235 55 r 18意思
"235 55 R 18" is a tire size designation, specifically a tire profile for passenger cars. Here's what each part of the designation means:
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235: This is the tire's section width, which is the width of the tire in millimeters from one sidewall to the other when it's mounted and inflated on a rim. In this case, the tire is 235 millimeters wide.
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55: This is the aspect ratio, which is the ratio of the tire's sidewall height to its section width. The sidewall height is 55% of 235 millimeters. So, 55% of 235mm is 129.75mm. This means the tire has a relatively low profile, which affects the ride comfort and handling characteristics.
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R: This letter stands for "radial," indicating that the tire is constructed with radial ply, which is the most common type of tire construction. In radial tires, the ply cords extend radially across the tire from bead to bead at a 90-degree angle to the direction of travel.
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18: This is the wheel diameter, which is the size of the wheel in inches that the tire is designed to fit. In this case, the tire is designed to fit on a 18-inch wheel.
So, a tire size of 235/55 R 18 indicates a tire that is 235mm wide, has a sidewall height of 129.75mm (55% of the section width), is a radial tire, and is intended for a wheel with a diameter of 18 inches.