Originally Posted by 02SE

It's been going on since Toyota switched to steering racks on their trucks and SUVs. So '95 with the introduction of the Tacoma, then the 4Runner in '96.

Steering racks are more sensitive to any tire uniformity or wheel run-out issue. Trucks and SUVs have bigger, heavier tires than cars, so any tire uniformity or wheel run-out issue is more likely to be felt.

The upside to using steering racks is that the steering is more precise than the old recirculating ball systems.

So it generally IS a tire or wheel issue. Of course if we're talking an old vehicle with worn chassis components (ball joints, tie-rods, etc.) that can contribute to uniformity/run-out issues being more readily felt.

Some tire manufacturers just do a better job building round tires. I avoid the ones that have a hard time doing that. Having a competent tech installing and balancing the tires also helps.