2pac

What does the letter indicate on the tyres? I currently have W tyres but have ordered more off the net but have ordered Y's. Have i made a cockup and ordered ones that wont fit? All the numbers match its just the letter is different.

Could someone explain the letters in simple terms for me.

Many thanks

Dill_typeR

the letters are the speed rating of the tyre given for the application they were designed for.

Check to make sure, go on any tyre manufacturer website, and it should have the info on there.

try this

TYRESAVE: Tyre Speed Ratings

(edited to add site)

2pac

perfect response thank you very much, looks like i just got a tyre one up from what i had. Many thanks.

Dill_typeR

nay probs

Yamarashi

Just a bit of extra info for you regarding getting new tyres is the load index. Impreza's are in need of quite a high load index tyre of about 88 and upwards. This is what a lot of people fail to check when buying new tyres.

2pac

well the website i got them from (blackcircles)_ makes you put in your car make/type and tyre size then lists all the appropriate ones they have so i assume these will be ok. thanks for the help.

The Trooper 1815

iTrader: (31)

Some extra Stuff too!

Sidewall Markings
Most people know what 205/55VR16 91W means. But what about the rest of the information that is given? Here we try to explain what it all means:Treadwear
Treadwear is a measurement of tread durability. Tested against an industry standard, the assigned numerical guide grade indicates how well the tread lasts compared with a reference standard of 100. A treadwear rating 200 means the tread wears twice as well as the standard. Actual wear depends on the conditions under which the tire is used. Driving habits, service practices, differences in road surface and varying climates all affect treadwear.
Traction

Traction is a measurement of a tire's ability to stop on wet test surfaces of asphalt and concrete under controlled conditions. Traction grades are assigned by the UTQG system and branded on the sidewall. Traction grade is determined only for straight-ahead, wet braking on concrete and asphalt. It doesn't include cornering, which may also be an important customer performance need.

• Traction Grade A: The tyre performed well on both surfaces
• Traction Grade B: The tyre performed well on at least one of the surfaces
• Traction Grade C: The tyre performed poorly on one or both of the surfaces

Temperature Resistance

The UTQG also provides a measure of resistance to heat generation under normal operating conditions. The test is conducted under predetermined standards for inflation and loading. Excessive speed, underinflation and overlaoding can all cause adverse heat build-up. Sustained high temperatures can reduce tyre durability. Resistance grades are branded on the sidewall.

• Resistance Grade A: The maximum performance level indicating the tyre withstood a half-hour run at 115mph without failing.
• Resistance Grade B: The tyre passed 100mph but not 115mph.
• Resistance Grade C: The minimum performance level indicating that the tyre failed to complete a half-hour at 100mph.

Certification
"DOT" is branded on the tyre's sidewall indicating the tyre is certified by thr Department of Transport. Following the DOT branding is a serial number designating the tyre manufacturer, manufacturing plant, tyre size and date of manufacture.
Additional Tyre Labelling Conventions
If a tyre is rated for safe performance in mud and snow, it will be noted on the sidewall of the tyre with either M/S, M+S or M&S. A tyre is certified under the definitions set forth by the Rubber Manufacturers Association (RMA).