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Law and Order Tests Police Tires, Part 7 of 10
Disclaimer: H-Rated Pirelli P6 Four Seasons
The 16-inch Pirelli P6 Four Seasons tire that comes as OE on the police Impala is V-rated. This tire was developed specifically for the police Impala. The 18-inch Pirelli P6 Four Seasons in a size that fits the police Charger is only H-rated and is tuned as the original equipment tire for the Ford Taurus.
Is it fair to compare an H-rated tire to other V-rated tires? Probably not. This is why we are pointing out the situation. No one combination of makes and models of tires were available in the speed ratings for all three police sedans. We got three out of four in the field of tires were tested. If a V-rated, P6 Four Seasons were available for the Charger, we would have tested it.
This raises the question, in the same make and model of tire, what are the differences between some sizes that are V-rated and some that are H-rated? According to Pirelli officials, the short answer is internal construction. In most cases, a stronger (or an additional belt) is used to allow the tire to go from a max speed of 130 mph (H) to a max speed of 149 mph (V).
So what if the H-rated P6 we tested had been a V-rated version? According to Pirelli officials, the transient response (slalom) would be slightly better. The H-rated and V-rated sizes in the P6 Four Seasons size line-up have the same tread pattern and a similar tread compound. According to Pirelli officials, the wet and dry braking between tires with these two different speed ratings would be “similar.” And the wet and dry handling between tires of the same model but two different speed ratings would be “similar.”
Pirelli officials were quick to mention that they make a truly high performance, all-season tire, the P Zero Nero M+S. See the online March-April 2006 issue of Police Fleet Manager for our high praise of this excellent tire after thousands of miles on a Ford CVPI. Since this tire is not OE on any current police vehicle, we opted to test the P6 Four Seasons, which is used on the Impala.
This situation, of course, means that this is not an apples-to-apples test between the H-rated P6 Four Seasons and the V-rated Eagle RS-A, V-rated Firehawk Pursuit and V-rated ContiProContact. This slight mismatch could not be helped and was unavoidable. However, the overall results for the V-rated Pirelli P6 Four Seasons tire would have been “similar” to these H-rated results had a V-rated P6 Four Seasons been used.
Published in Law and Order, Aug 2009
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