Twitchy steering at freeway speeds.

You could always call TRD and see if they'll sell you some of the mods they put on the Prius race car. Here is some of the changes they made to make it track ready. Sounds like the race team tried to fix a lot of the body roll / cornering issues.
http://www.caranddriver.com/article.asp?se...2&page_number=1

"The difference is under the body. First, the spring rate was upped 15 percent, and stabilizers from the Euro-spec model were employed. The shock absorbers were stiffened, and the rear-control-arm-and-bushing geometry was modified for flatter cornering with less body roll. At the front end, the steering-knuckle joint was reinforced, and special high-performance Bridgestone Potenza RE050 rubber (195/55R-16), boasting a stickier compound than on the standard model, was fitted all around."

 

To FredWB and MikeN. And all others interested in this touchy steering problem. I posted before when this subject came up. As others have said, they do not have any problems with their steering and they don't understand what the gripe is. Exactly my point. We HAVE experienced this particular problem and we want our cars to be like your cars, without the steering problem.

I noted this problem to the dealership within the first week I took delivery because I wanted it on the record. The service manager and I decided to ensure that the tires had the correct pressures and that I would drive the vehicle for a while to see if the problem persisted. At 5400 miles it is still there, but slightly lessened.

Just for a little background, I have been driving for over 30 years, I have owned 20+ aircooled VW beetles and busses, also Golf + Jetta. I know light and twichy, and crosswinds, as well as headwinds. I drive a Ford E350 Turbo Diesel for work and have logged 120,000 miles on it. I have also had other cars too. I know how these handle when they are in good condition and bad condition.

Another point. We rented a 2004 Prius for 3 days and drove it all over to see if this was a car that we liked and how well it was made etc. It did not exhibit this steering problem at all, I certainly would have noticed it, it is that obvious. If I can try to describe it again: Driving straight ahead on a straight stretch of freeway, the car will begin to veer steadily to the left or right. If even the SLIGHTEST correction is made, the car will begin to veer steadily in the other direction. It does not want to find a "sweet spot" right in the middle as so many other cars do. I have noticed that the "drag" on the steering wheel is the same throughout the middle, (straight ahead) range. I seems that the stiffness of the geared rack is stronger than the return push from the front end trying to find center with its caster and toe-in.

Enough ramblin' any thoughts?

 

Tom, very good summary and that is exactly my problem. Toyota sent out their expert and pronounced the car just like all the others. But another engineer owner drove mine and said it is different from his. On uneven roads and cross-winds it borders on dangerous in my opinion and I've owned lots of cars since I started driving in 1965.

Fred

 

Fred, Thank you! for your reply. We are driving from Cleveland to the top of Michigan this weekend, another good drive I will post a condition assessment of the steering when we return. We have already been down to Charlotte NC (and averaged 51mpg on that trip).

I took it in for the first service last night for the 5000mi. oil change and tire rotation. The dealer I bought it from has their own method. They want you to come in at 3750mi. for an oil change at $29 and then come in at 7500mi. for an oil change and tire rotation for $80.....at this 5000mi. point they just changed the oil.....they said that they worked out this system with Toyota. Just throwing this out for comparisons.

Best, Tom.

 

I'm originally from Cleveland too Tom. NE side of town. Yeah I can't fault the mileage although lately I've had trouble keeping it above 48 or so. The traffic around here is so bad and hills don't help. I know that my cars steering is not me. I just go back to my wife's RSX if I start thinking that to remind myself what tracking is all about. My Prius on the other hand seeks. And I swear that it pulls left coming to a stop but the alignment has been check half a dozen times now. The steering wheel just feels heavy almost wanting to go left but not quite an abrupt pull.

I plan to have the tires rotated when I take it in for the recall and see if that has any effect. If I knew of a tire that would not hurt mileage and improve handling I'd go try that. I may just finally give up and sell it because my wife will not share the driving on trips as she's too scared of it now. And it does tire me out correcting it for hrs on end. You just can't relax for a second with it. I should have kept my crx-si. It was a 1990 and in perfect condition. And even it handled better than this. And I got 30 around town and 36+ on trips.

 

has any one with the twitchie problem had a 4 wheel alignment done on their car? It's entirely possible that someone in the service dept. jacked the car up on the rear axle instead of the jacking point just behind the rear axle. If the rear is tweaked out of alignment from the front it'd make the car unstable at higher speeds. Those of you who have this problem and no remedy from Toyota I'd find a good shop and get a 4 wheel alignment done. If that fixes the problem, small claims court here we go if the dealer won't compensate you for the alignment.

 

The dealer has tweaked my alignment 4 times now and I've been to two independent shops. It's pretty close, although the last shop said the right camber was out from the left but both are in spec. They did say they could tweak this but it should not be causing this. I really suspect a bad tire and another Prius owner has offered to twitch all four tire and wheels with me. If I don't decide to sell the car first I might do that. This is all just so time consuming for me and frustrating. I drove it today and really tried to take a light approach and give the car it's head somewhat. It will go straight and then suddenly follow a road groove or a gust of wind. The slightest correction and you start this instability cycle of back and forth mostly within the lane but often right to the edge of it. And it really feels like it's the rear of the car too. So I'm going to at least rotate the tires and see what that does before I consider swapping all four with my friend.

And suddenly to make matters worse I'm having the toughest time lately keeping the MPG up. It's right at 46 now for 1/4 tank when I was approaching 51-52 about a 1000 miles ago. I know there could be lots of logical reasons for this but it hasn't made me love the car all that much lately.

 

if your going to swap tires with another Prius, just a suggestion and if you think the problem is caused by one tire I'd start with the right front and then the right rear and on to the left side and do only one tire at a time to be able to find the problem tire. Yes I know this will take time but will eliminate 3 tires causing the problem. Just a thought. One other thing before you go the tire route, cycle the steering wheel from lock to lock several times just to eliminate any crud build up in the electronics for the steering.

 

Thanks Frank, good suggestions although I don't reallly think it's the power steering like some say. My guess is something in the rear end of the car because that's where it feels like everything originates. Another friend (local) with a Prius and the same problem just sold his for around $24,500 I think, package #7 and right away too. He tried getting the dealer and Toyota to do something. He's another guy that has been around cars awhile and didn't buy the excuse "it's the power steering" and some notice it and some do not. You would have to be asleep not to notice this.

 

well you've been around this forum for a long time and you know that this problem was also prevelant in the Classic and my thoughts are two fold
1) this could be a strain guage problem in the rack. I don't doubt this for a minute.
2) the rear axle assy isn't some nomal thing is a twist beam and if it's not in perfect alignment it'll wander all over the road like a drunk.
I think I would have a 4 wheel alignment done by a (the best in town) private shop and when it's all to the tightest specs, not just in the middle of the range and when the left and the right sides are exactly the same reading and the alignment tech say's that should be right, the get him to take it for a road test at a speed where the problem is and then have him or her say they're satisfied that it's perfect, if it's still a problem then make some more adjustments to fix it. My alignment tech is a race car driver on the weekends and has always been able to correct some nasty driveability problems, one really bad Ford Econline van that was so squirelly (sp) as to be a hazzard to all the traffic on the road, Ford said it was fixed several times and finally had him drive it and he bent in another 3 degrees of caster and it was like on rails. There are good alignment people out there, who know how to do things that aren't in the "book". If a 4WA doesn't do it I'd tell Toyota to get the Zone Rep down and have a talk with him and explain it to someone who has the power to change out the rack. Your local service manager is just a firewall for the Zone Rep and I'd burn thru him to the Rep.

 

Twitchy--no "sweet spot"

Just a thought: Since the steering will drift to either side at high speed, and won't find a sweet spot, try checking out the caster adjustment in the wheel alignment. I believe this has a significant effect on steering stability. I believe some US mfrs. had started phasing out adjustable caster some years ago, and often produced poorly assembled front ends that couldn't be corrected.

I wouldn't expect this from Toyota, but some shops may take caster settings for granted when doing alignments.

 

I have had the car to two outside shops. The last one did the alignment the old fashioned way without the aid of a computer. He did say the camber on the right frt was out from the left and he could correct it by slotting the tie rod. But he also said that the car felt OK to him on his road test, much better than his Ford Focus. Although he came highly recommended I'm not sure that Ford Focus handling is my ideal. I've seen the toe in numbers and they're about .04-.06 right now with little difference from left to right. I have one more shop to try that was also recommended. But the car has been in for about 6 alignment checks, 4 at the dealer.

I did get the Toyota Rep involved and he didn't even bother to talk with me about the car in spite of my waiting around for him (he was two hrs late). He took the car for a 10 mile freeway roadtest and prounounced it "normal. I had been waiting over 2 weeks for this review of my car. I had planned to take him on the section of road at maybe 70-75 where it really becomes a handful. I think if you drove it and there wasn't any wind or bad road grooves or nearby cars you might think it was light steering but acceptable. It's the car's eargerness to move around with outside side forces where you really start to notice things. And the higher the speed the easier it is to see that there's something not right. My friend that owns a 2004 drove it for several miles thinking it was OK when suddenly he began to notice that it didn't behave like his car. His son passed us and his car looked rock steady just ahead of us while I could feel the back end of my car wiggling even in the passenger seat.

I wanted to convey all of this to the Toyota Rep but was not given the opportunity to do so. Toyota appologized when I complained and gave me a a $150 voucher for my trouble. What good is that if my car doesn't feel safe to me or others. When I said to my service writer I wonder what I should do now because I still don't feel safe...his reply was "Find another Dealer". I have never given him cause to treat me like that. I've always been in control and respectful of him. Even when they damaged my car during one of the alignment checks I didn't loose it. I won't be going back to Kearny Mesa Toyota again for sure.

 

I drove from Cleveland to the U.P. of Michigan this last week, 1000 miles at freeway speeds of 60-85 sustained.

Continued to experience the steering wander/pull.

A few thoughts:

Speaking of "perfect alignments", when I worked on Jaguar cars in the early 1970's we had to put 100 lb. sacks in each seat BEFORE setting the front end alignment...

Our Prius cars are unique in that they don't have a steering wheel lock like other cars. As a test, with the car parked, I put my fingers on the area where the rack bolts to the car chassis. My assistant worked the steering wheel back and forth, in the center area and lock to lock. The steering rack to chassis interface is with rubber bushings and bolts. The rack moves 1/16-1/8 inch up and down in relation to the frame as the steering wheel is worked back and forth....

Does anyone know if there is a relationship between the electric power assist and any computer controls? I do not have the manuals but that may be the next step to understanding the mechanics and what is possibily going on.

To Frank Hudon, could you explain the "strain gauge" idea on the rack?

 

The strain guage is an electic resistor unit that is connected to the steering shaft and the shaft is connected thru to the pinion shaft in the steering rack by a torsion bar. One part of the strain guage is connected to the steering shaft and the other to the pinion shaft. As the steering wheel is connected to the steering shaft, when you turn it you actually subject the torsion bar to a twisting action and the strain guage measures the amount of twist and being connected to the steering computer, calculates the amount of power the stepper motor has to provide to give you "power steering". The stepper motor is geared to the pinion shaft in the rack and if I'm not mistaken there is two strain guages one for turning left and one for turning right. Sorry for not getting back sooner. Life! it sometimes intrudes.

 

I have had this same steering condition on my Prius made Jan. 2004. It appears that I need to constantly correct it to keep the car to go straight ahead......there is minimal center feel on the steering. However, if I let go of the steering wheel the car tracks straight so I did not think there was anything wrong with the alignment even though my steering wheel was slightly off center. I took it in to the dealer, and told them of the twitchy steering and off center steering wheel and they performed an alignment...apparently the camber setting was off slightly. This seemed to help a bit but I still had the twitchy steering.

Well, here comes the good news at a cost of $500 :-( After encountering a wet spot on a freeway on a slight overpass turn, my Prius slid pretty badly. I started doing some research on the Goodyear Integrity tires and found out that the general consensus is that it is a lousy tire...some even call it unsafe as the tire loses traction very quickly on wet and even dry roads. After doing my research, I replaced the tires which had 7,000 miles on with with Michelin Hydroedges. What a difference! The steering is no longer twitchy and the on center feel is improved (but still not great). Tire noise has not changed and the handling has dramatically improved to the point that I can take turns without compromise. The handling improvement has brought a smile to my face (note that my other car is a Mini Cooper S -- so I know how a great car handles

I hope my experience helps with some of you that are encountering the annoying twitchy steering problem.

 

So do you have enough miles on the new tires to say how the gas mileage was affected? I'd be interested in the how it is after say the 2nd tank where the tires have been run for awhile. Yes I do know that the Integrity tire is a very low rated tire compared to some of the better ones. But I've been afraid of loosing 5-10% in mpg. I'm struggling to keep it above 48-50 here in San Diego so if it were in the mid or lower 40's beccause of a tire change it would really upset me.

But I have long suspected the tires as the cause of this since I've had other cars (RX-7) that did the exactly the same thing and were night and day with just a tire change, nothing else. It could even be that most of the Integrity tires are OK and that there are a few defective ones. It's not really a horrible tire, just not a great one from what I've heard. So I'm leaning towards a defective tire maybe.

The hydro edge tire is a bit extreme for me here since we have had so little rain over the years. Maybe the Enegy MXV4 plus would be a better choice and lower rolling resistance too. Anyone have any experience with this?

 

I have approx. 1200 miles on the Michelin Hydroedge's. I have not noticed a decrease in my mileage which I averaged 48-52 on a consistent basis (before the new tires and after). I live in LA and the key reason I bought the tires were for correcting the steering twitchiness and increasing the very average handling of the Prius. This is a good tire choice as well as the Michelin Harmony (very low noise level, very comfortable, and pretty good handler).

By the way, the comment about the Integrity tires being defective. If there are defective ones, I find it hard to believe that there are so many defective ones out there....just the TireRack reviews and 1010tire reviews points that it is a bad tire. Anyway, for those of you that want a fix you may want to consider changing tires if the steering vagueness and the poor handling bothers you.

 

Thanks for that update. I did see a lot of postiings of others with the Hydroedge that complained of 40-50 miles less per tank. It did get me worried but as we both know, they could be driving faster because the tires feel that much better. I was trying to give those people that say the Prius doesn't twitch and handles like a dream the benefit of the doubt when I said maybe it's defective tires.

This has been a tough issue for me because there are those that say the Prius handles perfectly and tracks well. And then there's the minority of us that say it's about he worst car for tracking except when we've had cars with problems. I've owned a bunch of cars, all lighter than the Prius too, that all tracked better, much better. My experience on roads back east for about 7 yrs and maybe 32 years in San Diego tellls me that no one is going to convince me that my Prius is right and handles superbly.

I'm not expecting sports car perfomance. I just don't want to feel that I can't take my eyes off the road for even a split second without the car drifting around on it's own. Thanks again for the feedback. I'm not sure if the Harmony will cure this problem like the Hydroedge tires might so maybe I should just try the hydroedge tires. Those cross grooves for water are probably also what help it track better.

 

I've been watching this thread with the hopes that someone would one day report the secret to stable freeway tracking. I too have experieced this effect, right from the moment I picked up the car from the dealer and drove the 20 minutes home, all highway miles.

In addition to others here, I have and do own ultra high performance sports cars that are far lighter than the Prius and they all had spectacular stability in crosswinds, traffic and over irregular surfaces. Since they also had amazing suspensions and ultra-high performance tires on them, I have not compared them because its just apples vs. oranges.

What I did do is to correct the tire pressure per the Toyota manual. This helped a bit (probably because they were all at different pressures and nothing was close to factory spec) but not enough for me to forget about it.

Not wanting to replace the tires, I tried something less challenging and raised the tire pressure two months ago. The fronts are set to 44 (max cold pressure for the Integrity) and 42 rear so I could keep the 2lb front rear differential this car needs.

The twitchy feeling is all but gone. The car now tracks straight if I let go of the steering wheel and I rarely get the sense that the steering has any twitchiness.

Its not a perfect solution but if it helps anyone else out then its worth posting.

Since this worked so well for me I have got to believe that the issue is a tire problem. I previously discounted the alignment as being the primary issue since that didn't help anyone else's car.

In order to help me choose a replacement tire, I stepped up my tire research (it actually started 6 months ago since I knew that the Integrity wasn't a stellar performer and I would want to get something much better at some point) and wound up talking to Michelin.

It turns out that Michelin is quite tight lipped about which of their tires is a low rolling resistance tire (LRR) which is standard on the Prius and contributes a few MPG to our stellar gas mileage.

Its not really a state secret which of Michelin's tire is their LRR series (its the Energy series) but I wanted them to help me find the ultimate Prius tire. After they told me that rolling resistance is proprietary, I called them on their BS. This is like selling a Prius and saying that we won't tell you what MPG its rated at for because it will divulge our technology secrets. I now wish that had taped that conversation. The comedic value alone for you guys would have been the effort. We'll get back to you is all the nervous Michelin woman said to me.

A month later I received this email:

From [email protected] Wed May 5 09:39:31 2004
Wed, 5 May 2004 08:56:03 -0400
Received: from hub-gw.us.michelin.com by oncmh1.onc.michelin.com
X400-Originator: [email protected]
Date: 05 May 2004 08:58:53 -0400
From: Michelin-NG02763 Webtire <[email protected]>
To: [email protected]
Subject: Reply From Consumer Relations

Thank you for revisiting our Web site.

The MXV4 line is considered our most energy efficient tire line and for that reason carries the name "Energy". However, rolling resistance is a consideration in all of our tires and therefore, it would be inappropriate to advertise one line being exceptional.

If you have additional questions, please respond to this email or you may call us at 1-800-847-3435 (toll-free) between 8:30AM and 6:00PM Eastern Time Monday through Friday to allow one of our Consumer Relations Representatives to assist you.

Michelin North America
Consumer Relations Department

(Please Do Not Delete the line below.)
Email ID: 1134578

OK, so they sort of/almost admit that the Energy series is their LRR tire (it really is, go look at the old Car & Driver road tests when it was released). This wasn't enough for me. I went on and researched a few more companies, just in case.

The Michelin MXV4 Energy is a very good tire. I have used it in my Mercedes and my wife's Toyota Cressida for years. It is standard on big Mercedes and other performance luxury cars but I wanted something with a bit faster response and crisper handling. This desire led me to Yokohama.

Simulated phone call to Yokohama (this actually occurred via email - humor me, please

Hello this is Yokohama USA, how may I help you?
my name is Bob and I am looking for an ultra high performance tire that has low rolling resistance for my 2004 Prius.
Why sir, did you know that there are other factors that affect rolling resistance?
Really? Like what?
Sir, your driving style will affect rolling resistance!
No it won't.
Yes, it will.
No it won't.
Sir, are you an engineer or something?
Yes I am.
How long?
30 years.
Sorry.
No problem, would you just find me a tire that I would be happy with? You see I have used the ultra high performance Yokohama AVSi on my Lotus for 15 years and its fantastic.
OK sir, hold on a moment.
Sir?
Yes?
The tire you want is the Yokohama AVS ES-100
You have an AVS tire that is low rolling resistance?
Yes we do!
That's fantastic Thank You! Maybe I'll really love it and tell all the guys in my club (Priuschat) about it.
That would be fine with me sir.
I have another question.
Yes sir I would be happy to help.
What is the actual rating for rolling resistance. I mean the SAE figure for the coefficient of rolling resistance.
What's that?
Just ask your engineers, they already know what it is, I would just like to know the number.
I'll do that, would you mind calling back tomorrow.
Sure.

Next Day:
did you get that figure for me?
Sir, what was it again?
The rolling resistance value of the ES-100. You see I already know what it is for the Michelin MXV4 Energy, and I would like to compare the two.
Oh yes I remember. No, I haven't found it yet. I'm having a hard time explaining it.
You mean that you would tell me if you found out what the number was?
Sure, I would tell you.
How about if I emailed you a report that talked about LRR tires, talked about the SAE tests and gave values for some popular tires, would that help?
Yes, please send it.
Done.

A few days later.
Did you get the report?
Why yes I did. Thank you sir, it was interesting.
Did you get me the number?
No, I didn't
How long will this take?
Don't call me, I'll call you.
Oh, I see. Bye.


I have not given up and am also in contact with several other companies. This way we can all have a better choice and still use LRR tires. Will I switch to the Yokohama or the Michelin (or the Nokian or the Toyo, etc.) Yes, but I want to wear out the Goodyears first. They are acceptable enough at 44/42 so they will have to earn their keep for now.

If any of you switch, please keep us apprised of your experience.

Thanks,
Bob