Unstable at higher speeds

[GreenRepublican09]

Loving my car so far, but I have noticed that on the freeway the car seems unstable. I feel it being jerked around even in no wind. Anybody know what the cause is? Is the car just really light? Please keep in mind, I'm not going 90mph, just 65-70.

[Devil's Advocate]

Stock tires track "rain" grooves in the road. A lot! Move up to 195's over the stock 185's and there is a big difference.
Otherwise learn to relax and let it go and overall the car tracks pretty straight over the long haul. Its just kind of unusual to let a car float left and right 6" or so as it tracks the grooves.

[dogfriend]

You should have the alignment checked if you haven't done so already. My car felt unstable at highway speeds when I first got it. The toe in was out of spec on the right rear. The car had a tendency to turn one direction a lot easier than the other, giving it an unstable feeling because the correction was not the same in both directions. The worst conditions for feeling this was at highway speeds with a crosswind.

[Boo]

I think the Prius is in fact a little on the heavy side for a car of its length and width.

+1 on dogfriend's suggestion regarding the alignment. The 2nd Generation Prius has a history of being delivered out of alignment. That's why there was a separate TSB about it, and there's a separate, express, 1 year/20,000 mile warranty for it.

In any event, supplementing all of the above suggestions, you might consider getting the BT Tech front Strut Tower Brace and rear Stiffening Plate from the PriusChat Shop. IMO, they improve the car's tracking and handling a lot, especially the Strut Tower Brace.

[Fitzgerald]

Hi, I am also having the same problem.

[EZW1]

ALL of the posts above are sound. These tires track rain grooves like water in a trough. Sanity check the front end alignment. If it's off, it will get corrected. If it's okay, then you purchased some very cost-effectie peace of mind. It's unclear what your mileage is. If your mileage is low and you haven't hit any curbs or potholes then it is probably okay.

[qbee42]

I stayed with the 185 size tires, but swapped out the OEM Goodyear POS tires with some good ones. The difference is like night and day.

Tom

[Mr_Burns]

I have had nearly same problems. My suggestion is to prove the adjustment of stearance and chassis. They has often to much tolerance. After correction of only a little tick in stearance it has a much better handling. May be that better tires also has a positive effect for a better handling. In my opinion the Prius has no good straight running ability. All other cars I owned before has this better done. Sorry english is not my mothertounge.

[archae86]

One other issue is the question of what cars you are comparing it to.

The first car I drove up to 90 miles an hour was my father's 1968 Ford Mustang. I was lucky that I was on a divided highway with no other traffic near me. The thing was wandering back and forth over a substantial fraction of a lane.

Later I owned a 1975 BMW 2002 and a 1987 BMW 325i. When they were new, either one of those cars felt more stable at 90 mph than it did at 50 mph. On the other hand, somewhere up past 100,000 miles on the car I found the 325 felt unstable just doing a freeway past at 85. As people above have suggested, that was my cue for a little suspension work (I forget whether it was alignment or whether I actually needed to replace a part).

So the real question in your case is whether there really is anything specifically wrong with your Prius, or you are just accustomed to cars that track more stably at speed. Perhaps you could exchange cars for a day with another Prius owner who is happy with theirs.

[DaveinOlyWA]

i have had 2 Pri's and never had an issue described here in either one both using stock tires. have the vehicle checked out...

the BT brace helps but not in this situation. i will say, we have bridges here that run east-west across the straits of Puget Sound where the winds funnel between the Olympics and Cascade mountain ranges and on those bridges, the BT brace does help a lot with the north-south winds.