Red Seal Truck and Transport Mechanic Practice Exam

What is a consequence of using mismatched tire sizes on a truck?

1. Improved fuel efficiency

2. Increased tire lifespan

3. Poor handling and increased tire wear

4. Better traction in wet conditions

The correct answer is: Poor handling and increased tire wear

Using mismatched tire sizes on a truck can lead to poor handling and increased tire wear due to several factors. When tires are not of the same size, they rotate at different speeds. This discrepancy can create an uneven distribution of forces on the axles, leading to instability while driving. It affects steering response and overall handling, making the vehicle harder to control, particularly under various driving conditions. Additionally, the tires that are different in size will experience different rates of wear. The larger tire will have to push through the cornering forces differently than the smaller tire, which can lead to faster wear on one or more tires. This issue not only compromises the vehicle's performance but also increases the risk of blowouts or other tire failures, significantly affecting safety on the road.