well, only at about 50 and up. The Vibration is rythmatic in that it gets really rough for a few seconds then it gets pretty smooth. Almost exactly on tine everytime. This happened when I put the 38's on my truck. Bent wheel? Balance the tires? They are swampers TSLs and I know the should vibrate but this makes my steering wheel move an inch or two when it gets going. ANd I dont notice it around town. Or I dont think I do. Let me know if you have experienced this before or any ideas. Otherwise I will just go have it balanced tomorrow