2021 Hyundai Wheel/Tire Vibration TSB 20-SS-004H

Hyundai has released Technical Service Bulletin (TSB) 20-SS-004H to address concerns related to wheel and tire vibration in all applicable Hyundai models, including the 2021 Hyundai Elantra. This bulletin outlines comprehensive service procedures for diagnosing and resolving vibration issues, focusing on wheel/tire balance and Radial Force Variation (RFV). TSB 20-SS-004H supersedes the previous TSB 15-SS-002, introducing updated procedures and a new "Tire Balance Data Sheet" for more accurate diagnosis and repair.

This TSB is crucial for ensuring optimal vehicle performance and passenger comfort by effectively managing Hyundai wheel tire vibration concerns.

Symptoms of Wheel/Tire Vibration

Owners may experience noticeable vibration while driving, which can vary depending on speed, road conditions, and ambient temperature. A common symptom is vibration that occurs during the first few minutes of driving but then diminishes. This is often due to temporary tire flat spotting, which can happen when a vehicle is parked for extended periods. The TSB emphasizes accurately identifying and recording these customer concerns, noting conditions like speed ranges, ambient air temperature, road conditions, and whether the vibration occurs within the first 10 minutes of driving.

Important Warnings and Owner Information

Hyundai provides critical guidance for technicians and owners regarding wheel and tire vibration diagnosis and repair:

• Data Sheet Requirement: For all wheel/tire balance and RFV vibration claims, a detailed “Tire Balance Data Sheet” must be fully completed and attached to the repair order documentation. This sheet captures initial and final measurements, customer complaints, and environmental factors.
• Tire Pressure: Air pressure must be set to the vehicle's placard specification (cold) BEFORE performing any service procedures. Environmental factors like colder ambient air or higher elevation can reduce tire pressure, while hotter ambient air can increase it.
• Warm Tires for RFV: All Radial Force Variation (RFV) measurements MUST be taken with warm tires. If measurements cannot be taken immediately after a warm-up drive, the vehicle should be lifted on a hoist to remove weight from the tires. This helps prevent temporary flat spots from developing and ensures accurate readings.
• Balancer Calibration: Periodic calibration of wheel balancing equipment is essential for accurate measurements. The latest calibration date is required on the Tire Balance Data Sheet. If calibration has not been performed within the past six months, contact your local Hunter representative to schedule calibration.
• Do Not Replace Prematurely: If the vibration complaint is not resolved after following the outlined procedures, contact the Hyundai Technical Assistance line at 800.325.6604 prior to replacing a wheel or tire. It may be necessary to investigate other sources of vibration before replacing components.

Diagnosis and Repair Procedure for Hyundai Wheel Tire Vibration

The service procedure for addressing Hyundai wheel tire vibration involves several key steps to accurately diagnose and correct the issue:

1. Initial Inspection: Technicians begin by thoroughly inspecting the wheel and tire assemblies for any visible damage. This includes checking for bent rims, missing balance weights, irregular tire wear patterns, or any debris lodged in the wheels. All findings are recorded on the Tire Balance Data Sheet.
2. Tire Pressure Adjustment: The "as-received" tire pressure is recorded, and then the cold tire pressure is adjusted to the specifications found on the vehicle's placard.
3. Test Drive and Confirmation: The vehicle is test-driven for at least 20 minutes at freeway speeds. This warms the tires and helps minimize the effects of temporary flat spotting. If the customer's vibration complaint is confirmed during this drive, the wheel and tire assemblies' balance and RFV are measured and recorded.
4. Initial Measurements: Immediately following the warm-up drive, the vehicle is lifted off the tires on a hoist. The tires' initial positions (front left, front right, rear left, rear right) are marked with chalk. The wheel/tire assemblies are then removed to check their balance and RFV, with all initial data recorded on the data sheet. The lug nuts are torqued to 65.1-79.6 lb-ft (9.0-11.0 kgf.m or 88.3-107.9 N.m) during reinstallation.
5. RFV Guidelines: The TSB provides guidelines for acceptable RFV values:
   • P-metric passenger vehicle wheel and tire assemblies: 18 lbs or less
   • P-metric SUV and van wheel and tire assemblies: 24 lbs or less It's important to note that these values are a guide, and it's possible for a vehicle to have RFV values greater than these numbers without experiencing a vibration issue.
6. Rebalance or Force-Matching:
   • If RFV values are within guidelines but imbalance issues are present, the assemblies are rebalanced as necessary, followed by another test drive to confirm the repair.
   • If RFV values exceed the guidelines, or if vibration persists, a force-matching procedure may be required.

Force-Matching and Tire Placement

Force-matching is a specialized procedure designed to minimize RFV values by aligning the tire's high point (stiffest spot) with the wheel's low point.

1. Preparation: All existing balance weights are removed from the wheel. The wheel/tire assembly is mounted on a balancing machine (such as a Hunter GSP9700), and the balance and RFV measuring procedure is initiated. The high point on the inside of the tire, as indicated by the machine, is marked.
2. Rim Runout Measurement: Rim runout is measured according to the wheel balancer's instructions, and the low point on the inside of the wheel is marked. For some wheels without an outside lip, the rim runout may need to be measured on a bare rim (without the tire).
3. Alignment and Re-inflation: The assembly is moved to a tire changing machine. The bead is broken, and the marks on the tire and wheel are aligned. The bead is then re-seated, and the tire is inflated to specification. The RFV value should be confirmed as reduced on the wheel balancer, and the final RFV values are recorded on the data sheet.

To further reduce vibration, the TSB specifies how to arrange the wheel/tire assemblies on the vehicle:

• Non-staggered tire sizes: Front Left (Lowest RFV), Front Right (2nd lowest RFV), Rear Left (3rd lowest RFV), Rear Right (Highest RFV).
• Staggered tire sizes: Front Left (Lower RFV of front tires), Front Right (Higher RFV of front tires), Rear Left (Lower RFV of rear tires), Rear Right (Higher RFV of rear tires).

Hunter GSP9700 Wheel Balancer Best Practices

For reliable and accurate measurements, proper mounting of the wheel on the balancing machine is critical. Technicians should:

• Select the correctly sized cone for the wheel hub bore, typically 65-70mm for most Hyundai applications. The cone surface should be inspected for damage and replaced if necessary.
• Ensure the wheel hub sits as close to the middle of the cone's tapered surface as possible, engaging the wheel bore near the middle of its engagement depth.
• Perform a "Centering Check" on the balancer. A green screen indicates proper centering, while a red screen means the assembly is not properly centered, and balance/RFV results will not be accurate, requiring re-centering or a different mounting method.

Warranty Information

This service is covered under normal warranty provisions.

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Source: NHTSA ID: 10186716, TSB 20-SS-004H