Tires today are staggeringly expensive - due to the high cost of oil and the massive variety of sizes. The good news is, tires often last a lot longer than in the old days.
I have 65,000 miles on the Michelin tires on my X5 and they still show signs of more life left in them. But I will be swapping them out shortly. This is not an astounding tire life - they are warranted for a 60,000 mile tread life!
To me, this is nothing short of amazing, growing up in the era of bias-ply tires that lasted 30,000 miles - if you were lucky. Tires today are far superior to those in even the recent past.
Part of this is due to the new treadwear ratings. In the past, tires were sold on brand name and price, and most car owners looked for the best price on tires, unless they had a specific performance tire in mind.
Today, you can compare more than just price and brand, and this means more choice for you. But many folks make bad choices - and end up with tires they hate. And since tires are so expensive - and you generally can't take them back for a refund - it makes sense to shop carefully for tires.
For example, the Michelin tires on the X5 run about $250 apiece, mounted and balanced, for a total of $1000 to shod the car. This sounds like a lot of money (and it is, about 10% of the resale value!) but then again, they do last 60,000 miles or more. And the costs of mounting and balancing cheaper tires that don't last as long can cut into any savings on price.
And then there are issues with tram-lining (the tendency to follow line sin the road), road noise (roaring, tread noise) poor ride and poor handling. If you buy a cheaper set of tires and they end up doing one or more of these things, you are basically stuck for the next 50,000 miles with a crappy ride.
For this reason, it pays to stick with stock brand tires that came with the car. If you are happy with the tires on your car, there is no reason not to stick with that brand. Like with spark plugs, I generally recommend staying with the same brand and heat range, rather than experiment with some "improved" design or "bargain" brand. Experiments can go horribly wrong, and if they do, you are out all that money.
Bear in mind that for some manufacturers, the OEM tires may be different than the aftermarket replacements. Some manufacturers order special versions of tires (cheaper) for the original equipment. As a result, your aftermarket footwear may end up lasting longer than the stock tire. Ford got into some trouble with this over the Firestone tires they ordered for the Explorer, so perhaps this is less prevalent today.
The second thing is, to stick with stock sizes. As I noted in the tragedy of bling rims, going to oddball sizes to "improve" performance is risky, as if it backfires, well, you are out a lot of money.
In the photo above, I actually went to a slightly larger size tire on the M Roadster. Why? because I was not happy with the ride, handling, and tread life of the Continentals that came with it (bald before 30,000 miles). Plus the tires were so low profile, the sides of the rims scraped off. It was risky to switch brands, but I scored this set of Bridgestones at a silent auction for $250 - about the cost of one tire, under ordinary circumstances.
Your car may be offered with a number of size tires and rims - check your owner's manual or the tire pressure chart on the door jamb. Staying within these factory sizes is a good idea, if you to avoid problems.
By the way, read that tire pressure chart, get a tire gauge, and check your tire pressures regularly - it the simplest thing to do, and it could save your life, or at least save a tire!
It is always a good idea to avoid prescription tires, if you can. Many cars today come with these. The optional wheels on the "sport package" may look cool, but the tire size might be hard to find or very expensive to buy. Many European cars, such as BMW and Mercedes, have esoteric tire sizes, as do many performance cars. You may be shocked to discover that the tires on your sedan last only 30,000 miles and cost $300 each to replace. Look into this before buying a car. For most people, the difference in real-world handling is negligable.
I would avoid weird off-brands: Today, many folks swear by brands like Falken or Khumo - and some manufacturers are putting them on cars from the factory. I have had good luck with Michelins, Goodyears, and Bridgestones (but not their sister company, Firestone). But of course the quality of brands does change, over time.
And tire companies acquire other brands and then re-brand tires. I bought a set of Michelins right after they bought Goodrich and Uniroyal. They were an odd tire for a Michelin - whitewalls. And they did not handle or last as long as the original MXV radials that were on the car.
So you have to be careful to make sure that you get the real deal - the same make AND model tire as what you had - presuming you are happy with what you had. In that case, I had gone to a tire store and let some salesmen "sell" me on that tire - which they had in stock - rather than picking the tires I wanted and having them mounted.
Don't be afraid to order tires - places like The Tire Rack can get you tires and ship them by UPS to your house. They also are very helpful and provide great information on the phone and on the Internet. Most tire places or discount stores can mount and balance such tires, for a fee. Be sure to calculate this into your figuring, so you can compare overall cost.
Even if you don't order from the Tire Rack, they are a good source for price information. Before you buy from the local tire store, be sure to check out prices online. And tires are the kind of thing that give you plenty of warning before they fail - there is no reason to "BUY NOW!" when you can shop around.
Compare treadwear ratings - if you are going to switch to another tire brand or type. While some tires are cheaper than others, if they have half the treadlife, they really are no bargain. For most of us, longer treadlife is a better option overall.
Avoid racing or track tires - it is tempting, if you have a "performance" car to put high-performance racing or track tires on it. But such tires often ride very harshly, are loud, and tram-line. The good news is, many have a tread life of 20,000 miles - or less - so you won't have to live with them for long.
Be realistic about your use of the car. It was tempting to put Bridgestone RE-01R's on the M Roadster, but these are really racing or track tires - with short service life and a harsh ride. For a car that has been on the track twice in its life, it was not a good choice.
The real use of the car is for trips, going to the store, and the occasional drive. You don't need 10/10ths grip for joyrides like that - and overall operating cost of a car is important to anyone. So I went with a more pedestrian Potenza 760 tire, which rides nice, handles well, and has a 50,000 mile tread warranty.
Tires are getting to be a very expensive replacement item for cars these days. I can see where for many older clunkers out there, the cost of a new set of tires could easily exceed the market value of the car (!).
Back in the old days, the idea that you would junk a car because it needed new tires would be seen as foolish.
Today, I could see that as a distinct possibility - if re-tiring your car costs $1000 and the car is worth that, maybe it is time to retire the car instead.