sway bar(s) for prius

I might be in the minority by saying this, but I'm not at all interested in sway bars or anything that makes the Prius ride any firmer than it already does.

I'm not going to turn the car into a Rice Rocket or become a Boy Racer. Nor am I going to go blasting around mountain curves at illegal speeds.

I just want the car to track with confidence when I have the cruise set at 100 km/h on the Trans Canada. Lately I've been setting the cruise at 90 km/h just so I don't have to worry so much.

As Fred mentioned, some cars truly do track like on rails. My parents 2003 Buick LeSabre is one such car, and their close friends have a 2003 Lincoln Town Car

An odd thing about tires: in winter I run Dunlop Graspic DS-2 studless winter tires on their own steel rims. For some reason, the car seems to be *much* better behaved at Trans Canada speeds.

That really shouldn't be the case. The Graspic DS-2 has a heavily siped tread, chunky tread pattern, very soft and squishy tread itself, and a huge amount of sidewall flex. The ride is much softer and tolerable over potholes and frost-heaved expansion joints.

As far as ride quality, I've driven a few times down to the Twin Cities and further to Rochester when my parents have had doctor appointments at Mayo. We went once and only once in my Prius.

Once you get to the typical smooth highways south of Canada, the Prius is like any other car. Tracking issues aside.

And I don't think I'm inducing any motion. I've tried letting go of the wheel when the Prius gets a mind of its own, and then it become much worse and SCARY.

If you have to deal with potholes and severely buckled pavement and expansion joints caused by frost heaves, the ride is bone jarring. It quickly becomes tiring and annoying.

If you really want a thrill, drive the Prius on a severely washboarded gravel sideroad. Like I do when I drive the 5km gravel sideroad to my hobby farm. If I had to regularly drive down such roads in a Prius, I wouldn't. I'd find a different car and pay the extra in fuel.

What I really don't understand is that I've gone for a ride a few times in a coworker's new Chevy Aveo. That cheap little thing has a very soft and compliant ride, though you can tell it's cheaply put together - still better than a Cavalier - and unimpressive otherwise.

At Trans Canada speeds that little Aveo also appears to be fairly stable, at least more so than the Prius. What irks me is that the tracking/stability issue isn't predictable. So who knows what it really is?

 

<div class='quotetop'>QUOTE(jayman\";p=\"103908)</div>

Hi Jayman,

I think that you are actually in the majority, not the minority. Most people will not modify their Prius, just like most people don't modify whatever else they drive.

Getting a firmer ride is definitely not my goal either. The Prius rides firmly enough and I don't want something that rides like a sports car (I've owned plenty of them and the Prius rides softly compared to any of them).

What I would like is a resolution to the less than spectaculr handling and excessive sway. In my case the car actually does well most of the time so I feel it only needs a small amount of help to satisfy me.

For everyone else that has severe problems with handling and excessive sway (not the same thing as there have been cars with great handling that had quite a bit of sway), and have gone the full route of having the dealer check out the alignment and everything else they could possible check out then another possible solution would be to befriend a reputable local racing mechanic.

Have them drive the car where its most likely to act up and hopefully they will experience the problem. Their input could prove interesting in identifying the problem (it could be quite different from what we have been trying to guess). It would be much more helpful if we could find a racer that has expertise in Japanese brands, as they may have their own unique issues.

By the way, I am not offering polyurethane sway bar bushings as a universal panacea, its just what I am planning on doing to my car. I am not sensitive to any increase in ride harshness due to poly bushings (I just don't feel it). The true issue, if there is one, is that I have not researched is the Prius has a rear sway bar. If it does then swapping to poly bushings will hopefully offer a big improvement. If it does not have a rear bar, I will probably not do the mod as it could result in excessive oversteer, certainly an undesireable condition for most of us (except those 911 drivers that like oversteer ).

Searching the Internet to see if anyone has figured out what the handling issue is all about I stumbled upon an interesting line:

"The Prius isn't the kind of car you buy for handling. The handling is adequate, and is comparable to other "soft-riders" in this price range. But it's not the kind of car with which you go zooming around corners. Besides, if you drive it like a sports car, you're going to defeat the purpose of buying it—to save fuel and reduce pollution."
http://www.cartalk.com/content/testdrives/...prius-2004.html

"Soft-riders"? And they didn't mentioned the sway or squirminess? I guess its all relative.

 

It looks like the "better handling" Prius is for the UK not the US. They already have larger tires and helper springs for better handling so that's not saying much for the US version is it? I know that I did talk to owners over there that had the same complaint about wandering.

If only Toyota would have the sense to offer some of this to the US...like a GT kit or something. If the PS is a problem I can't believe they could not offer a relatively cheap fix for us. I'm not expecting sports car handling, just something that feels predictable and safer. I'd gladly pay $1K or more to improve this car. As for the dash squeaks etc...I'm heading back to the dealer next week to get them to make another attempt at fixing my car. I've never spent more time at the dealer with any car I've owned.

OK, so how do you get Toyota Japan to talk to you Gen2??? I can't even get the US rep to meet me face to face...he just pronounced my car like all others to the dealer and was gone before I knew it. And I insisted on seeing him but that didn't stop him from ducking out.

 

Oh I posted some pics of my dealer's putty fix here:

http://priuschat.com/forums/viewtopic.php?...p=103988#103988

 

I think we're all just looking for (and trying to say) is to have a NA Prius that handled with the predictablity and assurance of a stock Corolla/Camry; which the Prius currently underperforms.

It's very much "Toyota! Get your Corolla suspension engineering teams on the Prius now! The Prius team does well on the propulsion, but keep them away from the handling".

 

<div class='quotetop'>QUOTE(NuShrike\";p=\"104114)</div>

Well said!

 

IT's THE TIRES !!!!
I now have 4,500 miles on my Bridgestone RE950 185-65/15 tires and my Prius now handles like a go kart. However, above 36/34 psi the ride becomes very firm to harsh on irregular roads. The Prius suspension (springs-shocks) is very stiff and it shows when you have a sport tire attached. When I do a highway lane change there is now almost zero lag with the back end of the car "chasing" the front. The turn-in is average to good (as good as you get with 65 series tires). I have just a little tire roll on turn-in with minimum body roll (total lag is less then one second). I am seeing a 2-4 mpg drop with the Bridgestones (their wet traction is unbelievable also).
The stock Integrity tires are like riding on the edge of a thin piece of plywood. They are very stiff when rolling in straight line, but subject them to a side load and they bend like a politician before elections.
I've even asked Eibach if they wanted to make springs that were 15-20% LESS stiffer then the stock springs(no response). Changing springs would be easier then trying to design a "sport" tire for a highly sprung-light car. I think Toyota picked the Intgrity tires and then tried to compensate with stiff springs-shocks.
I'll have full report on the RE950 tires in about a week.
Move your air dams forward, it helps on the highway.

 

<div class='quotetop'>QUOTE(200Volts\";p=\"104207)</div>

Thanks for the report 200. I am so glad that you found a solution that works for you. I read several posts here where owners have changed the tires but have not gotten any relief. Glad to hear that it worked for someone.

 

<div class='quotetop'>QUOTE(200Volts\";p=\"104207)</div>

If it's the tires then it's also the Michelin Hydroedge tires. I'm one of those that don't think my tire change made any difference. And I tried the 195HR60X15 size for a month as well. The Austrailian Prius gets that size in another Michelin model and I've heard the same ill handling reports from there as well as countries in Europe where they have the 195 size and 16" wheels. But I have no doubt that a true high performance tire can help. I don't think I saw more than a 1-2 mpg change with either size if that.

So if the springs are stiff on our cars, then the European version must be terrible with the extra (stiffer) helper springs right? Is it the springs that are stiff or the damping? The car seems to sway very redily from side to side "as if" the springs initally were too soft. Or is this just the result of weak anti-sway bars? This rocking seems to contribute to the wandering or is it the wanders causing the rocking. At any rate for those of you that would like to try stiffer springs I offer this link to what Nascar and many sports car owners do. It does appear to raise the car if you're not careful and it seems like it might reduce the overall travel, which doesn't sound like a good thing to do. I remain, as every, very confused and disappointed about how and why my car does what it does on the freeway.


http://home.the-wire.com/~pg/928/Tips/spri...ing_wedges.html

 

Wimpy Tire Test.
Park your Prius on a flat surface.
1-Go to the back bumper, on one side or the other. Push horizontally on the side of the back bumper and you'll see the front of the car move left to right. While doing this now look at spacing from the rear WHEEL (not the tire) to the fender. You'll see this distance-orientation shows very little change. Hence the tires are flexing in this yaw axis.
2- Now go to the driver's door and push on the "B" pillar at the roof line (the "B" pillar is at the rear of the front door). You will be rocking the car from side to side. Look again at spacing from the front WHEEL(not the tire) to the fender. You'll see this distance-orientation shows very little change. Hence the tires are flexing in this roll axis.
IF the springs were mushy you would see this wheel-fender distance changing. It takes very little pressure to do this. MUCH less pressure then is exerted by a cross wind at highway speeds.
You can also sit or load the front fender or back cargo area with 225 pounds and see little change in ride height(especially on the front). Thus the springs are not the weakest link.
With my RE950 tires test 1 and 2 hardly move the car at all.

 

<div class='quotetop'>QUOTE(200Volts\";p=\"105056)</div>

Sounds like a great test, thanks. What about all the talk about the vagueness of the electronic PS. Virtually every road test says things like vague, inaccurate, numb, disconnected, no feedback, etc. And now we've heard a rumor that Europe is getting a bunch of changes to their new Prius that includes "recalibrated" PS, stiffer chassis, improved suspension, etc. I'm hoping some of this filters down to us in the US if there is some way to improve the steering feeling and hence the feedback to the driver.

I'm just not entirely conviced it's all tires, but I have to admit that on my RX-7, going from Yokohamas to Bridgestone cured an even more pronounced freeway wiggle in road grooves. I was ready to sell that car until I switched tires and I think they were 950's or 750 Bridgestones too. Wish I had kept the receipt.

 

200 volts....another question for you. Did you consider the larger 195HR60X15 size? How long have you had these tires? If they're pretty new then the gas mileage might increase some after 1000 miles or so. I could not tell much difference with my mpg with the Hydroedge. Even the larger size yield almost exactly the same gas mileage on a round trip to Vegas. I kept the larger size for about 1000 miles and only thing I felt was that around town it "seemed" more difficult to get those high mpg extended trips. But the overall data said the mpg's were virtually identical. I've track my gas mileage from day one and there's just no difference with new tires or larger size that I could see.

What kind of mpg's are you getting now with the new tires? I can barely muster 48.5 overall for 15,000 miles. For the warmer weather it's 49-50 with 35/33 pressure and maybe 50-52 with 42/40 from what I can tell. I sure would not want to loose 4 mpg. But those 950's look very similar to the 750's that I think I used. Since the 750's don't support our sizes the 950 is a very logical choice. Keep up the good work and give us an update on your progress...thanks.

 

I chose the stock tire size for a direct size comparison (sale price $70 each w/mounting,balancing,etc.). Plus I was guessing the lower 60 profile would be an even rougher ride. I will publish a full report that shows at 36/34 psi the 950 tires are slightly under inflated (less wear in the center of the tire on all four, versus inside and outside of the tires). My stock tires at 38/36 lasted to 40k miles with almost perfectly even wear (outside of tire on driver side wore most). Maybe tehe 60 series tire would wear better at the same pressure(?).
The national sales manager at Bridgetone reccomended the 950 tires to me. I have 4,500 miles on them. I was getting 51.2 mpg with the stock Integrity tires and now I get about 48.5 (range has been 44 to 55 mpg).
The 950 tires have unbeleivable traction and I think they heat up more on the highway (they go up about 5psi in pressure). This is from 36/34 psi cold (which feels about like 40/38 psi with the Integrity tires).
When I ran the 950 tires at 40/38 I only saw a drop of 1-2 mpg, but the ride was extra firm.
My first choice was the Bridgstone G009 due to higher wear rating(harder compound?) and better snow traction. The G009 is a much stronger directional design then the 950.
I hate the electronic PS the way it is set up. I drove a Ford Probe for 2 days last month and it's steering is perfect (especially the narrow spoked steering wheel). The Probe has no center play at all and a perfect amount of feedback and resistance(effort).
I also drove a rental 2005 Prius for 2 days and it felt tighter then my 2004 with 40k miles, but not a huge difference. I think that TRW has a patent on electrically assisted power steering (I don't know who makes the Prius ps).

 

The hydroedge tires are also stiffer than the stockers, at least they feel that way especially at higher pressures. I did think the wider size tracked better but chose the std size because at that time I had some hope in getting Toyota to help me. My thinking was with the std size the could not blame it on the tires. I later found that they used the larger size on the Australian version, 195HR50X15 so I'm thinking of getting another set of tires even though these have only about 7K on them.

So most of your miles are with the colder weather then right? Maybe that's the reason the mpg is down some? Even here in SoCal my "winter" mpg was in the 44-46 range and summer or spring about 49-52. I'm just trying to determine how "bad" the 950 is. I've also considered the Goodyear triple tred because of the lack of circumfrential groove, thinking that might improve handling in the road grooves here. Any thoughts?

 

I drive in the Stockton - Livermore area the most and it's been in the 90 degree+ range for the last 6 weeks. I drive almost 1,000 miles/week so this is not cold weather results.
Even with 4,500 miles on the 950s the mpg is just a guess, since this is only 9 tanks of gas. It's been windy(5-15 mph average speeds), I've had runs of 80mph (usually I try to drive highways at 75mph) and rush hour traffic varies. Going around corners now is accually fun so this will effect mileage as well.

 

I currently have Michelin Harmony on and although they helped a bit on the highway, it was nothing spectacular.

Thanks for the advice.

 

<div class='quotetop'>QUOTE(200Volts\";p=\"105466)</div>

Yes, even with the Hydroedge I go much deeper into a corner and often don't hit the brakes. It can help avoid the momentum losses but the temptation is to gas it a bit in the corners. The wider size was much better for this though. Maybe with the 950's and some of those suspension components I've seen from Japan (Carson Site, etc) we might have our own version of the Prius GT! I don't really need the extra hp to make driving the Prius a bit more enjoyable.