This is for a 2020 T4R Limited with about 600 miles on it so far. Bone stock - no mods. I have never had any other car do this that was maintained properly. I wanted to run this by the group before I take it in for service and ask them about it.

When I drive on Highway 85 between Winchester and Almaden Expressway in South San Jose, the truck oscillates side to side and it wanders like a lost puppy. It is very pronounced and you can't ignore it. I traded in a 2011 Limited that did not do this and I'm a bit puzzled.

My first thought is, it could be the tires interacting with the road. It comes with the mall crawler Geolandar G96B tires and the road has "rain grooves" that run parallel to traffic. My theory is that the tread is squishing around the grooves.

A freeway picture - look at the grooves.
Google Maps

My other thought is that factory caster settings might be weak. The caster is supposed to help keep the wheels straight while driving. So if they didn't get it right from the factory it could wander.

A few questions

1. Is this normal with the mall crawler tires?
2. Has anybody had a similar issue?
3. Do either of my theories hold water?
4. Any other theories?

TIA

It's not the tires. Anytime you have a vehicle that doesn't go in the direction you would like (pulling or wandering), check tire pressure to make sure even and not over/under-inflated, then check the alignment. If caster is low as you think, the alignment will show that. If those things don't work, then start checking suspension.

If it's stock and tire pressures are good and you have no unbalanced load - take it back and let the dealer fix it. With only 600 miles it's their problem. Plus, you want a record of this incase it becomes a persistent issue. If they try to tell you it's normal, remind them your other 4Runner didn't do it. Safety issue as well. Maybe a defective tire.

This^^. I read right past the "600 miles". Dealer visit for sure.

Ok thanks. I wanted to make sure I wasn't crazy. . . Ok maybe a bit, but at least it's not normal.

I had the same issue when my 2017 was brand new and a wheel alignment at the dealership was the cure. Caster wasn't within specs at 2.5 degrees so the dealer brought it up to 3.