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Q: Special tires for '99 Camry LE V6?

The speed rating does not depend on softer compounds. And it may be that the methods used to improve the speed rating might also improve the handling and performance, but it does not have to be true. In my opinion, the easiest way to improve a tires speed rating is to change the aspect ratio. A tire with the same design, tread style, and material, but with a lower profile, will most likely (at least in my opinion) generate less side wall flexing and therefore heat. This may allow the tire to have a higher speed rating. A clear example of this is the Michelin Energy MXV4. The P205/65R15 and the P20/60R16 have almost identical ODs, identical tread wear ratings, identical traction rating, identical tread patterns, and similar load ratings. However, one is "H" Rated and one is "V" rated. Care to guess which is which?

What facts? You mean statements like "Changing from the O.E. tire speed rating to another performance level tire will probably change handling in areas such as:" "Will probably" is a fact? I 100% agree that changing performance level will affect performance. I even agree that in most cases tires with a higher speed rating are higher performance tires, but not because it has to be true. I also agree that tires of the same size and type but with different speed ratings will perform differently but not necessarily more so than tires of the same size and type from different tire lines. It is my opinion that you are using backwards logic. As I understand it, you are saying tires with a high speed rating are automatically high performance tires with superior handling and braking performance. I don't agree this is a valid argument. If you turn it around and say most performance tires with superior handling and braking performance also have higher speed ratings, then I am in agreement. I am also willing to concede that tires of the same size and type with different speed rating will have different, but not necessarily superior, braking and handling performance.

I agree with this. However, this has nothing to do with how well a tire handles or a tires braking performance. If you are arguing that tires with a higher speed rating, all other things being equal (size, load, inflation pressure) are less likely to fail due to heat build up than tires with a lower speed rating, then I am in 100% agreement with you. However, if you are arguing that tires with a higher speed rating automatically have superior handling and braking performance, I am not in agreement.

I at least am using some facts. You merely keep repeating your opinions as fact with no support whatsoever.

Michelins definition of a speed rating - "Speed rating: An alphabetical code (A-Z) assigned to a tire indicating the range of speeds at which the tire can carry a load under specified service conditions."

I don't see any mention of different handling or braking performance based on speed rating.

Also from Michelin -

"Can I replace the tires on my car with a lower speed-rated tire? "When replacing speed-rated tires, you must use replacement tires with ratings equal to or greater than those of the original equipment tires, if the speed capability of the vehicle is to be maintained. The handling of a performance vehicle may be different when the replacement tires are not the same speed rating. Refer to the vehicle owner's manual to identify any tire speed rating restriction that could affect the operation of the vehicle."

I agree with this statement, but I also don't see where it implies that higher speed ratings imply superior performance in other areas. Different performance is not necessarily better performance.

I have said my piece. We really aren't too far apart. I think we both agree it is important to purchase good quality tires of the proper speed rating for your car. The only area of disagreement is that you imply that a higher speed rating automatically implies superior braking and handling performance. This is an insupportable assertion. I doubt that even you believe that all V rated tires have better handling and braking performance than all H rated tires.

Ed

Reply to
C. E. White
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You are right. Probably on Mars or some alternate universe it is done differently. But on Earth, higher speed rated tires that are commercially available have better handling, cornering, breaking, emergency maneuvering, etc. This has been clearly documented and you refuse to believe it.

Give it up. You are a complete quack and a menace to society.

Reply to
Mark A

Site the documentation please. Go read the November 2003 CR article and tell me how you can make the above claim in light of the overlapping range of performance for H and higher speed rated tires. There is absolutely no hard relationship between speed rating and "handling, cornering, breaking, emergency maneuvering, etc." The relationship between speed rating and other performance characteristics is similar to the relationship between a vehicle's cost and it's overall performance. In most cases the tire with the higher speed rating will have have better performance characteristics, but it isn't always true. Likewise, higher priced cars usually have superior characteristics, but this is not always true.

Exactly how am I a menace to society. Is it wrong to recommend that tires be selected based on an overall evaluation of the performance characteristics instead of just assuming that a higher speed rating equals a superior tire? By warning people that the speed rating is only one characteristic that needs to be considered when purchasing tires? By trying to correct your misrepresentation that a tire with a high speed rating automatically has superior properties in other areas? Go back and show me where I have ever said that someone should buy low speed rated tires. Go back and show me where I have ever said that an individual should buy tires of a lower speed rating than the OE tires. In all respects, I have taken the a conservative and safe position. You have made a claim that are is supported by the facts. Calling me a "complete quack" does not make your misstatements true. You should make your point by presenting facts, not by disparaging those that disagree with you.

Ed

Reply to
C. E. White

In news:F4%Jb.43$ snipped-for-privacy@news.uswest.net, Mark A being of bellicose mind posted:

Hahahhahhah! Ed has too much hubris to yeild to your wisdom.

Reply to
Philip®

Philip,

There are industry standards for P metric tires. All tires of a given size and type should meet the minimum industry standards no matter how they are constructed. The "evil" tires installed on Explorers were P235/75-15 S105 Tires. The industry standard load inflation table for this tire size follows:

Cold Inf. Pressure Load

20 1543 23 1653 26 1753 29 1852 32 1940 35 2028

This is a tire industry standard, not a Ford standard, or a Firestone standard. A P235/75-15 Tire inflated to 26 psi is rated to carry 1753 psi at it's maximum rated speed. Since the Explorers used "S" rated tires, the maximum safe speed is 112 mph. Explorers are limited to 105 mph top speed by the vehicle's PCM.

The late 90's Explorers were rated for a total maximum rear axle weight of 2950 lb max. This means each rear tire should not be loaded more than

1475 lb. This is well below the maximum safe load of 1753 lb. Even if you derate the tires by 15% for light truck usage (10% is the typical factor used), the tires are still rated to carry 1490 lb. each. A properly loaded Explorer should not cause the failure of a good quality tire of the correct size and type if inflated per the original recommendations (26 psi).

The high failure rate of the Firestone tires, and the non-existent failure rate for the Goodyear tires in the same application make it is clear that the Goodyear and Firestone tires were not equivalent. However, it should also be apparent that the Firestone tires did not meet industry standards. Ford's recommended inflation pressures were not low by industry standards for comparable vehicles. In fact quite a few Toyota models recommended similar pressures for similar or even more severe applications. I don't have time to make you a complete list, but the following vehicles are among light trucks from Japanese manufacturers equipped with P metric tires with a 26 psi inflation pressure recommendation - 2000 Toyota Tundra, 1999 Toyota Tacoma, 1989-1993 Toyota

4Runner, 1994-2000 Nissan Pathfinder, 1996-2000 Nissan Pick-up, 2000 Xterra, virtually all Mitsubishi light trucks sold in the US, 1993-2000 Isuzu Rodeo and some other Isuzu light trucks, 90-92 Daihatsu Rocky.

Does all this have any applications to Toyotas? Yes! If you are driving a Toyota and installed Firestone P235/75-15 ATX tires on the vehicle as an after market replacement tire, be sure to monitor the tire pressure carefully. In congressional testimony it was alleged that ATX tires installed as replacement tires on other vehicles (like 4Runners) also experienced a high failure rate. There are almost 500 compalints against Firetone ATX tires in the NHTSA Database. Some as recent as last November (2003). Many of the complaints were for these tires installed on vehicles other than Ford Explorers. By trying to blame Ford for the bad tires, you are diverting attention away from the primary source of the problem and you may prevent someone from being wary of their Firestone ATX tires.

Regards,

Ed White

Reply to
C. E. White

Ford had final say on the inflation pressure recommendation in the Owners Manual and on the door jamb sticker which... was at the very bottom of barely acceptable to Firestone. Your best rationale is the ATX tires were less forgiving when run at pressures that would lower the tire's traction so top heavy SUVs would skid rather that flip suddenly.

Reply to
Philip®

Hey, back off of Ford, I need the big labor union support, ie UAW. I dont care if they kill people, just make sure they vote for me before they die.

Reply to
Howard "Nakita" Dean

I am not exactly sure what you are trying to say. This should not be that hard to understand. Either the Firetone ATX tires met tire industry standards and would have been safe when inflated to 26 psi, or they didn't meet industry standards and Firestone should have refused to sell them as P metric tires. If you actually read my previous note, you should see that a recommended a pressure of 26 psi for P metric tires used on a light truck was not unusual. Ford chose the 26 psi pressure because it provided the desired balance of handling, ride, wear, and safety. All vehicle manufacturers do this. If the tires had met industry standards,

26 psi would not have been a problem for a properly loaded and maintained Explorer. I can understand Firestone's reasons for trying to shift the blame. I don't understand yours. I do blame Ford for not adequately monitoring the Firestone tires. Over the years I have owned 4 sets of Firestone tires on a variety of domestic and import vehicles and so far they are batting 0% in my opinion. I can't imagine that Ford did not know that Firestone tires had very low Customer approval ratings, yet until the ATX debacle, they continued to make Firestone one of their chief suppliers. After the Radial 500 and 721 disasters, you would have thought Ford, and all other vehicle manufacturers, would have stayed away from Firestone tires like they carried the plague. On a positive note for Bridgestone (if not the Firestone brand), my Saturn came with Bridgestone tires and they are the best OE tires I have personally ever gotten on a new vehicle (second goes to a set of Goodyears on a Plymouth, and third to Bridgestones on my Datsun 280Z). When I need to buy replacement tires, I will certainly look favorably on Bridgestones. Hopefully I will be able to figure out which tires are really Bridgestones and which are Firestones (or maybe by then there will not be a difference - here's hoping).

Ed

Reply to
C. E. White

Isn't there some inbreeding between Ford and Firestone? The guys at the top are related or something, making Firestone the Ford preferred tire of choice at the time.

Reply to
Father Guido

Yes, there has been some serious inbreeding between the two families at the very top of the food chain. Firestone and Ford had been joined at the hip (or other body parts) from early in the 20th century until the recent flap.

Reply to
Mark A

Yes, Bill Ford's Mother is a Firestone. However, the Firestone family doesn't actually have anything to do with the tire company anymore. Bridgestone took it over years ago (1988). Unfortunately it appears that Bridgestone did not sweep out all the bad ideas. There was a time when Firestone made good quality tires ("The name that's know is Firestone, where the rubber meets the road"). Things started to go bad when Firestone tired to convert to radial tires on the cheap (the Famous Radial 500). Eevr sinee then I have alway thought Firestone was one step behind and always cutting corners in an attempt to make up for lost ground (721, ATX - just two more sucesses).

Here is a quote from a USA Today article -

"1978: Congress holds hearings on Firestone 500 problems. Firestone tells Congress the problems are consumer ignorance and underinflation. The Center for Auto Safety tallies 34 deaths blamed on Firestones. Firestone hires an attorney to quietly negotiate a settlement with NHTSA, limiting the number of tires that would be recalled while publicly maintaining the tires were not defective. Firestone agrees to recall 10 million Firestone 500 and similar TPC radials, plus 1.5 million private-label tires made for retailers."

If you change "Radial 500" to "Wilderness ATX" and the date to 1999, the same article would fit the ATX scandal. The biggest difference was than in 1978 Firestone tires were OE tires on a lot of different models.

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Ed

Reply to
C. E. White

But were the lists meant to be combined? Probably not. They tested different size tires for the different groups (the H-rated tires in

195/65R15 on a Honda Accord, and ultra high performance tires in some other size on a Ford SVT Focus). So, while the results were comparable within groups, they may not be comparable across groups (and tire size requirements probably mean that you may not have much choice in what type of tire to get for a given car anyway).
Reply to
Timothy J. Lee

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