Is it okay to replace one tire (of four matched tires) with a completely different model of tire?

If you've just driven over a screw you ought to be able to get the tyre repaired. I've had it done before and they basically glue a rubber plug into the hole.

As others have said, it's not usually a good idea to have mismatched tyres. The rules will vary depending where you are, but some countries (particularly France) won't allow mismatched tyres across the same axle. The UK allows them, but they must all be the same size and speed rating. Obviously I don't know what the rules are in the US or whether it varies from state to state. Mismatch between axles is less of a problem (my car has different size tyres between front and back axles as standard), but best avoided if you can. Most tyre dealers here will insist on fitting new tyres to the back axle if only two are being replaced.

The real answer is yes and no. It's perfectly safe to drive four completely separate tires as long as tires on the same axle are the same size. It's probably a good idea to get tires with the same tread life so that they wear evenly.

As far as the performance that Chris was talking about goes, the tires have an addition property between them. So if one had NO traction you'd have 50% performance, but if one was a snow tire and the other was summer you'd drive just fine in non-snowy conditions.

In my opinion, get matching tires per axle to save yourself from looking like an idiot.

Not recommended to just replace one, but unless you're pushing 9/10s of the capability of your car, you'd probably never notice the difference. When I was working construction, nobody would do full set or even axle set replacements. When you're having tires destroyed as fast as happens from all the loose nails lost at construction sites, it's foolish to replace all of them each time. At a minimum you end up with mismatched tread wear, and more typically you end up with a different brand as the make/model/size that one buys never seems to be available even just a couple months later. Sigh.

DT ik....NO..And always rotate your tires and never put a donut tire on the front if its a front wheel drive or back of its rear wheel drive

Can't comment on MooseLucifer's post (not enough reputation). Here's my two cents:

1. Tires of the same axle should always be the same size, ideally all 4 same.

2. A difference in tire wear across the axle has a minor effect on performance, because matched tires of the same size with differing tread depth will have slightly different Diameters, although the difference is rather small (twice the depth of the starting tread, if bald).

3. Having tires of differing sizes across the axle is not recommended to say the least. Bigger tires ROTATE more slowly than small tires at equivalent speeds, which means while traveling in a straight line, your differential will be constantly rotating which will cause it to wear out sooner. The mismatch will also negatively affect your car's "stance."

4. This is also why you don't want a donut on the drive axle. Donuts are much smaller than standard tires (also not rated past about 50mph). It is reasonable to use a donut wherever needed in order to get your car home and/or to a shop, nothing more. Donut tires are inferior in every way compared to standard tires.

5. Different size tires between front and rear axles is acceptable but will have some small impacts on performance and ride. As a general rule, wider and/or larger diameter tires have better dampening effects. Bumpy surfaces will cause the front and rear to behave in slightly different manners, which become more problematic at increasing speeds.

That's my 2...5 cents. I'm only here because Wal-Mart managed to install the wrong tire, and guess what? Yep, different sizes! Drive safe and smart!

The problem is magnified significantly on vehicles that are AWD (not transfer-case 4WD) that use viscous couplings.

Moving the worn tires to the rear and buying two nice new fronts over-excercises the viscous coupling, and can lead to failure of a VERY expensive part. Ask any late model Ford Explorer owner about this particular heartache...

This is a specific exception, and not exactly a direct answer to the OP question. However, it is an instance where replacing all four tires with the exact same model (or at least diameter) is prudent, taking into account the wear.

Aside from that, I see no reason why quality tires of the same ultimate diameter cannot be substituted, whether per axle, per side, or per vehicle. Granted, a snow and ice Nokia or General express hypermiler is not the same as a Michelin Pilot Zero summer-only gumbal - but I'm pretty sure that any all-season tire of the same diameter and size is safe enough on a prudently street driven SUV, van, or sedan.

If all of the tires are the same diameter, it will be very difficult to tell the difference. Of course, in bad weather, it might not be a good thing. They say to put two new tires on the rear axle of good quality to avoid spinning out in extreme conditions.

I have a 2011 Ford Focus, and while the car itself is good quality, I have now ruined two tires in three months by merely driving over a screw.

Ford offers no road hazard on their tires, so I am pretty annoyed with Ford.

Both Costco and Discount Tires advise me I should either replace all 4 tires, or at least replace 2 tires. They also tell me that the replacement tires should be of the same speed rating.

It appears your car does not have all-wheel drive. Some all-wheel drive cars require all of the 4 tires to have exactly the same rolling diameter, so even changing to an otherwise identical tire that has no wear, the new tire needs to have its tread depth reduced. If the all-wheel drive is electrically implemented (like in my Toyota RAV4 hybrid), then this need to have 4 identical tires doesn't apply.

Because your car doesn't seem to have all-wheel drive, I would:

• Change 1 tire, if the 3 good tires are like new (practically no treadwear), and if an identical tire (same brand, same model) is available.
• Change 2 tires and install them on the same axle -- if doing this, the 2 new tires should be as similar as possible to the 2 old tires that you're going to retain, but don't need to be completely identical. This also needs you to maintain the tires on the same axle, so when rotating tires, follow a rotation pattern that puts the tires always on the same axle.