Posted by David on December 19, 1997 at 07:32:19:
In Reply to: Re: Lexus E300: Is Pirelli P600 "H" M&S okay? posted by Lance on December 10, 1997 at 00:45:21:
A "H" rated tire my be fine for this vehicle, but to say that the speed rating has nothing to do with how the tire will perform in normal driving is absolutly absurd. It has EVERYTHING to do with a tire will perform in ALL driving. If a tire performs better at a higher speed doesn't it make sense that it will also perform better at a lower speed as well? In realation to tires of higher speed ratings vs lower ones, yes the ability to dissipate heat and hold together is porportionate with each speed rating catagory, but what must be done to a tire in order for it to have this ability is directly realted to how well a tire can provide traction for braking, acceleration, cornering, etc., etc., etc.. How well it reacts to imput form the driver, and does what you ask it to. We don't drive 150 mph in this country, but we do drive down the street where a child may run out in front of your car, a car may pull out in fornt of you , etc., with out warning. If I have to stop or manuver quickly, I want a tire that will do what I ask it to when I ask to. Yes there is a realtion in original equipment tires to a vehicles top speed capability, that originated in Europe (as did the speed ratings themselve's) and is maintained today. But just as a lower speed rated tire costs us consumers less $$, so would it cost the vehicle manufatuers, if they could save another $200 - $500 per vehicle with a different tire don't you think they would? If you put a "V" (149mph) rated tire on a car that came with a "S"(113 mph) rated, you wouldn't make the car go any faster but you would absolutely improve the way it handles. So if you put a "S" rated tire on a car that came with a "V" rated tire your not making the car go any slower, but you are diminishing it's handling ability - AT ANY SPEED!
With tires on the market today, you are not sacraficing nearly as much in other characteristics as you were 10 years ago with a higher speed rated tire. A all season "S" or "H" rated tire performs no better in snow than an all season "V" or "Z" rated tire. Noise and mileage are also not as directly realated to a tires speed rating as they were 10 years ago either. Harshness is realative and has as much to with a vehicles suspension as it does to a tires speed rating. I've installed "Z" rated tires on a car that came with "H" rated tires and improved the ride quality because it made the vehicle's suspension do the work instead of the tire. Tread wear ratings are not acurate enough to calculate a 23% increase in wear. A higher speed rated tire has the abilty to get as much mileage as a lower one. What happens is that you drive a higher speed rated tire harder, because it is capable of it, and therefore it gets less mileage than a lower one you are driving less agreesively. And thats at 50 mph not 150mph.