I doubt it is the tires. Most likely a poor balance job. When I put tires on my 4Runner, and after 3 tire dealers (one that *claimed* to have the proper adapter) and still having balance issues, I went to the closest Toyota dealer (25 miles) and had them balanced there. That was 60K miles ago and they are still smooth.

Hopefully you have a tire shop (or dealer) near by that has the lug-centric adapter for their balancer so that you can have them properly balanced.

Better yet, a shop that has the Hunter GSP 9700 for the best balance.

http://www.gadgetonline.com/Vibration.htm

hupptoy

99 4Runner SR5 3.4 Auto 4x4, 32" LTX A/T, 154K
93 Toy x-cab 22RE 5-spd 4x4, 31" LTX A/T, 150K