abbychumz
Elder Lister
TYRES. We see them every day on vehicles and are the only point of contact between the car and road. On them, there are a lot of numbers: 225/45/R19 or 92W and many others. What do these numbers mean, what should you check before buying a tyre.....
The big numbers 225/45/R19. The 1st number 225, is the width of your tyre track, the surface that touches the ground, it's in mm - 225mm. The 2nd number 45, is the rim and top of the tyre, thickness (sidewall) if you will, it's a %age, 45% of the width (225) of your tyre...
...finally R19. This is the inner diameter of the tyre, where your rim fits. R means radial, which refers to how the tyre is made, over 99% of tyres are radial and will have R. The 19 is in inches, 19 in wide.
What about the 93W? This is the Load-Speed rating. 93 is the max load the tyre can bear safely, 93=650kg. The W is the speed rating, most passenger cars have a rating from N. In this case a W can sustain a maximum speed of 260KM/h safely.....
The load rating is duplicated again on the tyre (Max Load). The pressure indicated on the tyre is the MAX pressure, not the recommended pressure. This is a Do NOT inflate beyond 44PSI in this case. Note the MAX pressure rating is when the tyre is cold.
Tyres have a shelf life of 6-7yrs. After this time the rubber and tyre components may have degraded such that the tyre may not be safely used. When buying tyres check the date of manufacture, usually circled. In the tyre below the number is 3507...What does it mean?...
The tyre was manufactured in the 35th week of 2007. Or in the tyre below, the 8th week (February) of 2020, in this case, the tyre shouldn't be used after 2027, even if the condition of the tread is still in good condition. Degraded rubber is one of the reasons for tyre bubbles
Ocassionaly tyres have letters before the big numbers, e.g. P205/70R15. P designates it's a passenger tyre, while LT is a light-truck tyre.
OFF-ROAD (4WD-MT-AT) TYRES size designations are often written differently than normal tires. Something like 35X12.5R20. This is because this is a metric system measurement. Overall tyre diameter-35in, Width-12.5in & rim diameter 20in. This would be referred to as a 35in tyre
The big numbers 225/45/R19. The 1st number 225, is the width of your tyre track, the surface that touches the ground, it's in mm - 225mm. The 2nd number 45, is the rim and top of the tyre, thickness (sidewall) if you will, it's a %age, 45% of the width (225) of your tyre...
...finally R19. This is the inner diameter of the tyre, where your rim fits. R means radial, which refers to how the tyre is made, over 99% of tyres are radial and will have R. The 19 is in inches, 19 in wide.
What about the 93W? This is the Load-Speed rating. 93 is the max load the tyre can bear safely, 93=650kg. The W is the speed rating, most passenger cars have a rating from N. In this case a W can sustain a maximum speed of 260KM/h safely.....
The load rating is duplicated again on the tyre (Max Load). The pressure indicated on the tyre is the MAX pressure, not the recommended pressure. This is a Do NOT inflate beyond 44PSI in this case. Note the MAX pressure rating is when the tyre is cold.
Tyres have a shelf life of 6-7yrs. After this time the rubber and tyre components may have degraded such that the tyre may not be safely used. When buying tyres check the date of manufacture, usually circled. In the tyre below the number is 3507...What does it mean?...
The tyre was manufactured in the 35th week of 2007. Or in the tyre below, the 8th week (February) of 2020, in this case, the tyre shouldn't be used after 2027, even if the condition of the tread is still in good condition. Degraded rubber is one of the reasons for tyre bubbles
Ocassionaly tyres have letters before the big numbers, e.g. P205/70R15. P designates it's a passenger tyre, while LT is a light-truck tyre.
OFF-ROAD (4WD-MT-AT) TYRES size designations are often written differently than normal tires. Something like 35X12.5R20. This is because this is a metric system measurement. Overall tyre diameter-35in, Width-12.5in & rim diameter 20in. This would be referred to as a 35in tyre
