Cheap tire ideas? How do I even know when my car "needs" new tires?

[Fuzz]

I've got a 2007 Chevy Impala that I bought at a police auction (hey mustache, looking a little full there). I've had it about a year. The tires I bought it with are larger than standard for a sedan and all season. When I got my oil changed at Wal Mart, the guy advised me my tires were looking a little worn.

How do I actually know that I need to replace my tires? Should I look at getting a different size, assuming I could mount a narrower tire on my rims? The comments to some of the recent car posts/threads suggest that certain brands of tires would provide improve gas mileage and offset potentially higher costs.  Has anyone done the math on that? Anyone ever bought used tires? Discount tires? Sketchy craigslist tires?

Note, my job situation is in extreme flux and I may go from putting 1500 miles a month on my car to 200 miles a month, if I change positions soon. Ideally, I'd like to get a new job, not buy tires, sell the car and let the next person deal with it. My sense is at the low end of the used car market, spending $800 in nice tires adds approximately $0 to the resale value. How do I know how long I can put off this purchase? I don't want to be dumb about the risk of having a tire blowout and causing an accident.





 

[Two9A]

Wear of a tyre generally corresponds to how much of the original rubber is left on the tyre. There are grooves on the tyre, and checking how deep they are will give you an indication of how much is left.

In the UK, a tyre can come with anything from 6 to 10mm deep "tread", and the legal minimum before you are required to get new tyres by law, is 1.6mm.

If you can't see any grooves on your tyre, you're driving on bald slicks and will probably slide off the road at the first sign of rain, so it's advisable to replace 'em ;)

[atelierk]

This should answer your question: Measuring tread depth with a coin

[sockmunkee]

Aside from using coins, you can get a tire depth gauge for super cheap:
http://www.amazon.com/s?ie=UTF8&field-keywords=tire%20depth%20gauge&index=blended

Walmart should also list the depth of all four tires on the paperwork you received after the oil change.  If you're sitting at 2 or 3/32 then it's time.  I haven't dabbled in used tires - that's a bit more risk than I am willing.  However, you could go with someone you know who has worked with cars to ensure the integrity of the tire is decent. 

Personally, I'd rather just get the cheap brand at a reputable local chain (WalMart even).  All the chains offer deals every now and then - just wait for a "buy 3, get 1 free" deal and you'll save a good bit of cash.

Bald tires are really only a problem on slick roads but if you're a super safe driver,  you might be able to get away with such a crappy stopping distance:
http://www.youtube.com/watch?v=SRGxPqpieJw

[menorman]

Pretty much all tires have wear bars. If the tread is still above them, the tires probably don't need to be changed yet. At the same time, check to make sure they're not over- or under-inflated, which can wear the center/sides of the tire but not the rest. I personally usually run my tires to a bit below the wear bars. As for $800 on new tires, you must be doing it wrong. While I have bought brand new tires before, I've found that used tires can provide exceptional value. People buy new tires when their old ones are just fine and still have plenty of tread left. So when I arrive at the tire shop, all I have to do is pick the tires I want and they're $30/each for my size (which is actually a deflationary price because last time he charged me $35/each). Including all tax, installation fee, disposal fee, etc. I just got two "new" fronts a fortnight ago in this fashion. The tires I got would easily cost ~$200/each new after all costs are taken into account at most other tire places. I got an 85% discount in absolute dollar amount and about 70% when taking into account the wear on them.

[Bakari]

$800 is definitely not reasonable for car tires.
That's what I spent, and that's only because not only do I need 10ply load E range tires for my 5500lb work truck, but I decided to get low-rolling resistance tires because of an obsession with maximizing MPGs (and no, they will almost definitely not ever pay for themselves in fuel savings)

The only thing you are paying for at that price for regular car tires is brand name and bragging rights.

[twa2w]

Tires also have a 'best before' date - well not literally - they have a date of manufacture on them.  Tires should not be driven hard after they are a certain age - many articles on this if you google it.  Often tire shops will sell you new tires that are several years old - if you buy new or used, check the manufacture date - especially if doing high speed highway driving or driving in marginal conditions.
If you are buying new, there is no reason the manufacture date should not be within the last 6-8 months.  I have had success with buying tires off Kijiji - similiar to Craigs list - especilly for winter tires.

[Fuzz]

Thanks everybody. I'm cringing a little bit when I read this. The wear bar thing was definitely googleable. And I should have figured it out on my own. That's what you get for posting questions to the forum when you're drunk! And why my buzzed state was thinking about tire wear, I don't know.

Glad to hear that folks have had good experience with used tires. I only wore the front two out on my front wheel drive car, so I think I am going to rotate them. Possibly, I'll get cheapo new ones for the back, but I'm less concerned there.

[happy]

In Australia there is a standard about how much tread must be left: we use a match ie the tread should be the depth of the red match head. Personally I don't skimp too much on tyres - bald tyres are pretty dangerous - and the cops here will pull you up and slap a notice on you if they are too bad.

Rotating your tyres every 5-10,000km keeps the wear even. As does correct inflation.

My tyre place always tries to talk up regular wheel alignments to preserve tread, but I'm not sure how necessary this... I do much less than they say... but would be interested in what mustachians think about this.

[Bakari]

speaking of tire inflation:

use the maximum pressure listed on the tire itself, not the car's doorjam or manual.

You will get longer tire life, better traction, and better fuel mileage by using the tire manufacture's maximum pressure.

The pressure recommended by the car manufacturer is just meant to maximize ride comfort.