Rick's Free Auto Repair Advice

Larger tires and plus sizing

Larger tires and plus sizing — pros and cons

Installing larger tires and wheels on your vehicle is the latest craze. They look cool, but if it’s not done properly, you can be setting yourself up for some serious and mighty expensive repairs.

Installing larger tires is called Plus Sizing

For example A “Plus 0” tire is the same diameter as the OE tire but has a larger tread width or larger sidewall ratio. A “Plus One” size is a tire that’s has a 1” larger diameter than the OE tire. Plus Two is a tire that’s has a 2” larger diameter than the OE tires.

tire plus sizing

You can also install a Minus Sizing where the tire diameter is smaller than the OE tire. Minus sizing is sometimes used when installing new wheels and winter tires since the smaller wheels are a little cheaper and the minus sizing results in more sidewall height.

There are pros and cons to larger tires

Pros of plus sizing tires — The advantages of larger tires

• Larger tires and wheels can provide better handling and cornering and the wider tire may, in some cases, provide a larger contact patch, which means more rubber is in contact with the road. That, in theory, provides more stopping power.

• Larger tires may give you more ground clearance, clearly an advantage if you’re off-roading

Cons of plus-sizing tires — The downside of installing larger tires

• Installing larger tires will decrease acceleration and braking and reduce ride quality. The increased tire diameter changed acceleration and braking leverage physics.

• The higher the plus sizing, the worse the ride quality; it’ll feel more like an off-road vehicle. It’ll rattle your brain and knock out your fillings.

• Larger tires and wheels change the suspension geometry for the worse. In many cases, you’ll have to add a lift to your vehicle to accommodate the larger tires and wheels. Adding a lift kit significantly changes the vehicle’s suspension geometry. What does that mean in practical terms?

If you’ve just added a lift kit without also changing the steering knuckle, brakes, axle shafts, wheel bearing size, strut, and stabilizer bar, you can expect

Accelerated wheel bearing wear and failure
Accelerated CV joint wear and failure
Reduced braking

The increased aerodynamic lift reduces all the advantages of the larger rubber contact with the road, leading to reduced stopping ability. Each doubling of vehicle speed increases the required stopping power by a factor of four.

Tire pressure for plus sized tires

When you change to a larger tire, you usually wind up with a tire with a different maximum load rating and that usually means you use a different tire inflation pressure. Use this tire inflation chart to find the recommended pressure for your tires.

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Posted on by Rick Muscoplat


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