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- 2014 CX-5 Touring
I've seen some incorrect information in here about having to use higher tire pressures when tires with a higher load rating than the factory tires are used. This is absolutely incorrect and could lead to premature tire wear and even loss of grip in certain situations.
A tire's maximum load rating is always for 35 psi inflation pressure, for passenger car normal load rated tires, regardless of tire size, brand or construction. This load rating far exceeds the GVWR for the vehicle, which you should never exceed anyway. Additionally, the weight on the tire, and the tire pressure, determine the size (area) of the tire's contact patch on the road. Changing the weight on the tire, or changing the tire pressure, will change the contact patch area. Tire size has no effect on contact patch area. A wider tire will have a wider contact path, but shorter at the same time, so the actual area of rubber will be the same, given the same tire pressure.
Tire pressures can be adjusted temporarily for certain driving or load conditions, but for normal everyday conditions, you should always go by the manufacturer's recommended tire pressure. Doesn't matter if you use tires with a higher load rating, or a higher max inflation rating, or a different size tire altogether. Always use the manufacturer's specs for normal conditions, which is 34 PSI for 17" tires and 36 PSI for 19" tires. Increasing pressure over factory specs makes the tire contact patch smaller (less grip) and will also wear out the center of the tire prematurely. I had it happen to me 20+ years ago before I knew anything about cars. I ran Plus Two size tires 8-10 PSI higher than the factory tire pressure rating, and the center of the tire wore down after just a few thousand miles.
A tire's maximum load rating is always for 35 psi inflation pressure, for passenger car normal load rated tires, regardless of tire size, brand or construction. This load rating far exceeds the GVWR for the vehicle, which you should never exceed anyway. Additionally, the weight on the tire, and the tire pressure, determine the size (area) of the tire's contact patch on the road. Changing the weight on the tire, or changing the tire pressure, will change the contact patch area. Tire size has no effect on contact patch area. A wider tire will have a wider contact path, but shorter at the same time, so the actual area of rubber will be the same, given the same tire pressure.
Tire pressures can be adjusted temporarily for certain driving or load conditions, but for normal everyday conditions, you should always go by the manufacturer's recommended tire pressure. Doesn't matter if you use tires with a higher load rating, or a higher max inflation rating, or a different size tire altogether. Always use the manufacturer's specs for normal conditions, which is 34 PSI for 17" tires and 36 PSI for 19" tires. Increasing pressure over factory specs makes the tire contact patch smaller (less grip) and will also wear out the center of the tire prematurely. I had it happen to me 20+ years ago before I knew anything about cars. I ran Plus Two size tires 8-10 PSI higher than the factory tire pressure rating, and the center of the tire wore down after just a few thousand miles.
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