How to choose tires?

Hi everyone, I’m a total n00b to car ownership & maintenance. I ran over something yesterday that punctured one of my rear tires, and the AAA guy who just came to put my spare on doesn’t think it can be repaired. I’m going to ask my mechanic what he thinks, but in the meantime: if I do need to replace the tire, how the heck do I figure out which new one to buy? The car is a hand-me-down from my mom; she put on four new Kelly Charger GT tires in 2014 that are still in pretty good shape (other than this puncture). She says that since it’s a 4WD vehicle, I should replace two of the tires, not just this one. Is that right, or do I need to replace all four?

I do mostly city/suburban driving, minimal highway time. I’m in Philadelphia, so I do need to be able to drive in snow, but rain is much more of a concern. Do I need tires that say they’ll last 100,000 miles on the surface of Mars, or are the less expensive ones okay?

Looks like they still make that tire.

Find a tire store that sells your tire. Then ask that the tire be shaved down to match the diameter of the other three tires.

That way, only have to buy one tire.


That’s the best suggestion so far!

Seriously, I think @Tester’s suggestion is the best idea you are likely to see. If you can’t find the tire locally, maybe you can buy it on line at a place like Tire Rack. You do need to be conscious of tire diameter for an AWD car. If the diameter is too different, it will put too much stress on the drive train and will damage it. How many miles have you put on the car since 2014? BTW, it is not 4WD, but AWD. There is a difference, if you are interested.

It’s been about 21k miles since the tires were replaced in 2014. I’ll find out tomorrow whether they’re able to fix the tire; if not, hopefully I can find somewhere local that carries the same one.

I might be wrong about this, but I believe most of the places selling tires are not equipped to “shave” them

In fact, I wouldn’t be too surprised if it’s considered illegal in some areas

after all, arcing brake shoes is illegal in some areas

Correct, most tire stores cannot shave tires.

For this car, all of the tires have to be jut about the same diameter, ie, same tread depth.

You have to measure the tread depth on your 3 tires and compare that to the new one.

The subaru manual is vague about tires, only stating the following:
When you replacing or installing tire(s), all four tires must be the
same for following items.
(a) Size
(b) Circumference
© Speed symbol
(d) Load index
(e) Construction
(f) Manufacturer
(g) Brand (tread pattern)
(h) Degrees of wear
But obviously they are never identical. Even 4 new tires from the
manufacturer are not identical in circumference. There has to be some
tolerance. But Subaru is silent on this.

Tire Rack’s recommendation: Subaru: Within 1/4-inch of tire circumference or about 2/32-inch of each other in remaining tread depth. Given no other spec, we have to take this one as gospel.

If you can’t meet this spec, you have to replace all 4 tires. If not, you will have expensive repairs in the near future.

If the tread depth is too far off a used tire store or junkyard might have something, same model that will work

You can get a tire tread depth gauge at just about any autoparts store, and with this vehicle, you really should have one. A basic one only costs a couple of bucks and I don’t see any advantage to a fancy digital one.

If the circumference of the smallest tire is more that 1/4" smaller than the largest, you can (will) do serious (expensive) damage to the viscous drive in the transmission. If all four tires are the same brand/model/size, then you can go by the tread depth. This would allow a maximum deviation of about 2/32" from the deepest to the shallowest.

Your tire had 10/32" tread depth when new. If you measure all your tires and the most worn tire has 8/32" tread left, then you can put a new tire on without shaving it. If you have to shave too much off the tire to make it match, you would be better served buying all new tires.

If you or your mother has not been rotating the tires on a regular basis, then you need to check that tread depth ASAP. You could find that the tires on one end of the vehicle are already approaching the limit of difference and may need to be rotated soon. If this is the case, and the tire that is damaged is one of the worn ones, then you might want to buy two tires and keep the other good one in case another tire gets damaged in the future.

Does your mom still have the paperwork from the 2014 tire purchase? If so, it should have the car’s mileage at that time. If she doesn’t have the paperwork, the shop that sold the tires will have the mileage in their computer. From that, you can ascertain how many miles the tires have on them. Post that and we’ll be able to provide better guidance.

Many people put very little mileage on cars. How much your mom put on these tires will be key to determining whether you need one tire or two. Tester’s was an excellent suggestion, but as db said, I don’t think these machines are commonplace anymore. The last time I saw one was in about 1973 when I had a tire shaved.

“It’s been about 21k miles since the tires were replaced in 2014”

Taking that into consideration, I believe a new tire would have significantly more tread than the remaining 3

I wonder if a shop that deals with racers and/or off-road trucks would have the capability to shave a tire

Oops. My storebought eyeballs failed me. :confused:

@“the same mountainbike”

My own eyes are also rapidly degrading, as I said

I guess it’s called aging

I’m extremely nearsighted, yet I now can NOT see things directly in front of my face, not without removing my glasses

I suppose I’ll have to cave and get bifocals :frowning:

According to Kelly, the tread life is rated at 50,000 miles. Remaining tread would be a little over half based on mileage alone. Get a tire tread depth gauge and see if your remaining tires are around 6/32".

If you live in a city of any size, there will be one or more shops that offer tire truing or tire rounding…Google will find them for you…

Yeah, db, but my insurance company paid good money for these eyeballs!
I had to have both lenses replaced due to severe cataracts. They measure the eyeball and order the lenses custom based on the measurements. Truth is, they work great. I just missed the comment when I read the post.

If you end up buying a set of new tires, you need to be aware that every tire is a compromise of characteristics such as dry traction, wet traction, snow traction, ride comfort, noise, tread life, fuel economy, and price. If you bring up the tires you’re considering on Tire Rack’s web site, you can see the consumer survey results in each of these categories and pick a tire that matches your priorities.

@db4690, you can get progressive lenses that don’t have the bifocal line. Mine have 4 zones: distance, near for reading, and near not for reading. The last one is actually two zones on the sides of the lenses. You have to look pretty much straight ahead to get the distance correction. The optician warned me that some people don’t adjust to it, but I did very quickly. They are a lot more expensive than old style bifocals, if that plays into the decision. Progressive lenses go on sale periodically, and you can get them at half price.


Thanks for the info :smiley:

I was unable to get used to the progressive lenses, but I have friends who love them.
If you cannot adjust to the progressives, some places will replace them with demarcated bi/trifocal lenses at no additional cost. It’s worth asking up front.

Funny, I had no trouble adjusting to progressive lens. But I never had bifocals, so that may have made a difference.

OP: I agree with @lion9car 's suggestion to check out for shopping advice.They will also ship your tires to an installer near you.