No matter how good the car you're driving is, its overall performance is directly governed by the quality of its tyres and the grip they provide.
They are the main point of contact your vehicle has with the road and many people fail to realise that tyres require maintenance on a regular basis for them to continue operating at their peak performance. To best take-care of car tyres, you first need to understand the markings on Tyres-sidewalls. Your tyre sidewall contains all the information about your tyre that you’ll need. Here’s a little guide to what all those numbers and letters mean.
Standard Markings are:
- Tyre width
- Aspect ratio
- Radial construction
- Wheel diameter
- Load Index
- Speed ratings
Tyre Width: In the tyre sidewall indications, 1st three digit shows tyre-width of tyres. The width of the tyre is measured in millimeters. A tyre marked 225 will measure 225mm across the tread from sidewall to sidewall.
Aspect Ratio: Next 4th & 5th digit on tyre sidewall is Aspect Ratio that expressed as a percentage of the tyre-width. In the example, if aspect ratio is 65, it means that profile height of the tyre is 65% of its width.
Radial Construction: In Tyre sidewall marking Letter 'R' indicates that the tyre is manufactured with a radial ply construction. Radial tyres are constructed with the cord plies positioned at a 90 degree angle to the direction of travel to give the tyre additional strength
Wheel Diameter: The tyre's wheel diameter is measured in inches taken from the wheel flange where the tyre is seated to the same point on the opposite side.
Load Index: Load Index of car tyres directly relates to the maximum load carrying capacity in Kg. On tyre’s sidewall, Load Index is mentioned just after the diameter. In the simple mean, Load index provides the information on the maximum weight capacity for the tyre.
Speed Rating: The speed rating is an important marking of car tyre. It's indicated by alphabet at the end of the tyre size and it represents the maximum speed capability of the tyre. For example , if a tyre marked with speed rating of V, has a maximum speed of 240km/h. So, it is recommended that while buying a new tyre speed rating must be matched with vehicle speed capability.