Reply to "15 inch Tire Advice Needed"

Fritz wrote:

>[However a friend of min in Europe is a pretty big guy in the tire business and he was one of the key persons who organized the "after"-production of the Goodrich 275/50VR15's few years ago. They produced a very few of them, I believe about 1000 pc's. There gone as well and there is no other production in sight by now unless a group of people with appropriate investment is willing to complete an order.

>>>I believe the tires you are referring to are the (relatively) recent run of Pirelli P-7 in 275/55-15. These were made at the behest of Aston Martin, who used them as original equipment on their cars in the �80�s. Aston Martin still has a good supply of these tires, but they are expensive--about 450 UK Pounds each last time I checked. I�m not aware of any 275/50 VR15 Goodyear ever produced.

>However the alternative with any other tire, like the mentioned 305 H-rated one, is just a bad choice. How can people install such tires on a 10"-rim

>>>Uh, hello? BFG recommends a rim width of 8.5 inches to 11 inches for the 305/50. I admit it�s a bit of a squeeze on 8-inch wheels, although lots of people do it. I don�t recommend it since the back end of the car wiggles around somewhat with these tires on 8-inch wheels.

>and on a car which is capable to overrun the safety margin on a H-tire ??

>>>The safety margin you refer to is this: An H-rated tire is certified to run at 130 mph for TWO HOURS continuously. While it�s possible that some European drivers may have the opportunity to exceed this limitation, there is NOBODY in the USA who will ever come close to seeing the safety limits of an H-rated tire on the street. If you�re talking about running the Silver State race or a high-speed track like Pocono, that�s a different story.

And FWIW, I've seen 165 mph on H-rated Euro T/A tires more than once, with no problems.

>This is nut and shouldn't even belong to a bulletin board. FOLKS...DON'T INSTALL H-RATED TIRES on Pantera's !!!

>>>Overreacting a bit, are we? The early Panteras came with V-rated tires, but do you know what the speed rating on the Goodyear Arriva (original-equipment on the L-model Pantera) was? I�m pretty sure it wasn�t V-rated!

>Weight- and speed-ratio is a very serious thing. Don't hurt yourself or others. BE SAFE !!

>>>Obviously, somebody who has the best of intentions but is a bit ignorant on the subject. First of all, weight has nothing to do with speed ratings. As a matter of fact, the 305/50 is rated for a max load of 2601 lbs on EACH tire. Fritz, have you ever weighed a Pantera? I�ve weighed about 20 of them, and depending on a variety of factors, the weight on each rear wheel is about 950 pounds, plus or minus 50.

(Also, FWIW, a modern 17-inch performance tire like the Dunlop SP Sport 8000 335/35ZR17 has a Max load of only 1609 lbs)

Speed ratings are important if one is to ever drive his car fast enough to reach the threshold of danger. As I said, if somebody plans to drive at high speeds in Europe, or for extended periods in speed events in the USA, then they need to consider it carefully. But for a street-driven Pantera in the USA, H-rated tires are more than adequate.

(In fact, Carroll Shelby is currently selling his Cobras with S-rated tires, which should tell you something.)

Some people have the mistaken notion that the higher the speed rating, the �better� the tire, i.e. the more grip it will provide. There is NO direct relation between speed rating and traction. In fact, I have Yokohama A-008RS tires for my VW Scirocco, these are DOT-legal full-RACING tires, commonly found on cars running in the SCCA. They are super-sticky and will only last a few thousand road miles, and probably under 1000 open-track miles.

And they�re H-rated.

Looking at the BFG 305/50 again, you�ll see that it has a treadwear rating of 340 (the higher the number, the more durable the tire--my Yoko race tires have a treadwear rating of ZERO), with traction rating of �A� (the highest) and temperature rating of �A� (also the highest.) The high treadwear rating tells you that even though it earns an "A" traction rating, it won't stick as well as a super-duper performance tire.

These are certainly not GREAT tires--they can�t hold a candle to the performance of a modern 17-inch performance tire. But they are still very GOOD tires, certainly the equal of the vaunted Pirelli P-7 when it was at its best in terms of available traction and �feel� .

Furthermore, I can tell you that inflation pressures and tire condition are FAR more important than speed rating when determining the safety of a given tire. Pirelli P-7�s are renowned for having a very short lifespan. They will typically melt down to the cord in about 7000-10000 miles of driving. And when they are stored, they have a very bad habit of dry-rotting, much more so than most other tires I�ve seen.

I find it laughable that some people will drive around on rock-hard P-7�s whose sidewalls are cracked and whose tread blocks are literally rotting away from the carcass, yet believe that they are better off than the guy who is driving on NEW H-rated tires, because the old rotten ones wear a �V� rating on the sidewall. I would maintain that many P-7�s out there are fundamentally unsafe, even if brand new, if they have suffered from deterioration while in storage.

The simple fact is, there are no excellent tire choices available for the stock wheels. You can buy tires that fit perfectly, but are only H-rated (or even S-rated--112 mph for two hours.) If you are only driving the car below the speed rating threshold, then there�s no problem. Alternately, you can buy tires which are almost the same size as the original Pre-L tires with a V-rating; both Yokohama and BFG make a V-rated 235/60 tire which works reasonably well in the rear (my car is currently wearing these tires, borrowed; my 10-inch wheels with 305/50�s are in storage but will be mounted on the car later this year.)

(Early Panteras had a 215/70 or 225/70 rear tire, while the Arriva was roughly a 255/60)

If you seriously want to drive the car to its potential, then you either have to spend big bucks for the Aston Martin tires (and hope they have lasted while in storage for the past 5-6 years), or make the switch to 17-inch rear wheels (preferably with 16-inch front wheels) which is what most people are doing.

Mike Drew