It's very likely that an out-of-balance tire will shake only at certain road speeds or only above a certain road speed. Is it totally engine speed dependent or road speed dependent?BuRn__ said:ive had car tires that were out of balance, and it caused a shake at any speed, just varied depending on the speed. this only happens at a certain rpm range.
If road speed, suspect the tire balance. If really engine speed, it may be engine vibration induced. The front forks may somehow have a natural frequency related to engine vibration at certain rpms. Might also want to check that all front end bolts are tight.