Rolling resistance and tread life

[Falcon_LS]

I currently have Pirelli Scorpion STR tires (265/70-16 112H) on my Pajero. This is my second set, and they have been relatively good to me.

Because of local weather conditions, I refuse to roll on tires that are over 3 years old from the build date and will be replacing my current set before the start of summer. It's a while away, but with tires I like planning and budgeting in advance. Whilst I don't skimp on anything with any of my cars, where suspension, brakes and tires are concerned, I try to buy the best products I can afford.

As it stands, I've got two choices this year:

Pirelli Scorpion STR

Treadwear: 520
Traction: A
Temperature: A
Load Rating: 112
Speed Rating: H
COO: Romainia or Brazil

EU Tire Labelling Specifications:

Fuel Economy/Rolling Resistance: F
Braking under Wet Conditions: C
External Noise Level: 71 dB

Michelin Latitude Cross

Treadwear: 320
Traction: A
Temperature: A
Load Rating: 112
Speed Rating: H
COO: Poland

EU Tire Labelling Specifications:

Fuel Economy/Rolling Resistance: C
Braking under Wet Conditions: C
External Noise Level: 71 dB

The negative side of the Pirellis is that they harden over time, and some of the tread is ever so slightly torn. If you look at the tread pattern, the ribs on the side tend to tear from underneath and with a little effort, you can slightly lift about 5 mm or so off the base of the rubber. Put another couple of thousand miles on it, and the rib that was partially torn off the base of the rubber is no longer there. It also has the tendency to develop minor cracks in the tread.

Michelin tires in general tend to get a lot of good reviews, which is why I'm halfhearted about trying the Latitude Cross. What gets me though is the treadwear rating and pattern, but based on European standards, the Michelin has less rolling resistance than the Pirelli! Given the tread patterns, I would have thought the Pirelli would have better roll resistance than the Michelin.

This brings me to my question - the Michelin has a treadwear rating of 320 and the Pirelli 520. Given that the Michelin shines in the area of roll resistance, what sort of an affect would that have on tread life?

 

[CapriRacer]

First, tread pattern has very little affect on either rolling resistance or wear rate (unless we are talking about tires with lots of little tread elements like winter tires). While the difference in appearance between those 2 tires is striking, when you sort it all out, they have similar sized elements. Ergo, no difference in wear due to pattern.

Another thing to consider: Michelin tends to be conservative with their published ratings, where Pirelli tends to be aggressive. That means the Michelin UTQG of 320 and EU RR of C are probably low, while the Pirelli UTQG of 520 and the EU RR of F would be as high as the law allows.

Nevertheless, there are 200 points difference in wear between the 2 - and that is almost surely a significant difference. But the RR and traction values don't seem to line up with the technology triangle of treadwear/traction/rolling resistance, I would think that the treadwear rating difference is enough to answer your question.

 

[Falcon_LS]

Thank you very much, that certainly was an eye opener! Also had a read through the two "Rolling Resistance and Fuel Economy" sections on your website, which cleared that up further.