You either have a bad tire, a wheel out of balance, or some loose suspension parts. Should have it checked. One other thing would be a bad u-joint in the driveshaft.
The front wheels only
Bad tire, wheel out of balance, bad suspension parts. Have the front end checked.
Looking for a Used Avalanche in your area?
CarGurus has 4,969 nationwide Avalanche listings starting at $2,495.
Search Chevrolet Avalanche Questions
Chevrolet Avalanche Experts