Instability on highway

No, not at all.

 

More than likely it's the tires, first time I got the 2014 Prius I felt like I was wandering around the road on the rain grooves. My Tundra never has done that, though I've felt that sensation on the Harley on some highways. That's not a good feeling.

Anyway my Prime is much better IMO than the old car, in all honesty I just got used to it. I'm pretty sure the LDA had nothing to do with it. Personally I did lower the sensitivity of the LDA, but that's another story.

 

When I got my car from the dealer, the tire were at 50psi.

You might want to check yours.

jp

 

haven't noticed anything either, have taken mine up to 105 and was surprised how well it did ... I have the Toyos set at 42/41.
I took the 91 west going from Temecula to LAX when I had the car for a week or 2, again, didn't notice anything unusual

 

May just be the tires, but it is possible for the alignment to get knocked out of spec during shipping. It could also be in spec, but with less toe in than you are use too. That increases cruising efficiency, but can increase wandering, squirrelliness, etc. while going straight at speed. The road grooves just exacerbate whatever it is.

 

Tramlining - Wikipedia ??
Groove wander - Wikipedia ?

 

On my Prius Prime Plus, there is too much negative camber on the rear wheels and the passenger front. In theory, negative camber helps on taking curves BUT I suspect it can also couple with the road to induce a side-to-side 'hunting.' Unfortunately, Toyota won't help in correcting the negative camber.

Bob Wilson

 

I have noticed it also. I am thinking it is the alignment as was noted above.

Anyone gotten Toyota to do an alignment under warranty?

 

That is the likely cause, but the degree can vary upon tires, alignment, and car model.
IIRC, our gen2 was worse than other cars on the same road.

I say have the dealer check the alignment after checking the tire pressure.

 

When you go to the dealer, say something like:

"I was driving the other night when I hit a massive <pot hole | tree limb | truck tire tread> and ever since, the car has been squirrelly trying to drift off to the road. Please check the alignment and give me a copy of the result. If the printer is down, I'll be happy to take a photo with my cell phone. I need to show it to my <wife | husband | Dad>"​

Bob Wilson

​

 

Yes but it isn't easy. I'm using shim tabs on the rear and will be adjusting the front camber bolt next. Worse comes to worse, I can replace the camber bolt with one that allows a greater range.

Bob Wilson

 

Have you adjusted the toe already? What is the recommended settings for our cars?

 

No such wandering problem with our Toyo tires. Do check your cold inflation pressure. The sticker on the door jam has the correct pressures (do I remember right...36 front & 35 rear?) Some tires on some pavement will just follow the grooves--can't be helped.

If the alignment was off from delivery, then it is a pre-delivery set up problem. That should be the dealership's responsibility. If I told the shop that I hit a pot hole or something and knocked the alignment out, then it would be my responsibility. The only time I think alignment would be a warranty claim would be if suspension parts were replaced under warranty where the replacement work changed the alignment adjusters.

 

This happens in my gen 2 Prius, especially, but in the gen 4, the Toyos are very unstable IMO. Maybe you aren't used to the thin tires of the Prime compared to your old car. My gen 4 pulls left and right more often in construction zones and on the 405 around Irvine.

 

We owned a 2003 Prius between 2005-2016. During that time, I eventually solved the neutral stability that cause the car to not tract a true line. I solved the problem by replacing the front tires with over-sized tires, fires to correct the speedometer/tripmeter error and later as a type of poor-man overdrive. Larger diameter and heavier tires, they also increased the wheel gyroscopic stability. The effect was quite dramatic when I first stumbled across it.

I drove up to Hybridfest one year with a pair of 'true sized' tires on the rear and the a pair of recommended front tires. The car handled like when I first got it, drive it every second and no distractions. At Hybridfest Sunday morning, I swapped the front and back and the handling definitely improved:

This is a photo before I started my poor-man overdrive test, the tire in the middle. Notice the front tire is larger than the rear and this was the first change that improved stability. It also brought the speedometer and tripmeters into true values.

Bob Wilson