When I got my 40" Iroks mounted and balanced last year, they said they could not get the balance perfect. And I was getting some good vibration around 60MPH. When I put the tires back on this weekend I deceided to try some Dyna Beads. After 45 minutes of pouring them thru my valve stems I took the truck for a ride. Got it up around 75MPH and it was smooth-even after I had lost one of the original weights on one wheel. I must say I am happy with this product!