prius is under tired running P185 65 15.

Despite the much lower fuel economy, I much prefer the big Buick for highway driving. I sure wish my Prius handled the highway as well.

I hadn't realized just how *relaxing* a car could be on the highway if you don't have to second-guess it. I just got back from the hobby farm and realize that my arms and neck are all tense.

 

We just acquired our 05 Prius (build date 11/04) a week before Christmas. We drove it locally to break it in properly. I noticed that it is not as sure footed as my 01 NSX. However, I did not expect it to be. Once we had about 500 miles on the car I felt confident in driving it out to Phoenix, AZ to visit my Wife's Sister. We drove roughly about 800 miles in that trip. I got the car up to about 105 mph on the road past Blythe, CA. It felt pretty good. I passed a lot of trucks and did not feel that the car was too squirrely. The car did feel a bit harsh, trasferring road bumps etcetera. Upon checking I found that the tires were at 40 psi cold front and rear. I set them to 36 front and 34 rear. This is still somewhat higher than the sticker on the door recommends. That seemed to soften the ride somewhat. It is not a race car for sure, but I did feel confident driving it fairly agressively. My NSX is supercharged with headers and exhaust, but otherwise stock as far as suspension. I did add track sway bars to improve the cornering. I find the Prius is just different and interesting to drive. I find that I tend to be more relaxed as I drive it. I realize it is not a fast car and was not designed to behave like one. So typically around town I just drive it and relax. I think my wife likes that aspect of it. I am sorry to hear of so many experiencing driveability problems. I know that camber, toe, and tire inflation can have a major impact on how a car feels. In driving AutoX I take my NSX in and have the camber adjusted (more negative) to increase its bite (Tires wear quickly). If I have them adjust the alignment to save my tires I tend to lose on center feel and the car can tend to wander a bit and not track as well. Some of the guys who track their cars experiment with alignment. They will set up the car for a specific track then drive it, then come back in and fine tune it to maximize their lap times.

Perhaps it would be of value to find an alignment shop that does track cars and has the expertise to tune the car such that wandering is less of an issue and tire wear is not compromised too much.

It might be worth an experiement to get several Prius owners together and select an area to drive where the driveability issue can be demonstrated and see if all the cars behave the same or is it in the hands of the beholder.

Anyway good luck to all of you having the issue

 

<div class='quotetop'>QUOTE(drmanny3\";p=\"62574)</div>

Been there, done that. I've had the car fully aligned and tweaked at least 6 times. It's as perfect as you can get it right now and I would NEVER call it relaxing. It has about .03-.04" toe-in right now and the camber was adjusted on the front to make them both -0.5 deg. None of the highly recommended shops could improve on this. Have driven two others, my only observation is that driving them is much more relaxing than my car. Something is differnent about mine and others here I think.

I need to pay 100% attention to the road 100% of the time. A typical situation is coming home in the rain having to merge from a lane on the right that is ending while in a gradual sweeping right hand turn. The car will typically go too far to the left of the new lane most of the time and then I'll have to make an abrupt correction. Then the small corrections seem to have to made constantly to keep the car in the lane. And I only do 65 mph. God help me if I tried 105 mph like you did!!

If the Prius is so darn good, then why did Road & Track say EXACTLY the same thing about the steering in there long term test in the most recent issue? And there have been many other comments just like this in the press as well. Like the Buick metioned in another letter, my wife's RSX is such as easy car to drive on the freeway compared to this. That RSX really really TRACKS. No surprises...it just feels predictable and stable unlike my Prius, which goes wherever it's pushed by outside forces...wind, grooves, passsing trucks.

 

Sounds like you have done about everything one can do. How about asking one of the other Prius drivers (an owner with a car that drives the way you feel it should) ask that person to drive your car and see if they can feel the difference. This would certainly validate your understanding. The only other thing I can think of is to have the car checked on a frame device used to repair cars after an accident. There are ones out there that can measure millimeter differences. Also when the guys take their cars to the track they sometimes balance the car by weighing each wheel and adjusting the balance of the car. If you can get a car that drives properly you can then compare the two to see if you can identify any differences. I am in Orange County and would be willing to help if I can.

 

<div class='quotetop'>QUOTE(drmanny3\";p=\"62873)</div>

I had another fellow engineer drive mine before I drove his. At first he thought it felt OK and then he picked up on the difference. His comment was that it would be very tiring on a long trip. He's a very careful observer and picked up on the problem after a couple of freeway miles. If you don't own the car and drive it all the time it might just feel like a light and extremely responsive steering vehicle. But on some poor sections of road, if you're not paying attention, you're into the next lane suddenly and without much warning. It's almost like it first on the two left tires, then the right ones, then the left. Lets you know what a bobble head feels like sometimes.

I know this last statement is going to upset some people, but at this point I'm going to assume that all Prius are like this a little bit, mine is just the extreme and within normal production tolerances. That's based on hearing from others, the many magazine testers that have picked up on the vague steering issues to varying degrees and just the fact that my alignment is spot on, no unusual tire wear or pulling and of course in spite of using the the excellent Michelin Hydroedge tires it still is not what I would consider stable.

Toyata has told me they will not help after the one and only 10 min road test they did and on my own I'll never be able to figure it out. Especially if it's some designed in flaw made worse by my car being an extreme example of the vague, non-tracking steering/suspension geometry, etc. I'm currently looking for a used Honda Civic HX because this car, as good as the technology is, just isn't all that satisfying on the freeway for me. I want a car that's predictable and more relaxing to drive and this just isn't it.

 

I feel for you Fred. I only get the wandering in the wind and on bad surfaces, so I can live with it, but if my car felt that way all the time I'd be selling too. It's a shame Toyota wouldn't do more for you, or at least take the car for the weekend to see if they could experience the problem for themselves. Makes you wonder if they really don't want to know (or maybe they already do).

As I mentioned before, if there is some endemic problem with the suspension/steering there's no way this will stay under the radar once there are a couple hundred thousand of these cars on the road, and with the production rate going up this year, it won't be that long before there are that many out there.

Sorry the Prius didn't work out for you, and good luck with your new wheels.

Geoff

 

I got my car last Tuesday afternoon. After nearly 900 miles, it has been rock solid and wander free.

I did get right behind the area of an 18 wheeler where the car got the most buffeting and while it was getting smacked it still required no correction to keep going straight.

I am most pleased, and I do believe that there must be some percentage of these cars that are having totally different handling characteristics.

 

I think FredWB hit the nail on the head when he said another Prius driver did detect something odd about his car. I do hope that Toyota is paying attention to sites like this, otherwise they'll have several hundred thousand cars out there before they clue into something wrong and a nasty interview on 60 Minutes.

I have also tried everything short of making up new specifications for alignment. I even tried changing the F/R bias so the front has 3psi less than the rear. Tried all the tires at the same psi, up to the max cold rating of the tire. No difference in handling that I could detect.

This car is not a relaxing long-distance cruiser by any stretch of the imagination. Used for its primary purpose, city commuting, it shines. With the all-season tires on snow/ice, it managed to scare the h*** out of me.

Just as Fred described, the car felt hinged in the middle, almost like the rear was trying to steer the car. I've never driven a vehicle with those sort of characteristics.

Unless somebody can recommend a magic tire - yeah right - I'm going to accept my Prius is as good as it will ever get. I don't buy this "soft sidewall" argument either. My Dunlop Graspic DS-2 winter tires have way more give than the Michelin Harmony tires, and the car tracks about the same.

I notice the difference most when I drive my parents 2003 Buick LeSabre. That thing tracks like on rails and you never feel you're babysitting something barely in control. One or two fingers on the wheel and relax.

I also find it suspicious that a lot of magazine car testers have made similar comments about directional stability. They're used to driving cars that should track nicely.

Since my Prius spends +90% of its life in city traffic at speeds under 70 km/h, I'll probably end up keeping it. At those speeds it feels normal.

 

My new 2005 seems a little unstable, but I know there is a toe-in problem, since the wheel is not straight. Another trip next Saturday might clear it up.

I can't remember where, unfortunately, but I have seen varying published specs for toe-in. One claimed toe-OUT was the correct setting, something which would make the car unstable, especially on the highway. Perhaps some dealers are using this incorrect setting, and telling you the alignment is correct.

Toe-out makes any side gust or weight transfer self-amplifying. The idea of toe-in (in other words, the front of the tires closer together than the back), is to combat this. The car will be stable when driving straight with no lean. However, when you are pushed to the side (either by weight transfer in cornering, or by a wind gust), the greater weight on the outer (turned-in) wheel makes the car self-steer back to the original course.

This is a matter of degree, and there is no mathematical formula-- it depends on the particluars of the car. The manufacturer finds the best compromise setting that achieves the desired stabillity without causing tire scuffing from too much toe-in.

Again, I wish I could quote the source of the toe-OUT claim. Anyone else seen this? I lack the official manuals-- can someone quote those directly for us?

 

I'm sure this has been mentioned before but since I am at work I did not have the chance to read thru all the replies to this post...But just in case it hasn't....

I noticed the same problem on my Prius. The car is very sluggish on center while driving on the highway. I also thought the Prius was out of alignment when I got it. I took it in and had Toyota check it out. Sure enough it was out of alignment pretty badly. I don't recall the exact numbers but it wasn't good.

So there are two issues that I have noticed with mine. Out of alignment, which was fixed with no problem. And sluggish on center while traveling highway speeds. It seems like I am always fighting the wheel to keep the car going straight.... Anyone else notice this problem or am I off my rocker?

Hope this helps.
Ryan

 

Toe-in is what you want. The spec calls for 0.0 +/-0.2 deg of toe in. That's a range of -0.2 to 0.2 deg. My car is somewhere aroung 0.1deg on both sides. It's actually 0.04" and 0.05". In inches the spec is 0.0" +/0.08" Although as received the car did have negative toe-in on one side, it's never been that way since. There wasn't any dramatic effect after getting it right, just a bit better.

As far as the steering wheel not being straight when going straight....that is not an indication of incorrect toe-in but of the steering wheel not being centered. Apparently it's extremely difficult to center the Prius steering wheel exactly. Mine is perfect not, but it took 6 or 7 tries for the dealers and various "expert" shops. I don't know why.

 

Here are my photos of moving the front air dam forward. BIG improvement in stability.
Drill a 3/16 hole in the air dam 6 1/8" from the outside hole. Attach to existing 10mm screws below fog light.

 

I recently purchased a 2003 with 20k miles and notice the same problem only on the highway with the rain groves. In 2001 I wanted a Prius but could not afford one. The local Toyota dealer had one that was part of their rental fleet so I rented it for 3 days and fell in love with the car. I remember that it too had this problem.
I truly believe it might be the tires. The reason I say this is that I have a 65 Mustang and put a set of tires on it that had the same problem. I immediately returned to the tire dealer and changed to Michelin and the problem went away. When I mentioned this problem to the tire dealer he said that he had experienced simular problems over the years and it was related to the tires not the car.
I will be interested in what you find out.

Pat

 

Well, I just got my Feb 2005 Prius's alignment fixed today according to TSB. It was drifting 2-3 degrees to the left which required holding the wheel to the right. Now I have to relarn how to drive again.

Although this car seems shiftier than my Civic, I'm wondering now much is it really the car and not really the driver.

I mean sure it's soft suspension, and it really picks up cross-winds because it's so high profile, but my Prius usually tracks straight if I let the suspension jiggle and not try to be heavy on the correction when a truck blows by. The electric steering at highway speeds tends to be overpowered so you overcorrect. Just hands off the steering wheel and notice drives straight. Angular momentum (gyroscopic motion) keeps the wheels going straight ahead.

You are also sitting higher in the car and tend to experience motion more drastically than other cars. If you lower your head/seat and/or sit lower, you will experience less motion, although certainly not the recommended position.

But, I'm also wondering if it's because this car drives more like a MR (mid-rear) than a FF (front-front) or FR (front-rear) that most people are used to. A MR will tend to turn more around the center of the car than say a FF like most Hondas for instance, and not quite like a chariot as FRs are. So once you can center yourself in the car, steering shouldn't be so strange. Maybe a test-drive in a more MR-like roadster to compare your experience?

I usually drive two-handed anyways on a long 100-mile commute everyday and it hasn't been that much different. The only thing that bugs me is how HARD the steering wheel is compared to my Civic after an hour. :| Adding something to soften the grip would just make it fatter which I don't need.

 

NuShrike,
You pose a legit question. Since I've raced SCCA Solo 1 in Spitfires, Jensen Healeys, & Trans-Ams, driven Formula Fords at Sears Point, driven national class karts, and even run superbikes at Laguna Seca I don't think I'm overdriving the car. My last truck was F250-SD long bed extra cab with a shell, so I have some reference for cross winds and sitting up higher. Others here have even more driving experience and have the same experience (only in SOME cars).
Move your front spoilers forward, It'll make a huge difference (and take only 15 minutes, you can move them back if your don't like it). Go look at the new corvettes, they have a duct to reduce air pressure build up in this area.