How to Read Your Tyres..
Ever wondered what the markings on the side of a tyre mean?
205/55 R 16 91V This is the size and characteristics of the tyre:
205: This is the section width of the tyre. That means the overall width of the tyre in mm.
55: This is the aspect ratio of the tyre. That is the sidewall height of the tyre as a percentage of the section width.
R: This mean the tyre is of Radial construction.
16: This is the internal diameter of the tyre.
91: This is the load index. How much weight the tyre can carry. These go from a load index of 50 (190kg) up to an index of 169 (5800kg)
V: This is the speed index. This indicates the maximum speed that the tyre can sustain for a ten minute endurance without coming to pieces and destroying itself, Speed ratings vary from "L" (75mph) to "Y" (186mph)
As well as all that, you might also find the following embossed in the rubber tyre marking:
The temperature rating - an indicator of how well the tyre withstands heat buildup. "A" is the highest rating; "C" is the lowest.
The traction rating - an indicator of how well the tyre is capable of stopping on wet pavement. "AA" is the highest rating; "C" is the lowest.
The tread-wear rating - a comparative rating for the useful life of the tyre's tread. A tyre with a tread-wear rating of 200, for example, could be expected to last twice as long as one with a rating of 100. Tread-wear grades typically range between 60 and 600 in 20-point increments. It is important to consider that this is a relative indicator, and the actual life of a tyre's tread will be affected by quality of road surfaces, type of driving, correct tyre inflation, proper wheel alignment and other variable factors.
The New EU Tyre Ratings
This new regulation will bring a major advance in consumer information on tyre safety (wet braking) and the tyre’s impact on the environment (rolling resistance and external noise).
These new Labels will be similar to those used on household appliances and will allow the consumer greater choice and knowledge when choosing tyres for their vehicle
RunFlat Tyre Specific Markings
DSST: Dunlop Self Supporting Technology
EMT: Goodyear Extended Mobility Tyre
RFT: Bridgestone Run Flat Tyre
ROF: Run On Flat
RSC: Runflat System Component
SSR: Continental Self Supporting Runflat
ZP: Michelin Zero Pressure
DOT Codes & The 5 Year Shelf Life
As part of the DOT code (Shown in Top Image), there is a tyre manufacture date stamped on the sidewall. Oddly this code is sometimes only one one sidewall so you might need to get under your car and look at the inward-facing side of the tyre.
Take a look at yours - there will be a three- or four-digit code.
This code denotes when the tyre was manufactured, and as a rule-of-thumb, you should never use tyres more than 5 years old.
The rubber in tyres degrades over time, irrespective of whether the tyre is being used or not.
The tyre might look brand new, but it will delaminate or have some other failure within weeks of being put on a vehicle.
Reading the code.
The code is pretty simple. The three-digit code was used for tyres manufactured before 2000. So for example 1 7 6 means it was manufactured in the 17th week of 6th year of the decade. In this case it means 1986. For tyres manufactured in the 90's, the same code holds true but there is a little triangle after the DOT code.
So for this example, a tyre manufactured in the 17th week of 1996 would have the code 176 ^
After 2000, the code was switched to a 4-digit code. Same rules apply, so for example 3 0 0 3 means the tyre was manufactured in the 30th week of 2003.
Interesting note : in June 2005, Ford and GM admitted that tyres older than 5 years posed a hazard and from their 2006 model year onwards, started printing warnings to this effect in their drivers handbooks for all their vehicles.
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Who Makes Your Tyres?
There are many brands of tyres, but they are not all seperate companies, Many of the Premium Brands ( Michelin, Bridgestone etc..) actually cater for every price range on the market and have their own mid-range and economy brands sold under different names, Although not a full and concise list these are the most popular examples...
Michelin ( Based in France) Own the brands Michelin, BF Goodrich, Kleber, Kormoran, Enduro, Nexen and Riken.
Bridgestone ( Based in Japan) Own the brands Bridgestone, Firestone, Daytona, Federal, Hero and Europa.
Goodyear ( Based in the USA) Own the brands Goodyear, Dunlop, Fulda, Falken and Kelly.
Yokohama ( Based in Japan) A Japanese Sports one brand company.
Pirelli ( Based in Italy) Own the brands Pirelli, Ceat and Courier.
Cooper Tyre ( Based in the USA) Own the brands Cooper, Avon and Mastercraft
Continental ( Based in Germany) Own the brands Continental, Uniroyal, General Tyre, Event, Gislaved, Barum and Semperit.
Toyo ( Based in Japan) A Japanese Sports one brand company
Kumho ( Based in Korea) Own the Brands Kumho and Marshall
Nokian ( Based in Holland) An economy brand made in the Netherlands by the mobile phone company Nokia