Tire Flat Spotting
Temporary tire flat spotting is common on New Dealer In-Stock vehicles that have not been occasionally moved. Smooth-rolling tires can be the difference between having a vibration-free driving experience or a shaky one. In order to assure customer satisfaction, it is important to follow vehicle movement procedure to ensure Temporary or Permanent Flat Spotting does not occur after the vehicle has been parked (not moved) for a few days, or longer. In most cases it is temporary. In extreme cases it can be permanent. As instructed in the Assurance Products Resource Manual, vehicles should be moved 12 inches, in one direction only, every 30 days to prevent tire Flat Spotting.
Important Note
New vehicle inventory vibration incidents related to storage Flat Spotting are not considered warrantable repairs.
If tire flat spotting has occurred, it can cause a vibration or shimmy condition that may be noticeable for the first several miles of driving. Tire flat spotting causes the road wheel to hop/bump once per revolution similar to a wheel imbalance condition. Factors that can influence Flat Spotting are:
- Long storage time without moving the vehicle.
- Tire construction (e.g., use of nylon in high performance/high speed tires).
- Short sidewalls on low profile tires (does not absorb bumps as well as higher profile (taller) tires).
- Colder temperatures (makes the tires stiffer). Increases drive time to remove flat spotting, too.
SERVICE VEHICLE TIP
It is important to remove any temporary Flat Spotting prior to performing tire balance, tire run-out, and/or tire road force checks.
- If the flat spotting is not removed it can result in incorrect measurements.
- Temporary flat spots will return to original (near uniform) condition after driving for approximately 15 miles at highway speeds.
Procedure for Eliminating Temporary Flat Spotting
1. Drive the vehicle at highway speeds until the vibration (caused by temporary flat spotting) is eliminated.
Note
- In most cases, flat spot vibrations will be eliminated within 15 minutes (about 15 miles) of driving.
- If the vehicle has been stored without moving for an extended time, it may be necessary to drive the vehicle up to 30 minutes (about 30 miles) at highway speeds.
- If the vibration goes away during the test drive, no further action is required.
- If the vibration is not completely eliminated during the test drive go to step 2.
2. Within 10 minutes after driving the vehicle, lift the vehicle so there is no load on the tires.
3. Check the tire/wheel assemblies for balance, run-out, and road force variation. Correct as necessary.
