4Runner sensitivity to front wheel balance is a well known issue.

When you get your wheels Roadforce balanced you have to be specific on what you want to get the best results. Ask the tech what the Roadforce numbers are for each wheel - these basically tell you how out of round the tire is. From my experience, under 10 is good, 10-20 is acceptable, over 20 is bad. The larger and/or more aggressive the tire is, the more likely the tires are to be out of round and have worse Roadforce numbers. Once you have the Roadforce numbers, tell the tech to put the lowest on the front and highest on the rear.

I started doing this years ago and it greatly reduced the 55-65 steering wheel shimmy. I still get it on cold mornings when the truck has been sitting - it usually goes away once the tires warm up.