Graham Matcham How to read tyre codes
Boy from the black stuff! – the manufacturers’ view
With over 30-years’ experience in both manufacturing and retailing motorcycle tyres, as well as running regular tyre support at classic motorcycle track events, what Graham Matcham thinks is worth listening to – I asked him five things, and here’s what he said.
Q: How old is too old for tyres?
A: Tyre condition is subject to the process of material change, which continues slowly through time. This will only have a detrimental effect on performance after a period of between five and 10 years. How long do they last? That will largely be dependent on storage conditions.
Q: What are the age limits on new stock held by tyre retailers?
A: There’s actually not a firm legal position, but responsible retailers protect their customers against aged tyres and the potential of reduced performance in a ‘from new’ purchase.
Q: Is there any kind of warranty offered on tyres for defect before they get too old?
A: Tyre producers are duty bound to offer warranty against any manufacturing defects during their useable life, typically a maximum of five years from date of production, although Continental Tyres offer five years from sale. There is an industry standard for making claims, whereby the tyre will need to be returned to the point of purchase. Obviously this presents a problem if purchased via the internet rather than the traditional way of buying from a tyre reseller in a face-to-face transaction.
Q: How can we make low-mileage tyres last?
A: The rate of performance change in a tyre can be reduced by keeping it in the dark and at a consistent temperature. Even in ideal conditions the tyre will not be at its best after a period of five years. Regular checks for correct tyre pressure will also help promote a longer life.
Q: What to look for in an older tyre to help decide if it’s good or not?
A: Typical signs of an aged tyre will be evident in sidewall cracking and an unnatural shine to tread rubber. We recommend replacing any tyres that are more than 10 years old.
Tyre codes started being added to tyres in the 1980s, usually found contained within a long oval shape. Here’s how to read them.
1980s: a simple three-digit code. The first two digits denote the week of production within the year (01 to 52), the last digit being the year in the 1980s e.g. 125 = 12th week of 1985.
1990s: Same as the 1980s, but as tyres would have been made with the same date stamp code they had 10 years previously something needed changing. So, rather inelegantly the 1990 tyre codes had a triangle added at the end of the three-digit code to delineate them from the 80s. Yeah, rubbish idea, huh?
2000 on: Things got sensible at the turn of the century when tyres went to the four-digit date code still used today. As previously, the first two digits tell you the week number of manufacture within the year and the last two indicate the year the tyre was manufactured.
So, on our DR600, 1906 means the rear tyre was made in the 19th week of the year 2006. The front tyre with 3400 is a year 2000 item made in the 34th week of the year.