Question about front & rear sway bar changes.

If the rear of the car really is wiggling around, I would think that you would need to make frequent steering corrections to keep the car going straight down the road. Do you find that to be the case? If so, there may be a real problem with the car's suspension that hasn't yet been identified.

 

Hmm, if the problem is really only one of your own perception of the car not being stable, I'm not sure sway bar changes would help, although I'm not qualified to offer a professional mechanic's opinion. I guess if you could convince yourself it was better (placebo effect), they would help.

 

Strange that you mention the rear end moving around and feeling more bumpiness coming from the rear, I have that same feeling when driving the GFs Honda Civic, it never use to do that even after putting on new struts and shocks all around, then a couple of years ago things changed one day and now it feels like the rear wants to hop around on its own.

Back to Prius : I notice a steering wandering issue at freeway speeds quite often, and will look around at the flora and fauna for potential wind which might be causing such.. then realize there is little wind.

The gen2 is notorious for wandering, or so I believe. One of these days (hopefully not soon) I will ask an officer what they think.

Right after purchasing this Prius I installed a used solid core rear sway bar ($25) hoping it would make a difference in the wandering, it may have, though I'm not really sure. I still think installing a front solid core bar could help ( @DivideByZer0 are you out there ).

Solid core sway bars (Toyota or aftermarket) may or not make a noticeable difference to you, but moving up to a wider/lower profile tire possibly could if you're currently rolling on the 185/65/15's.

I recently downgraded from a 'Touring' tire/wheel size of 195/55/16 to the 'Non Touring' base tire/wheel size of 185/65/15.. and made a big mistake in going with narrower/taller tires (like all the other gen2). If I could do it over, I would've put 195/60/15 or 205/60/15, if not a 215/55/15 on all four corners (or insert any shorter/wider tire that a tire shop will mount, call around first as not all will)

Now this Prius wanders around even more than I remember, of course I'm still hoping its just the new tread depth (12/32) wiggling around on these grooved roads. Don't know if my excessive wandering was from going narrower, taller, or both

Now I have a front strut tower brace that I've been meaning to install, and if that fixes my "faux drunk driving" I will be impressed. Otherwise I am stuck with these "new tires" until I replace them with something shorter/wider.

Remember not all aftermarket sway bars are solid core, do the math before committing.

Somewhere on here I read about replacing worn out 'end links', 'tie rods', or "something else on the front end" which made the gen2 handle 'like new' again. Seemed fairly convincing, but can't find that post via search

Here is a link to help with tire sizing : Rim & Tire Size Calculator. Custom Offsets - Wheel-Size.com

 

there are undercarriage braces from japan that should tie the car together better; justdidit had some for sale after his got totaled. the sway bar upgrade reduces body roll, but that might not help with motion sickness. it likely does stiffen up the rear axle beam, because the rear bar bolts inside of it, and that might help some. I would go ahead and get the rear bar and try it out. very easy install. you should also get trd or some type of better hardware with heavy washers too; the oem bolts are really too small. someone took a picture of the trd bolts and the heads and nuts were definitely larger. I used Benz S500 control arm bolts, but you have to cut them shorter.

 

$#!+ happens. the braces are only sold in japan as near as I can tell. somewhere you might find a link to the site, but unless you can read Japanese, gonna be difficult to figure it out. search justdidit's posts. there should be a link in his thread; also there was a guy in hong kong with a heavily modded gen 2.

 

Sigma Automotive will import you all the chassis braces you want, and their site is in English!

 

You want the front upper strut bar, the body stiffeners and a thicker rear lower bar.

Clear your history and try searching again.

 

It may be very well the case that a stiffer rear sway is detrimental for the Prius. The sway bar ties up the opposite wheels to prevent the car from 'swaying' around the corner.

However, with the Prius uber soft spring rate, when with side of the wheel experiences a bump or a jolt, the stiffer sway bar easily communicates it to the opposite wheel.

I was also thinking of wider tire tramlining the road but even plus size wheels on a Prius isn't wide enough to experience tramlining.

 

nope. thicker rear bar works great. you haven't tried it or you'd be wishing you installed it the day you brought the car home. But, if you drive aggressively, it will oversteer unless you add the front too. the front corolla/matrix bar balanced it out nicely; with just the rear it felt like it wanted to fishtail if I took a corner too fast. body roll definitely reduced even with just the rear bar.

 

What tires do you currently have on the car and what pressures front and rear?

Completely different car, but I had some problems on my Porsche with with oversteer due to having different tires on the front and rear from the previous owner. Running 5 psi more on the rear tires corrected the problem and the car is now slightly understeery, which is perfect for street use. You might try running 5 psi more on the rears than the fronts and see how the car feels (like 35 front, 40 rear). Increasing rear tire pressure reduces the tendency of a car to oversteer.

Also the bushings on older cars can get soft/spongy/worn, which can allow wheels to toe out slightly under cornering/movement which gives an uncontrolled kind of feel. If you have it from the alignment shop, I'd check what toe settings they have on the car versus factory spec'd. On most cars it's with a slight toe in front and rear for stability. To get the same stability feel on an older car, even more toe in is needed due to the worn bushings.

Also, some people on these forums swear by a front strut tower brace for stability.