I noticed today during my wheel swapping fest that allowing for mileage the Pirelli Scorpion STR 215/70R16 seem to wearing quite a lot better better (less) that the 50% more expensive Conti Cross Contact UHP 225/55R18.
Musing about this, rather than go out with a torch I decided to look up the treadwear index for each. It's taken a while to find, despite the new requirement for tyre labelling as shown here
goo.gl/rhI20
none of the vendors I looked at actually showed the wear index.
I found it eventually here so I'll pass it on,
www.safercar.gov/Vehicle+Shoppers/Tires/Tires+Rating
and the Pirellis do indeed have a higher (better) rating than the Contis - 520 vs. 420, though both are respectable, looking at some alternatives in the 300s.
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In real driving the indicators apparently aren't terribly meaningful.
Also, I've seen numerous (albeit anecdotal) stories of different tyres wearing at different rates on different cars, even different suspension set-ups on otherwise identical cars (eg. BMW).
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I've seen comments that they don't even compare across brands, which makes no sense at all for a standardised test.
The Michelin Latitude Tour rates 720 vs the Diamaris at 220. It seems unlikely that one wears at more than three times the rate of the other in real life.
Oh well, back to the drawing board.
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>> I've seen comments that they don't even compare across brands, which makes no sense at all for a standardised test.
But nor does NCAP ratings....
The NCAP rating only operates across the class of car - so a 1 star SUV could (will?) be safer than a 5 star super mini.....
www.euroncap.com/results.aspx
'Euro NCAP offers consumers the opportunity to compare the safety performance of similar mass vehicles with their chosen vehicle.'
Not many people are aware of that........
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Times change.
Doesn't seem that long ago that Pirellis were absolutely legendary for going bald in around half the time of anything else on the market.
Back in the '70s and '80s, performance cars were almost invariably fitted with Pirellis. Phenomenal grip, but at the expense of horrific wear rates. I guess that longevity is the major selling point in these austere times and they've had to go with the flow.
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IIRC the tread wear rating only applies to North America. Furthermore, it's a comparative figure for tyres produced by the same manufacturer, so you can't compare the ratings of one manufacturer with another.
Manatee's second link's to an American site and much of what they say won't apply this side of the pond.
If you want to do some serious reading I'd recommend the wheel and tyre bible: www.carbibles.com/tyre_bible.html
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Tyre treadwear ratings - Lygonos
