Hi all....just thought with all the various names of tyre out there I would pass on a little "tyre tech" I learnt over time. Firstly, there is only one way tyres pass certification and are deemed suitable to be sold to the public........a wet road breaking test measuring grip and stopping distance. Plain and simple and what all tyre ratings are based on!! This test translated in to a TREADWEAR rating which is stamped to all sidewalls of tyres; usually on one side. When buying tyres pay less attention to the 87, 91 or 97 stamped to the side followed by a letter, R, Z or W in most cases; although you should not go to a lower number rating than your car came fitted from the factory! The number relates to the casing stiffness and the letter relates to the speed rating; although with Aus. having a highway speed of 110 kph it baffles me why we get so caught up with buying tyres rated to speeds a lot higher. Next, don't get sold on the tread pattern and look. There are lots of brands pretending to be performance tyres and sporting aggressive tread patterns but in fact are no better than other so called passenger tyres. A classic example is the Pirelli P Zero Rosso which has a Treadwear rating of 340 as opposed to a Roadstone N1000 with a Treadwear rating of 280. As a guide one of the best tyres out there, the Continental Sportscontact 2 has a Treadwear rating of 100. Just to trigger some debate....the Cooper Tyres being advertised lately as long wearing etc have a Treadwear rating of over 700; which is how they last so long. Lets all wait for the Insurance industry to catch up with the marketing guys and start to reject accident claims when they find out that the car involved in the "failure to stop in time" accident and came fitted from the factory with tyres having a Treadwear rating in the 300 - 400 range now has tyres fitted with a Treadwear rating in the 700's.......and took over twice the factory claimed stopping distance to pull up in an emergency! I can go in to a lot more detail, including Treadwear ratings for most of the tyres sold in Aus today but I am also preparing a submission for the Insurance Industry which leaves me in a bit of a bind as I don't want to leave myself open to legal proceedings from disgruntled tyre companies........I will let the Insurance Industry and Transport Regulatory bodies in the country fight that battle. Just be careful the next time you go to a tyre retailer and get sold on a tyre that looks great but has a high Treadwear rating and will actually perform a lot worse than something else which has a lower Treadwear rating, will give the retailer a lot less sales margin and save you quite a few dollars
Good info WS :zlove: You might like to add something about tyre pressures and general tyre maintenance/safety inspection.
How does a higher treadwear rating reduce stopping times? I have 4 pirelli p zero nero allseason tires on my car, with a treadwear rating of 400, however they are the best gripping tires I have ever had, especially in the wet where I am able to corner at 60kph with only minor if any (usually none, but often I find oily intersections where the rear end slides out a tiny bit) without any problems, no complaints at all about their performance in the dry either, and my stopping distance isn't noticibly different from anything else I have ever used apart from obviously being much better than on budget tires.... Edit:Actually in the wet my stopping distance is better than on other tires I have used due to the nice deep groves that stop me from aquaplaning if I have to brake heavily.
In simple terms, Tread Wear is an indication(and a by-product)of 'grip/traction' between the tyre and it's contact with the road surface. A "soft" rubber compound will have greater grip(and subsequently, increased abrasion and wear)which translates as less life expectancy of that tyre. Less grip/friction with the road surface produces longer stopping distances/greater mileage at the expense of the increased risk of accident/injury.:br:
Right next to the treadwear: 400 it says traction:AA... which is apparently how well the car grips in the wet... I don't know about you but i'm much more worried about losing traction in the wet than in the dry. The information is handy to know and for that I thank you, but saying that insurance companies shouldn't pay out depending on the treadwear of a tire is just stupid imo. How would one go about even finding out what treadwear the tires their 23 year old car came with had... What I found googling about this stuff btw if anyones interested, seems handy about what all the shit on the side of the tire means. (also has a search thing to find the ratings of all the tires by any brand) http://www.safercar.gov/Vehicle+Shoppers/Tires/Tires+Rating
Good basic info on reading a tyre sidewall here: 2 things that are often overlooked... 1. When you're buying tyres, particularly 2nd hand ones (ie. if buying a set of used rims), check the production date. Generally you shouldn't use tyres more than 5 years old. Some say if they've been used it can actually be up to 10 years, but I wouldn't risk it. So if the 4 digit code ends in 07 or less (eg 1205 = 12th week of 2005), I would be refusing, replacing or using that info when bargaining to reduce the price on 2nd hand rims with tyres. I always check brand new tyres as well, just in case. 2. The recommended PSI is the COLD inflation pressure - if you're filling up at a servo that's not right near the start of your journey, the air inside the tyre will have heated up and expanded - so add another 2-4 PSI onto the recommended cold PSI amount.
When I hear about things that interest or are relevant to me I like to do my own research, and after looking into this quiet a bit (I am stuck on a 12hour shift at work on quiet day) I have discovered that apparently treadwear can only be compared between tires of the same brand, I have confirmed this from multiple sites and you can google it yourself, but have decided to cut and paste this from wikipedia because it gives the best summary (again, wikipedia wasn't my main source so don't give me that normal "oh wikipedia lol" shit): The treadwear rating or treadwear grade describes how long the tire manufacturers expect the tire to last. A Course Monitoring Tire (the standard tire that a test tire will be compared to) has a rating of "100". If a manufacturer assigns a treadwear rating of 200 to a new tire, they are indicating that they expect the new tire to have a useful lifespan that is 200% of the life of a Course Monitoring Tire. The "test tires" are all manufacturer-dependent. Brand A's rating of 500 is not necessarily going to give you the same mileage rating as Brand B's tire of the same rating. The testing is non-regulated and can vary greatly. Treadwear ratings are only useful for comparing Brand A's entire lineup against itself. Tread wear, also known as tire wear, is caused by friction between the tire and the road surface. Government legal standards prescribe the minimum allowable tread depth for safe operation. Tbh the whole article has some good info:http://en.wikipedia.org/wiki/Tire
Good point - also, the treadwear rating may be less than the maximum for that tyre. Why do this? Because if a tyre company has a 'long life' tyre with a rating of 600 and a mid-range tyre rated at 480, they might decide that the numbers are too close together, therefore not distinguishing the long-life tyre as worth the (probable) extra money. So they'll print 400 on the tyre wall.
Poor Chili - you must tire of people misspelling tyre. It's so tyresome... (tiresome? No, definitely tyresome...)
Ten years ago a UTQG treadwear rating could be taken as a reliable indicator of grip, but not so these days. Rubber compounds are a bit more complex now, and to suggest that a Roadstone has more mechanical grip than a P Zero Rosso simply because it has a lower treadwear rating is pretty dumb. Sport Compact Car did an awesome article on tyre grip, but since that magazine no longer exists this will have to do: http://en.wikipedia.org/wiki/UTQG
lol Chili, dont you get tired of posting something only to see halfway down the page someone else post the same thing like its a moment of inspiration that could never occur to any one else. And as far as "tyre" is concerned its like centre and colour all good English, words all spelt (also incorrect) incorrectly according to my British-English set version of windows. I get sick of it and my kids peering over my shoulder saying... " dad you have spelled that wrong ".... god that looks bad. its SPELT.
