Poor Self Centering Of Steering Wheel 2010 Prius

[tore]

Hello from Norway to all Prius friends!

I have recently become a proud owner of a 2010 Prius Executive with LED, leather seats and Navi. During my initial testing of the car, I have found a strange behaviour of the "self centering" ? of steering wheel after a small movement especially to the right direction.

It feel`s like the steering rack is somewhat binding ?, or maybe some issue with the EPS system ? However, this is mostly noticeable when turning the wheel very little and then it seems not to go back to center properly. When steering in opposite direction , the self centering works more normal and is centering more correctly.

Today I took my car to the dealer and the garage manager also noticed this when testing my car.

However, after a test drive with the dealer`s demo car, we found a similar behaviour of this vehicle as well, so garage manager believed this to be a "product standard" as he claimed.

I find it hard to believe that this can be a Toyota "standard" as I have not notice this when testing other Toyota models with EPS system, and I canot believe that poor straight forward driving on the motorway will be accepted by the customer. All time you must make corrections of the steering wheel to keep a straight forward line.

The behaviour is almost same when doing high speed ( 50-60 mph) as in lower speed. I just changed from my original Michelin tyres ( 215/45/17 ) into winter tyres ( Conti 5 195/55/16 ) but i felt the similar behaviour before changing tyres.

Anyone else in forum with a similar experience ??

Kind regards from Tore

[Chris Dance]

Hi tore,

What you describe seems weird. I do not have a Gen 3 Prius (mine is Gen 2) but I think the steering wheel should self centre. I have never heard of any cars steering wheel which did not self centre unless there is a fault. See what others say on this forum but if it was my car I would not be too pleased to hear you have to put up with it.

Regards Chris.

[gs500ey]

Self centering is due the angle of the dampers and steering basic elements (sorry if my technical english is not very good) If you look a motorcicle and see the fork very vertical, this direccion will not self center and the bike has a nervous direccion easy for curves, but if you look to a harley with a big angle in the fork, that will self center. In a car happens the same so if the manufacturer wants a car with a direct and fast direccion to take curves easy the direccion self centers poorly and the opposite for big angles. Also cars with a limited slip differential have poor self centering.

[tore]

Self centering is due the angle of the dampers and steering basic elements (sorry if my technical english is not very good) If you look a motorcicle and see the fork very vertical, this direccion will not self center and the bike has a nervous direccion easy for curves, but if you look to a harley with a big angle in the fork, that will self center. In a car happens the same so if the manufacturer wants a car with a direct and fast direccion to take curves easy the direccion self centers poorly and the opposite for big angles. Also cars with a limited slip differential have poor self centering.

Thanks for your comments and explanations.

Being an automotive engineer with almost 30 years experience from the car business, I agree with your viewpoints. However, this is my first experience with a Prius car, and I find it a bit weird compared to other cars I have driven. I realize that the little Mac Pherson Caster angle will make the car less stable straight forward driving and maybe better in curves, but my point was the fact that the self centering is ok when turning the steering wheel a little to the left side, but poor when turning the same amount to the right side. So this I tried to explain to the Toyota garage manager, but as their demo car proved to have the same symptoms, this had to be a " standard feature" for 2010 Prius he claimed. Though, he admitted little knowledge of the new Prius...

What if the wheel angles are out of spec. on the dealer`s demo car as well as mine ?? VIN no is very close to my VIN... This was my question to the dealer....

The answer is still "blowing in the wind..."

[Chris Dance]

Hi tore.

Did a reasonably long run today in my Prius T Spirit Gen 2. The steering was fine and self centered all the time. I tried to reproduce what you have said your Prius does but no matter how small a turn I did on the steering wheel it self centered.

Hope this helps.

Regards Chris.

[tore]

Hi tore.

Did a reasonably long run today in my Prius T Spirit Gen 2. The steering was fine and self centered all the time. I tried to reproduce what you have said your Prius does but no matter how small a turn I did on the steering wheel it self centered.

Hope this helps.

Regards Chris.

Hi Chris and thanks for your testing of the steering abilities of your gen. II Prius and your feedback.

However, as for the gen III Prius, I have not seen any comments relating to this issue, neither in this forum nor in Prius Chat ( US forum). I have posted my requests in PChat but so far no comments from other gen III owners who could verify if this is " production standard" or not.

So I will have to find a different dealer in Oslo area and test one or two other cars next week. Maybe I will figure out more in due time..?

[tore]

Just wanted to bring up this issue one more time, in case someone could give me their experience from a gen 3 Prius..

I have tested 3 different gen 3 models, and the mentioned symptom was similar on those car as on mine.

When turning the steering wheel a little to the right ( maybe you must try the opposite direction) the SW does not come back to the center position when released.The SW will continue to stay a bit offset to the right making the car to continue the right turn after being released. I find this very strange based upon my experience from other cars with electric powersteering.

So, if any of you could just try this while driving on a normal straight forward road, and give a feedback in this forum, I will be very happy.

I have a discussion with my dealer as for this issue, and I would like some comments from other Gen 3 owners.

Thank you !

[Fujisan]

I have a discussion with my dealer as for this issue, and I would like some comments from other Gen 3 owners.

Thank you !

I am sorry, I must have missed your orginal post.

Right, self-centering, erm, really haven't noticed anything wrong. Seems the same to the left and to the right. No binding or anything that feels strange.

On the motorway, it doesn't particularly like strong cross-winds, but it's not the worst car I've had for feeling nervous in those conditions. Otherwise, it keeps a straight line on the motorway.

Sorry I can't be of more help.

[Sagitar]

Self centering is due the angle of the dampers and steering basic elements (sorry if my technical english is not very good) If you look a motorcicle and see the fork very vertical, this direccion will not self center and the bike has a nervous direccion easy for curves, but if you look to a harley with a big angle in the fork, that will self center. In a car happens the same so if the manufacturer wants a car with a direct and fast direccion to take curves easy the direccion self centers poorly and the opposite for big angles. Also cars with a limited slip differential have poor self centering.

I have only just noticed this thread. In November I put on a spare set of wheels with winter tyres and at the same time had a full geometry check done on the car.

One of the things that I discovered was that the caster angle on the Gen3 has been increased when compared with earlier versions. On the earlier model (Chassis type NHW20) the caster angle was three degrees and ten minutes. On the latest version (Chassis type ZVW30) the caster angle is five degrees and thirty five minutes. That change ought to increase the strength of the self centering tendency as compared with earlier versions.

The only other significant issue revealed by the check was a small error in the toe angle of the right front wheel. It should have been zero degrees plus or minus six minutes and it was actually measured at thirteen minutes. It was corrected and I cannot say that I am noticing any real difference in the steering behaviour as a result, but it does make the point, that even on a new vehicle there may be geometry errors.

I have no problems with the steering on my car; it steers and self centres very nicely.

It could be worthwhile to ask for a geometry check if you have doubts, but part of the problem there is to find someone with the equipment and the trainging to do the job competently.

[tore]

Self centering is due the angle of the dampers and steering basic elements (sorry if my technical english is not very good) If you look a motorcicle and see the fork very vertical, this direccion will not self center and the bike has a nervous direccion easy for curves, but if you look to a harley with a big angle in the fork, that will self center. In a car happens the same so if the manufacturer wants a car with a direct and fast direccion to take curves easy the direccion self centers poorly and the opposite for big angles. Also cars with a limited slip differential have poor self centering.

I have only just noticed this thread. In November I put on a spare set of wheels with winter tyres and at the same time had a full geometry check done on the car.

One of the things that I discovered was that the caster angle on the Gen3 has been increased when compared with earlier versions. On the earlier model (Chassis type NHW20) the caster angle was three degrees and ten minutes. On the latest version (Chassis type ZVW30) the caster angle is five degrees and thirty five minutes. That change ought to increase the strength of the self centering tendency as compared with earlier versions.

The only other significant issue revealed by the check was a small error in the toe angle of the right front wheel. It should have been zero degrees plus or minus six minutes and it was actually measured at thirteen minutes. It was corrected and I cannot say that I am noticing any real difference in the steering behaviour as a result, but it does make the point, that even on a new vehicle there may be geometry errors.

I have no problems with the steering on my car; it steers and self centres very nicely.

It could be worthwhile to ask for a geometry check if you have doubts, but part of the problem there is to find someone with the equipment and the trainging to do the job competently.

Thanks for the comments.

I have to add that I have been testing 4 different dealer`s demo cars from august/september 2009 production, and all have the similar sensation...when driving straight forward on the motorway and turning the steering wheel maybe 10-15 cm to the right and then releasing, the SW will not come back to the center position by itself, but I must turn it manually.

If I turn the SW more for sharper turns, selfcentering works, but the SW will not come back to center pos. by itself and I have to manually move the SW the last 10 cm to center position. For left hand turns, all is working normally, however.

But, based upon the fact that 4 different cars all have the same sympthom, I understand the reason for Toyota`s unwillingness to admit this to be a problem. However, based upon comments from other Prius 3 owner`s both in this forum and in Prius Chat, I still believe this to be abnormal, and maybe caused by wrong geometry settings from factory for the first production vehicles . I will continue to push my dealer and make them do a wheel/suspension geometry checking.

[madzel]

I have exactly the same problem in my car.....Have you ever managed to fix it? How did that case and up?

[Jan&tone]

No problems on mine! However, I do believe that what you are describing could possibly be caused by a slight difference in tyre pressure, more pronounced at low speeds and slight turning... Probably not noticeable if you keep your hands on the wheel!

[Doesn'tExist]

No problems on mine! However, I do believe that what you are describing could possibly be caused by a slight difference in tyre pressure, more pronounced at low speeds and slight turning... Probably not noticeable if you keep your hands on the wheel!

+1 I was thinking that. And I've also noticed that on all 4 tyres the pressure is going down more so than any other car I have owned. I feel like I need to check the Prius every other week .

[kithmo]

Could it be the camber on the road ?

[Seamaster73]

If it's pulling to the right in Norway, it could well be camber.

[Jan&tone]

So between the camber on the road and a slightly soft front right hand tyre the centering is solved

Next!

[kithmo]

In my experience with previous motors I have noticed that when the toe-in is set to zero or toe-in angles then the car does tend to follow camber and grooves in the road more readily, whereas cars with toe-out settings tend to want to go straight on. This is by no means a scientific fact, just what I have observed over the last 38 years. The prius is probably set to, or near to, zero to achieve less rolling resistance at the expense of handling IMO.

[Sagitar]

In my experience with previous motors I have noticed that when the toe-in is set to zero or toe-in angles then the car does tend to follow camber and grooves in the road more readily, whereas cars with toe-out settings tend to want to go straight on. This is by no means a scientific fact, just what I have observed over the last 38 years. The prius is probably set to, or near to, zero to achieve less rolling resistance at the expense of handling IMO.

The target data for the ZVW30 chassis (i.e. the Gen3) is: front toe nominally zero with a tolerance of plus or minus 6 minutes; rear toe nominally 9 minutes with a tolerance of plus or minus 8 minutes. I had mine checked soon after delivery in 2009 and the right front wheel was well outside the specified tolerance. When I had it checked again a year later there had been no movement at all in the front toe. The rear toe had changed a little but was still well inside the tolerance.

I can't say that I have noticed any particular tendency for the vehicle to tram-line, whereas the Lexus IS250 that I had before it was very prone to do that initially. It was cured by correcting the geometry. I tend to conclude that dealer staff have neither the equipment nor the skill required to check and set up the geometry properly and that it is worth finding a trustworthy specialist firm if you have a problem. I don't see a lot of postings about Prius geometry problems or uneven tire wear so I have tended to assume that it is not generally an issue?

[r04drunner1]

If it's pulling to the right in Norway, it could well be camber.

I do think it's the camber as well.

I checked on UK roads and noticed the tendency mentioned, but in the opposite direction (i.e. towards the left). However, when I was on a road with opposite camber (a sweeping bend) I checked and the tendency was the same as the Norway car.

I therefore concluded the slight difference in self centering is due to the camber in the road. That would explain why it was noticed by the OP on several different cars.

It's difficult to get a long enough area of truly flat surface to fully test this theory. If you could find a big, flat carpark somewhere and a late night when nobody else is around, you could try to see if the effect is cancelled (or the same in both directions of steering). However even car parks usually have camber and/or a slope, to help with drainage.

In conclusion therefore, I would test the tyre pressure (because that's generally a good idea anyway), but everything else seems to be within normal operating parameters, so I wouldn't be too worried.

Hope that helps.

R04drunner1