Twitchy handling Sedan / carsick kids, headaches

[theraymondguy]

2007 Sedan, auto with power group. Factory 15" alloys, stock tire size and recommended inflation. Generally it has no weight in trunk and is driver only occupancy. Car is box stock with the exception of synthetic engine oil.

It has been an overall fantastic car. We're the second owner, have had it for 2 years.

The car is not driven in a spirited fashion, though I'd like to use it for our "Florida Vacation road trip car" which has 2 opportunities:

My daughters (9 and 12) complain of headaches when road tripping, though no complaints when travelling in our '05 Kia Sportage. The Sportage has rear tint, I'm thinking this may be all that is needed, but was wondering if others had the same issue.

I've noted the car feels twitchy at highway speeds when road tripping, like it could change lanes merely at the suggestion. Playing with tire pressure hasn't had much effect, tires are Hercules brand non-directional. Rear suspension feels soft (has always felt soft), perhaps more so as our girls grow.

With a modest budget, what would be the most likely fix? Swaybar? I could swing a tire swap (Always happy to install Michelins)? I don't want to get heavy into suspension mods or lowering (My wife likes the stock ride height).

Thanks for input!

[tmontague]

I'd recommend a simple tire swap, go with a directional tire and fill the tires up above the factory recommendation. No need to go crazy spending money on suspension.

I would however inspect your suspension, the oem struts/shocks last a long time (~180k km) but if they are worn your car will be less stable

[kimona]

On the highway, my 2007 behaved as you describe. I installed a TRD rear anti-sway bar, which certainly improved handling, and provided some sense of stability at speed, but didn't eliminate highway wander. Actually, the car was a bit scary to drive on the highway.

After experimenting with numerous tyres, I discovered that tread pattern makes all the difference in highway behaviour. I've been running tyres with a non-aggressive tread pattern and a wide continuous centre band. Without the antisway bar, I completly eliminated "twitchy handling" and highway wander.

[theraymondguy]

Thanks guys!

Tmontague, It's just rolled over 175k KM, so I'll definitely have a look at the suspension. I replaced the stabilizer links last year and didn't notice anything then, but I'll have another look to be sure.

Kimona, if I'm on the same page, you mean a tire similar to this, with a substantial center band?
https://m.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=Advantage+T%2FA+Sport+(T-Speed+Rated)&partnum=86TR5ATAS&vehicleSearch=true&fromCompare1=yes&autoMake=Toyota&autoYear=2007&autoModel=Yaris+Sedan&autoModClar=&autoMake=Toyota&autoYear=2007&autoModel=Yaris+Sedan&autoModClar=

[kimona]

1. This was the first tread pattern that worked very well for me on my 2007. I ran 2 sets of these Zeetex tyres.

2. This Kumho was also excellent on my 2007. Now, I'm running a set on my 2014.

[malibuguy]

Toe out will cause the car to dart and tramline on crappy pavement. Toe out is desirable on performance alignments as it helps with ackerman typically and results in more mid corner grip. I run a bit of toe out on mine...with summer tires its ok...when I put the 225 hoosiers on its almost uncontrollable.

It sounds to me your alignment might be suffering from a bit of toe out...due to possibly worn out control arm bushings, tie rods or even worn ball joints.

And as said higher quality tires and maybe slightly increased tire pressures could help.. Our cars are spec'd at 29psi. I used to run over 50psi when I cared about gas mileage. However these days I typically run 34f/31r cold.

[kimona]

^^^ Interesting. When I ran higher tyre pressure, my little car bounced all over the place like a basketball.

[malibuguy]

^^^ Interesting. When I ran higher tyre pressure, my little car bounced all over the place like a basketball.

I was up to 56psi at one point. In my old xB i ran 64psi for a while.

When you commute 110miles a day like I used to You try to find a way to stretch out them fill ups.:bonk: