Tuning, Performance and Handling
Tyre Sidewall Markings:
Tyres have several different markings on thier sidewalls, this page explains what they are and what they mean.
Tyre Sizes
Tyre size markings are normally the largest of the marks on the sidewall and are made up of several numbers and letters, below is what these markings mean.
Example tyre size marking: 185/60 R 13 91 T.
| Marking | Description |
|---|---|
| 185 | The tyre section width in millimetres |
| 60 | The aspect ratio in % (the height of the sidewall divided by the tyre's width) |
| R | Denotes the tyre's construction type - in this case it's a radial |
| 13 | Rim diameter in inches |
| 82 | Load Index |
| T | Speed Rating |
Tyre Age
There is a 3 digit code on the sidewall of the tyre that indicates the month and year that the tyre was made. For example, 051 would mean the tyre was made in May 2001.
Speed Ratings
All tyres carry a speed symbol in the form of a letter indicating the maximum speed for which the tyre is intended. The table below shows which speed goes with each letter.
| symbol | km/h | mph |
|---|---|---|
| N | 140 | 87 |
| P | 150 | 93 |
| Q | 160 | 99 |
| R | 170 | 106 |
| S | 180 | 112 |
| T | 190 | 118 |
| H | 210 | 130 |
| V | 240 | 149 |
| W | 270 | 168 |
| Y | 300 | 186 |
Load Indices
The load-index figure imprinted on the sidewall of the tyre denotes the maximum load capacity of a tyre when driven at maximum speed. A list of load indices and maximum weights is give below:
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