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Another day, another pile of horsefeathers that I have to dig through.
I am replacing the tires on my car. The car is a Subaru Outback, which is a standard Subaru Legacy station wagon with a slightly comedic cosmetic option package and a chassis that rides one inch higher than the base model.
One of the cosmetic features is the use of oversize tires, to give the visual impression that the Outback is, if not a real race car, kind of like a real race car. Now, when you go to the tire store, the guy will look at the cosmetically large tires and say "Well, that's a load rating of 95. We can't put a tire on there that is less than a load rating of 95". Which is pure poopy because the only reason that there is a 95-rated tire on that car is because the carmaker's marketing department thought it looked cool.
The factory-spec tires on the baseline version of the exact same Subaru station wagon has a load rating of 87. Those tires hold up a car that is identical to my car except for some trim and styling. Probably not too well, but it holds the car up.
And if you try to get information of how to apply these load ratings to your car, you get unbelievable noninfo. One source says that if your car weighs 4000 pounds, buy four 1000 pound tires and you're done. Well, you're not done. Maybe the front of that car, where the engine is, might be 65% of the weight of the car, so the front tires would be overloaded. Not to mention the extra strain of the front wheels having to do the actual work of pulling the car around. And turning corners and taking bumps and all that. That recommendation to just buy tires to hold up the corners of a perfectly symmetrical mass is just too stupid.
And here's something else about tires: People sometimes say that the only difference among tires is the number of miles that you get out of them. I was once at a tire store and all the guy had was 50,000 mile tires, 75,000 mile tires, and 100,000 mile tires. All these tires had brand names and presumably positions in each manufacturer's product line, but he didn't want to talk about it. All this guy knew, and all he wanted to know, was miles. He clearly thought that I was a dope to have any other considerations.
Here, to me, is what makes a good tire: A good tire should be nice and soft in the vertical dimension (ride comfort), and nice and hard in the horizontal dimension (stability). I've had some tires that were very good in this regard (Pirelli, Hankook) and some that were horrible (Michelin, Michelin, Michelin).
After that, you can talk about traction and all that stuff, but if you're breaking traction in any modern car with any modern tires, you're a crazy person and it's pointless to talk to a crazy person.
PS: The only reason that this whole thing came up is that the car, as delivered, had an annoyingly hard ride. When it came to new tire time, I chose to replace the 16" 60-series tires with 15" 70-series tires. The outside dimensions of the new tires were identical to the old ones, but one inch narrower, so they didn't look so much like race-car tires.
The exercise was a resounding success. I didn't like the car before but now I do. It still handles perfectly well, but the bumps are not as sharp. Much more comfortable.