A couple of weeks ago, I did a piece titled, “Driving In The Rain”. In my usual practice during the rainy season, I wish to focus on tyres because of the need to guard against tyre burst or blowout. Tyres are among the most important part of the vehicle but unfortunately the least understood. Without the tyres, your vehicle is useless. You need the tyres to start, move and stop the vehicle. So buying tyres is a task you need to undertake very carefully otherwise your safety and that of other could be put in great danger.
Before you buy any tyre, give serious consideration into the size of the tyre, the age of the tyre and the physical conditions of the tyre. Tyre size: On the side wall of your tyres, you will see figures like 215/75/15r, 195/65/14r and so on. These are designations for your tyre sizes. Check your own tyre to know what is written on it. The first figure from the left is the width (from side wall to side wall) of the tyre in millimeters; the middle number is what is known as the aspect ratio used to calculate the height of the side wall of the tyre. The last number is the ream diameter.
When you go to buy tyres you will mention all of those figure to the tyre seller so that he will give you exactly what you want, there are various sizes of tyres in the market that can fit your type of vehicle but that does not mean that those sizes are good/safe for your vehicle.
Every vehicle has tyre sizes specified by the vehicle manufacturer. If you check the tyre placard by the end of your driver’s door, hood or the vehicle’s manual, you will see the specification for your vehicles tyre sizes, please stick to these specification while buying replacement tyre. Don’t let the tyre seller give you something else.
The manufacturer of your vehicle have taken a lot of factors into consideration before specifying your vehicle tyre sizes. If you change that, your vehicle may not handle well, may be risking a blowout and a crash. Changing to fatter tyres like some people do may look better but not safer. In most cases, the manufacture provides alternative sizes should you not find the original sizes the vehicle came with. The tyre placard will specify these alternatives.
However, there are some calculations you can make to get sizes apart from what the manufacturer specified that will give you the same result as the original specification, but you need to know how to do the calculations otherwise stick to the original specification. Even more important that the size of the tyre is its age. Unfortunately most motorists as well as tyre sellers themselves don’t know how to check for the tyre age, they depend only on visual inspection of the physical conditions. Some will invite a vulcanizer who will do a press up (or is it press down) on the tyre to certify if it is okay what a wrong and dangerous thing to do.
Why the emphasis on the emphasis on age of a tyre? Just as age could disqualify and otherwise promising marriage mate, age will disqualify a tyre even if every other thing seems alright from a visual inspection. Do not be deceived by a tyre’s looks every tyre has an effective life span beyond which you will be entering the danger zone. As a general rule, any tyre more than 6 years old should be discarded. This rule, however, applies to quality tyres with branded known names. Less quality tyres of course, may not last that long. So how do you determine the age of a tyre?
Unlike humans who can hide their ages, every tyre provides information about its age but in a coded form. Look at the side walls of your tyre and check for the letters dot. Look around the dot (to the left or to the right) until you get to either a three digit or four digit number boldly imprinted on the tyre without any alphabet attached to it. Some tyres though, may not have the letters dot printed on them. Just look around the side wall you definitely will see a 3 or 4 digit number clearly imprinted on the tyre.
The 3 or 4 digit number is the code designating the date of manufacture of the tyre. Since it is a code, you need to decode it to get the age of the tyre. So lets decode it. If it is a 3 digit number, check to see if it has a triangle sign attached to it. A 3 digit number without a triangle means the tyre was manufactured in the 80’s , the first two number from the left tells you the week in the year while the last number tells you the year in the 80’s.
However, if you have the number 341 (without a triangle) it means 34 week of 1981 (34 is the first two numbers from the left indicating the week while 1 is the last number indicating the year in the 80’s) if the 3 digit number has a triangle it means the tyre was made in the 90’s. So 341 with a triangle means the tyre was made in the 34th week in 1991. If it is a 4 digit number, it means the tyre was made any year from year 2000. For example, a tyre with 2302 means the 23rd week of year 2002. The first two numbers from the left indicating the week while the last two numbers indicating the year. Four digit numbers do not have triangle signs with them.