New Tires, size, brand, and results?

As some of you know, I guess I've been the most vocal person about the tendency of MY (note: not all) Prius to wander around at freeway speeds. After trying to get Toyota to help (4 alignment tweaks and a quick check by a factory rep) and two checks by outside shops I think I've finally come to the point where I've got to try a new set of tires. My car originally had some negative toe-in on the left side which has been corrected to about .05 deg both right and left. I've also corrected a camber difference where the left was -.5 deg and the right about -1 deg. Now they're both -.5 deg. Although camber shouldn't cause this it was the only thing about alignment left to correct. I've also tried all the various tire pressure combinations to no avail as well. Many have suggested something in the power steering but at this point until Toyota offers to change it out or inspect it in some way, I'm stuck with trying a new set of tires, selling the car, or just trying to ignore the problem.

So, my question is this. Who among you has replaced the tires? What size did you go with? What brand and model? And more importantly how did it affect your gas mileage? And just as important, but subjective of course, how did it affect the car's handling?

I'm only considering the 185-65X15 or at most the 195-60X15. I know some of you have gone with the larger size and I'd be interested in your long term results. I'm considering the Michelin Energy, Harmony, or Hydroedge. But I'm favoring the Energy because one owner who has corresponded with Michelin said that it's their lower rolling resistance model.

This has been a very frustrating problem for me because some of you have been so insistence that the Prius handles better than any car you've owned. And while not trying to imply that I'm imagining things, the implication is there just the same. I've also been told by some that I should suddenly have to re-learn how to drive a car because the lack tracking or dead spot for the new Prius and that I'm causing the wandering by my constant correcting. If I don't correct, the car can and will just wander right out of the lane. if the correction is too small or too slow same thing. Actually I've become quit good at making these corrections and staying in the lane for the most part, but sometimes it even surprises me.

Since 1965 and my first car, a 1955 Chevy, I've had about 35 vehicles and have never had one do this that didn't have something wrong with it. In the case of my cars it was either alignment or tires. It was never determined if it was a defective tire or just the characteristics of a particular tire. But in a few cases a different tire bad a huge difference. And although the numbers are small, there are just too many of us having a wandering problem for this to be imagined. I met another 2004 Prius owner, same color too with the same problem, parked right next to me while having my recall done last week.

Maybe it's the price I've paid for being an early buyer (Nov, 2003). So any tire feedback I can get before I run out and throw more money at this problem would be appreciated. I don't think Toyota is going to help in the immediate future so I've been trying to help myself as best I can. Thanks.

 

John I'm not sure how you missed it but there are a pretty good number of us that have been talking about this. Even a few of magazines picked up on this on their tests of the 2004 Prius. Anything over say 60 mph or so seems to do it for me and faster is worse. The car will seem to be just fine and then it will move either right or left. Without any correction I'd soon be out of the lane, into a cement guard rail or into the side of a passing vehicle. I've tried a few times to just lightly grip the wheel, point the car straight ahead and see what happens. The car can seem pretty normal on smooth asphault at times. It's like it does not have a desire to go straight for any length of time. No sweet spot or put another way, it doesn't track in a straight line well. And the constant corrections only make for more corrections because it's tough to figure out how much to correct. It's then that the soft suspension exaggerates the problem somewhat. I swear at times I feel like I'm driving a hook and ladder fire truck it can be that bad. Very tiring on a long trip needless to say.

Cross winds, passing vehicles, especially large ones, road grooves, expansion joints, crown changes all make it worse and can really move the car all over the lane and so takes constant attention and correction.

I'll just site two people I've met lately with this problem. One was Tom Sprague from the local Prius Club. He ended up selling his at about 1600 miles because he thought under the right conditions, his car could be dangerous. He's a guy with lots of car experience and a long time Miata owner/racer. I met another last week while at the dealership who had not even mentioned it to the service writer after driving it over 16,000 miles! I'm not saying it's all cars of course but there are a few of us unlucky ones out there.

I've tried up to 42/40 and have been kind of reluctant to push it to the limit. Tonight I put in 44/42 and I'll be trying that out tomorrow. But so far nothing will make this car track even remotely like our other car, an Acura RSX. And of course I realize that is a much different car, stiffer, shorter, wider tires, etc. But it's just like night and day. I let another memeber of this chat group, Henry Eisenson drive my car. At first it seemed all together normal to him but then he noticed it doing things on it's own and confirmed it doesn't behave like his car after about 8 miles. He's offered to swap tires and wheels sometime and I may try that too. I jacked up the back end and tried to find any suspension play tonight but didn't notice any movement at all anywhere.

Anyway, thanks for the feedback on your Hydroedge tires. I have heard from others that they're pretty good and track well too.

 

Whity, had the same experience with a '93 RX-7 and Yokohoma tires. Boy was that car unstable at speed! And like this car, I tried everything I could think of to fix it before I put new tires on it. It had a brand new set of tires the selling dealer had installed so I didn't even think of trying that at first. I put on RE750 Potenzas and it was like night and day. An amazing difference. The car drove like it was on a railroad track after that.

John, yes Henry E., another priuschat member, has volunteered to do just that, switch tires with me. I hate to impose on him because he is such a great guy but I might have to do it in the interest of sanity and science. He's the one that drove my car and confirmed for me that it's not at all like his. I have not driven his yet and should. I also have another friend I convinced to buy the Prius that might let me try hers. I think it would be best to just switch one tire/wheel at a time and go out and try to issolate this if possible. Today I'll try the 44/42 and see what the does for me. Maybe next week I'll try to get together with Henry. It's a lot of work but at this point my options are running out. Thanks to both of you for responding.

 

I had the same experience at Poway where I bought the car. They're so far from the freeway I would be surprised if they drove yours there. KM did fix a toe-out condition on the left front, but that did not help. I agree with everything you've said. But it's much worse with highway grooves than without. The 2004 Prius does have a lot of side area and so the side pressure loads from cross winds can really affect it more than a lower profile vehicle like my wife's RSX. Soft suspension, narrow tires and track...well you do get the point. I just hate the Prius wiggle and the car literally tilting back and forth as you go down the road. I'm just lucky I don't speed, it's much worse at say 75 mph.

Evans Tire in Poway has offered to put on the 195R50X15 Hydroedge tires. I can try them for 30 days and then get the smaller ones if I'm not happy. Seems like our best option. I'm so tired of fighting this the $500. will be money well spent if it works.

When did you get your car? Mine was made 10/03 and the last number in the VIN are 40020408. I picked it up at the end of Nov.

 

Sorry, meant 195H60X15. I think I'm going to order them today and put them on next week. I'll give them a short test up the coast next week and report back here.

 

I just posted a pic of the 195H60X15 Hydroedge tires in the appearance mod album that solved my wandering problems. I originally said that there was 42/40 in the tires but the dealer put in 33/35 and it was still better!! Now with 42/40 is even better if possible.

 

It was pretty funny when the service writer said he had never heard this complaint and right next to me was yet another red 2004 with exactly the same problem!! All he did was listen. This was a Escondido Toyota where I went for the ECU recall. The odds of that happening have to be small if this is in fact a very very small problem.

I still have to drive my car some more to know what I think but it's so much better with the 195H60X15 Hydroedge tires now. I guess it will never really track like our RSX Acura and shouldn't expect it to do so. It's just too different...soft suspension, long wheelbase, higher profile, etc. But if it was like this when I bought it I would not have been unhappy.

 

I don't know what the rim width is but the 205 size says it should fit in a min of 5.5" width rim. They're slightly less rev/mi, while the 195 size in 60 series is slightly more than the stock size. They should work if there isn't some sort of clearance problem. I'm sure you'll loose a little more mpg's of course. I' think I'm seeing about a 2 mpg loss but it's too early to tell with only 60 miles on the car. My addtional impression is that the wandering freqency has been reduced and the amplitude decreased. The response to outside forces, side wind load, grooves is just so much less. And the car sticks in corners now and never ever squeals. But I still won't say the car "tracks". It's just a lot lot better.

 

My build date is 10/03 and I picked it up in Poway CA 11/28/03.

I'd just be careful not to go too overboard with the tire width. Unfortuneatly I can't say if the std width, 185 is as good. But the tires look fairly wide at 195 and feel really good in corners too. I just don't think the lack of absolute "center" will ever be a characteristic of this car like it is for the RSX Acura for instance without some fundamental design changes.

My wife complains that our 2003 Acura feels heavy. It's about 100 lbs lighter than the Prius, shorter, wider, not as tall, very stiff suspension, lower power steering boost, wider 205H55X16 tires. Go drive one if you want to feel what I mean by "tracking". I'm not sure about the caster, which leads to more of a centered tracking feel. I think all of these things make one car feel so much differnt from the other one. Maybe a slightly stiffer suspension (like European version is supposed to have), 16" wheels, less power steering boost might make a difference, I don't know, but I feel it would. People and dealers keep mentioning the power steering being the source of this problem. Maybe Toyota will come up with something there eventually to improve my further. A few magazine testers even mentioned that the PS was over-boosted a little bit.

Toyota is the only entity with the means to take this further now. I could try struts, springs, etc but just don't want to mess up my car and potentially throw away thousands of dollars in search of another 10-25% improvement. If I were a Project Engineer at Toyota, I'd be lobbying to improve the road feel of this car. Just because it's an eco car doesn't mean it has to handle like one. And what about the myth that Americans don't like performance and the Europeans do? Isn't that the ultimate insult! Give me a break Toyota!

Those of you that think the car could be better, please let your service writer know about your concerns. Those of you that think this car is the best tracking car you've owned, go drive an Acura RSX, which by the way is NOT known for it's freeway tracking at all. A long term test of the RSX had the testers saying the car was twitchy and they hated the front end and the way it felt. And yet I'm saying it's a lot better than even my improved Prius.