Aftermarket Wheels and Tires on All Vehicles

Installing aftermarket wheels and tires on cars and trucks in the attempt to individualize one’s vehicle with a custom look is very popular. However, installation of these custom wheels and tires presents a number of problems that challenge the performance, handling, and safety of the vehicles. Though it's quite common for people to put oversized custom wheels on their vehicles, changing the diameter of the wheel/tire has a direct effect on the vehicle's emissions.

Example
Dodge Chargers come equipped from the factory with 17 or 18” wheels. It is common for vehicle owners to install 20 or 22” custom wheels and tires to enhance the look and appeal of these vehicles. The problems resulting from these enhancements include:

• Extremely harsh ride due to excessively low profile of tires
• Sluggish acceleration
• Poor handling
• Decreased fuel mileage
• Accelerated wear on all components
• Braking issues due to increased mass (weight of wheels)

The suspension, driveline, and brakes are not designed for the mass and weight of these wheel/tire assemblies. Any change in unsprung weight from design specifications directly affects these conditions. The overall wheel/tire diameters change the way the vehicle tracks and affects wheel alignment. Note: SRT-8 vehicles come with 20” wheels, an upgraded XHD Suspension, and larger 18” brakes with brembo calipers. This scenario applies to all vehicles.

All Wheel Drive Voyager and Grand Voyager

All Wheel Drive Power Transfer Unit Failure
The all wheel drive (AWD) system used on minivans uses a power transfer unit (PTU) that connects the front drive components to the rear drive components. The PTU may fail if identical tires are not used on all four wheels. A difference in tire circumference as small as 0.5 percent is enough to cause a PTU failure.

PTU failures related to mismatched tires are not covered under warranty. Important points to consider:

• Tires should be rotated every 7,500 miles or less to maintain even tread wear
• Correct tire air pressure must be maintained
• When tire replacement is necessary, all four tires must be replaced with a matched (same manufacturer, model, and size) set