Ok, the reason I suggested staying with 4 tires all around and not mismatching is because of at-the-limit vehicle dynamics. Let's say you have Brand A on the front wheels and they happen to be very sticky in wet conditions, wheareas Brand B in the rear does very poorly in wet weather. Under normal driving circumstances everything is fine. However when you near the limit of adhesion in either an aggressive avoidance maneuver, or perhaps take an off-ramp a little too fast, it can create spooky handling. Having the rear end of the car swing out suddenly (yes it's unlikely I agree) can be hard for many people to catch. Most modern cars understeer at the limit and thus the nose just pushes when you overcook it, but if you get some glue like tires up front and some rock-like tires on the rear things change. I used to race autocross years ago and a change of a few pounds of pressure would be enough to upset the handling of a car, nevermind when you mix brands. So that was my logic. Didn't want you to think I was just pulling things out of the air here.

Dave G. wrote:

Ok, the reason I suggested staying with 4 tires all around and not mismatching is because of at-the-limit vehicle dynamics. Let's say you have Brand A on the front wheels and they happen to be very sticky in wet conditions, wheareas Brand B in the rear does very poorly in wet weather. Under normal driving circumstances everything is fine. However when you near the limit of adhesion in either an aggressive avoidance maneuver, or perhaps take an off-ramp a little too fast, it can create spooky handling. Having the rear end of the car swing out suddenly (yes it's unlikely I agree) can be hard for many people to catch. Most modern cars understeer at the limit and thus the nose just pushes when you overcook it, but if you get some glue like tires up front and some rock-like tires on the rear things change. I used to race autocross years ago and a change of a few pounds of pressure would be enough to upset the handling of a car, nevermind when you mix brands. So that was my logic. Didn't want you to think I was just pulling things out of the air here.  

Ok I can agree with that reasoning, but I also agree it would have to be seriously mismatched tire types to pose the type of problem you described.

Also, I think you would be able to overcome this issue by buying similarly (or exact) rated tires (e.g. the tires I linked to above have a UTQG rating of 360 AA A, and the OE Michelins have a UTQG of 300 A A...pretty damn close if you ask me, the Sumitomo's have just a slightly better traction rating).

I also think things like even wear and tire pressure, like you mentioned, are more important. But in any case, point taken.

Thanks for all of your replies and explanation of why a hole on the edge is bad for the tire. A little surprising that a tire can be compromised such by a small hole in the edge of the tread, would have expected something like that from a pair of nylons - not a car tire. My goal was to keep all 4 tires the same, just hoping that a plug would have been sufficient. If the problem with a plug would just have been the possibility of air continuing to leak then it would be worth trying it and then replacing the tire if needed. But, if a hole in this area is prone to cause a blowout or tread seperation (which I didn't know) then certainly I would rather replace the tire than have my wife wreck because of it.

Looking at the price of replacement tires wasn't really a consideration when she was shopping for a new car. Not sure it would have made a difference though as it was her first new car since she bought her last one 17 years ago, so whatever car she wanted was fine by me.

Thanks again,
Joe

Everyone is saying, "New tire! New tire! New tire!" That, of course, is their choice; but, I disagree. For years, I used products like Fix-a-Flat to stop minor leaks, and, I leave the offending nail, or screw, in it (where I can keep an eye on it). Actually, the screw or nail, serves as its own plug. To use the product, let all the air out; then, put in the stop-leak. Check weekly. One caveat, the stop-leak may plug the air valve; then, you couldn't put air into the tire. Use a bicycle tire valve tool to put in another valve core.

It depends, to me, on how disposable your funds are.

I agree Kit. If the plug fails to take due to flexing it will manifest itself as a continued slow leak rather than a blowout. I truely believe its' better to plug it, keep the tires all the same, and keep an eye on it. It the plug does not take, the tire continues to leak, a decision can be made at that time.

I've heard recommended that if you plug a tire (in the tread area only), you should back it up with a patch on the inside. Sort of a belt-and-suspenders approach. The major point of a plug is that you can shoot it into the tire from the outside, without dismounting the tire. I'd be wondering what a plug would do to the integrity of a tread belt -- what would happen to the belt in the vicinity of the plug due to the distortion induced (shoving the belt aside)?

Fix a flat the other evil product of the tire world.
Chrome wheels the one is chrome in side & out. FAF will eat the lived day light out of the rim if left to long in side tire.
Alero came in for a slow leak, we found it at the bead area, two hour of grinding and cleaning it still leak. Due, to the FAF had pitted and eaten the rim bead area up to a point that all the grinding in the world would make perfect seal area. Sorry to say and thousand dollar later he had to a get a new rim. All becase FAF was left in the rim to long.
FAF is spose to heat up in the nail or what ever nail like product area in since seals the hole up so you can get to a tire shop.

It is not recommended that a tire with a puncture in the sidewall be repaired. It may sound harmless enough but one can bet their bottom dollar if a shop repairs that tire and it later fails leading to a wreck and injury/death that a lawyer will be sicced on the facility who did it PDQ.
With a flexing sidewall it is quite possible for that puncture to become enlarged.

Shops get sued for far less than that seemingly harmless fix. I worked for a dealer many years ago who allowed a customer to walk out into the shop and get something out of glovebox. The car was going to be in the shop all week waiting for parts.
The dealer actually walked this guy and his wife out to the car. The car was repaired, the guy paid the 500 dollar bill on it, and left happy; or so we thought.

About 2 months later we get a letter from an attorney in which the guy claims his wife had tripped over an "air hose that had been negligently left strewn over the floor". Imagine that, an air hose in a shop.
Of course the guy's wife never tripped over anything (I know because I was the one working on the car) but it cost my boss a couple of grand to settle this bogus claim. One can imagine what would have happened if it had been legitimate.

Those kinds of lawsuits make me feel sick to my stomach...for some reason, fraud like that just makes my blood boil.

I thought I would offer this link to a Tire Industry Association article: http://www...icNail.pdf

It says that one risk of plugging a punctured tire and not going through a recommended vulcanization process is that water may infiltrate around the wound. The steel belts are not stainless steel. Water would cause them to rust away and possibly lead to tread separation.

Regarding matching tires and using the OEM-installed brand, tires need to match each other and match the dimensions of the rims (including height and width), and they really ought to match the car maker's performance specification, but they do not need to match brand. Automakers specify tires based on traction, ride, noise, stability, speed rating, temperature rating, tread longevity, and whatever else they think might be important based on the intended use of the vehicle, and desired fuel economy performance (rolling resistance can affect that performance). For basic passenger cars, traction and stability are at the top and you don't want to compromise those. If you're doing heavy towing or loading up a truck bed, temperature rating is a serious consideration.

Regarding "serious mismatch," vehicle stability systems rely on information coming from each wheel's speed sensor. A tire with a circumference 1 inch smaller than all of the others, at 60 mph, will rotate maybe 1.25 to 1.5 percent faster than the other tires. It doesn't sound like much and maybe your car's stability control logic will adapt long term, or maybe that wheel will always be one nth of a rotation closer to being sensed as wheel slip, which could affect your car's braking and stability control responses. But the "serious mismatch" is as likely to occur if you put one new tire on a car that actually needs four (i.e., has 50K miles on the other tires). So pay attention to tire circumference in any case and check your owner's manual recommendations. I have an older car with all-wheel drive, and the owner's manual for that points out the need to pay attention to matching tire circumference. I also have a newer all-wheel drive, and that one adapts to wheel circumerence variations without any fuss on my part. So it varies.


But simply switching to another brand, e.g., changing from Pirelli to Continental, for example, to save money or to find a tire with a longer tread warranty, should be quite acceptable on a production car. If you notice, car makers are required to list your car's tire "specifications" on a label on your driver's door pillar or inside the fuel filler door. There are online tire resources, like tirerack.com, where you can find really substantive comparisons of tire ratings and performances across all of the brands. Good places to do this kind of homework.

Personally, I'd replace the tire even if only for peace of mind.

You have to keep in mind that the only contact with the road is that very small patch of rubber.

I have done so many repatch jobs because of the "gummy rope'" patch junk it is not funny.
Take it to two shops and if you get the same answer than yes you need a new tire.
Take it to Sears Auto Center they have a pretty good rules on tire patching and take it to real honest tire shop. Also ask what there "rukes' are on go or no go.
See if they use the speed rated patch.
Play fifty qestion with them.

The 18 wheeler next to you at 75 miles per hour likely has sidewall repairs on some of the tires.

I worked at a truck stop in the midwest (in nowheresville, ohio) and you should've seen some of the stuff we saw coming off the road . . . how there aren't more accidents due to worn-out parts, neglect, skipped maintainence . . . it's really beyond my comprehension. Tire plug or patch? Depends on the car, the use, the driver, the placement of the hole . . . the tread left on the tire . . . and how much the customer wants to spend. Rocketman

Depending on the amount of wear, I would either replace one or both tires. If you have sufficient wear to replace both, put the new ones on the rear and rotate the rears to the front.

Thanks for all of the responses. The tires had about 9000 miles on them, not the 10,000 to 12,000 miles I wrote in my initial post. Ended up just getting a new tire Staurday. The rear tire on the other side still had plenty of tread, so I only replaced the one tire.