Time for new tires - let the debate begin

Thank you for the correction. I will make sure to tell my husband who is a Performance Application Specialist in the tire industry, that he has been using the incorrect terminology for the past 17 years.

As for getting mileage out of tires, I replaced the original Conti's on my Boxster with 35,000 miles on them. Of course, I kept the car properly alligned, keep the tires balanced and properly inflated and 95% of the driving is "spirited" country road driving, and not much track time.

[mjw930]

Originally Posted by creseida

Thank you for the correction. I will make sure to tell my husband who is a Performance Application Specialist in the tire industry, that he has been using the incorrect terminology for the past 17 years.

As for getting mileage out of tires, I replaced the original Conti's on my Boxster with 35,000 miles on them. Of course, I kept the car properly alligned, keep the tires balanced and properly inflated and 95% of the driving is "spirited" country road driving, and not much track time.

I didn't mean to say your husband was wrong but I checked everywhere I could and the term Performance Rating was never mentioned. I searched all the major tire manufacturer sites as well as the large tire resellers.

Performance Rating, by definition, would include many more factors than simply the speed and load ratings. The problem with something as subjective as a Performance Rating is there isn't an industry or engineering standard by which to measure one brand / model against another. Things like Speed Ratings and Load Ratings are finite and defined the the UTOG thus making it capable of being used accross tire brands / models.

If I'm wrong then please point me to a reference for Performance Rating that explains the way it's calculated as well as the actual ratings themselves.

The terminology changed several years ago. The term "speed rating" is a misnomer.

I've linked a few examples, but the industry has changed the name due to the fact that consumers tend to focus on one word that doesn't accurately represent what the rating stands for: "Speed". They see that word and say, I don't drive above 65 mph in my SL500. Why do I need a tire with a SPEED rating of 149+ mph?

http://expertpages.com/news/performance_tires.htm

8th paragraph down explains why it is now called a Performance Rating, and no longer called the "speed rating".


Same here : http://www.sizes.com/home/automobile_tires.htm




It isn't about a tire going 149 mph for 1/4 mile. Most people never go that fast, and most cars cannot go that fast. But they may still own cars with sophisticated suspensions requiring certain performance characteristics found in tires capable of sustaining a 149 mph rate of speed for one hour, under load, without compromising the performance of the tire, which is related to sidewall stability and integrity.

Performance does not necessarily mean high speed. Performance is simply how a tire perfoms under normal driving conditions. Important things like steering response/cornering, accelerating, braking and maintaining control in a panic situation. A better perfomance rating means improved response times. The sidewall doesn't have to play "catch up" under sudden braking and swerving manoeuvers in a higher performance rated tire. This would be the "slip angle", and less is better, which is what you get with a higher performance rating.


But, try telling this all to John Q. Public...or his wife. They still focus on the fact that they never drive above 65 mph and see absolutely NO reason to spend money on a tire that does. By calling it a performance rating, it emphasises the safety aspects, which John Q Public is far more responsive to.


A classic and true story about speed ratings: My husband was dealing with a Lady with her XJS Jaguar, and she thought she was All That. While my husband tried to patiently explain why she could not put S-rated $39 tires on her Jaguar, which required V-rated. She finally blurted out in a very demeaning manner (as if talking to some $5.00/hr peon), "Excuse me, but I own a Jaguar. I think I know what it needs better than you do . Have you ever even driven one?"

"Yes ma'am, I have, but I prefer to drive my Porsche or Maserati." and pointed to his car parked next to the building. That shut her up right quick.

[mjw930]

I'm sorry but neither of your links sway me. Both are individual's repsentation of the facts as they see them. What I've attached is the actual NHTSA federal regulations and description of tire markings. In all cases the DOT/NHTSA identifies the tires Speed Rating or Speed Symbol and makes no mention of Performance Rating

I think what we have here is a marketing name change from either the manufacturers or retailers to help the general public understand what this number means and I understand completely why they would want to do this.

Now, as some background, I'm an engineer that has spend a lot of time dealing with government regulations in the communications industry. This has made me very aware of using proper terminology as it relates to the regulations my systems must adhere to. I'm also a sports car enthusiast who has been enjoying and racing performance cars for roughly the last 30 years. If I seem stubborn then I guess I am but that trait has served me well in both my professional and personal life over the years.

I suggest we call a truce to this and get back to what we all can agree on, our love of Porsche's