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Replace 1, 2 or 4 tires?

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#1
Smacked a pothole today and got a flat. The rest of my tires have between 7/32 and 8/32 left. Tires have about 10k on them (Firehawk Indys).

One of the other tires does a small scrape on the sidewall from last year and several 1000 miles ago (pic below).

Not sure if i should just replace the one tire or if it makes more sense to replace the pair, or if I should really be replacing them as a set. Any insight is appreciated
image0 (4).jpeg .
 


rallytaff

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#2
I always replace all four tyres. I have two sets of tyres in my garage with only 3 tyres in each. Now I have to trash them (they're nearly brand new) because I can't find the fourth to make the set. Makes me want to buy FIVE next time in case the model goes out of production!
 


SteveS

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#5
It's a daily driver street car. The tires are what, half used up? You can replace a pair (never a single tire unless it's less than 1000 miles or so on the others) to save money. If you do that, you can't rotate because you have to keep the better tires on the front until the wear evens out. That's the way people do it for frugality.

If the tires are almost done (i.e. total life is only 15K anyway) then you are better off just getting a full set.
 


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#6
Another vote for replacing the pair. However I was recently informed that some tire shops have the equipment to equalize the running diameter of a new tire to an existing set. Basically they mount the new tire and put it in a machine that grinds the tire down and uses CNC methods to match the cross tire profile.
 


Erick_V

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#7
Also agree with just replacing 2. You’re not being stingy by doing that. The other tires have plenty of life and you’d be wasting them by replacing all 4. If you have that kind of money sure, replace all 4. This isn’t an AWD car, you’ll be fine. If you’re only street driving the car the 2 new and 2 old tires isn’t going to make a difference you’re going to feel. I already have 6 tires, 3 spares and 4 wheels w tires taking space in my garage, not including my other car that is surrounded by all that stuff, no need for extra junk in the garage. Replace 2, maybe keep the good one and go on with your life
 


gtx3076

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#8
I've been on a 2 replacement kick. New one in the rear, old ones with plenty of tread left, to the front. I would only consider all 4 if they were somewhat evenly worn, or the rears were beginning to dry rot from being on for so long. All of my cars are FWD so the rears tend to have plenty of tread.
 


Dialcaliper

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#9
I’m going to go against the grain here. Normally I’m a replace all 4 kind of person, and I selectively rotate tires to try and get them all to hit the wear bars at the same time.

The cut in your other tire is in the thick rim
protector area that’s pretty much cosmetic - as long as it hasn’t knicked a belt, it’s probably okay.

at 7-8/32, your tires are so new that you could probably get away with a single new tire, just make sure to put the new Indy 500 (9/32 new) tire on the right front (which tends to wear fastest because torque steer/wheel spin) and the next deepest 8/32 tire on the front driver’s side.


If you monitor the tread depths carefully, in about 5000miles, you’ll have a hard time telling which tire is which.

If that skeeves you out, or you don’t want to spend the time monitoring tread depths, then buy two tires, keep the two with the deepest tread depth.

How bad is the pothole flat tire? If there’s a big cut and belt damage or a sidewall blowout, chuck it. But a tire with intact belts from a small tread puncture (like a nail) can be safely patched and be good as new with an internal patch by a competent tire shop - I usually go to my local race tire shop because they don’t try to - a quality internal tire patch can even be safe for competition use. But don’t put up with an external mushroom or or string plug unless you’re just trying to nurse a tire on its last legs until you can buy a new set.

The other option that someone mentioned above is to buy a new tire and have it shaved to depth which any competition tire shop or other well equipped shop can do using the same equipment that they use to shave the tread down on race tires.

If you don’t live near a good shop, apparently Tire Rack can do it for you for $25-35 a tire if you call or email.

https://m.tirerack.com/tires/tiretech/techpage.jsp?techid=259

But honestly at the near new tread depths you’re listing, you probably don’t need to shave (they typically only guarantee within +\-1/32 of target depth
 


Last edited:
OP
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Thread Starter #11
I’m going to go against the grain here. Normally I’m a replace all 4 kind of person, and I selectively rotate tires to try and get them all to hit the wear bars at the same time.

The cut in your other tire is in the thick rim
protector area that’s pretty much cosmetic - as long as it hasn’t knicked a belt, it’s probably okay.

at 7-8/32, your tires are so new that you could probably get away with a single new tire, just make sure to put the new Indy 500 (9/32 new) tire on the right front (which tends to wear fastest because torque steer/wheel spin) and the next deepest 8/32 tire on the front driver’s side.


If you monitor the tread depths carefully, in about 5000miles, you’ll have a hard time telling which tire is which.

If that skeeves you out, or you don’t want to spend the time monitoring tread depths, then buy two tires, keep the two with the deepest tread depth.

How bad is the pothole flat tire? If there’s a big cut and belt damage or a sidewall blowout, chuck it. But a tire with intact belts from a small tread puncture (like a nail) can be safely patched and be good as new with an internal patch by a competent tire shop - I usually go to my local race tire shop because they don’t try to - a quality internal tire patch can even be safe for competition use. But don’t put up with an external mushroom or or string plug unless you’re just trying to nurse a tire on its last legs until you can buy a new set.

The other option that someone mentioned above is to buy a new tire and have it shaved to depth which any competition tire shop or other well equipped shop can do using the same equipment that they use to shave the tread down on race tires.

If you don’t live near a good shop, apparently Tire Rack can do it for you for $25-35 a tire if you call or email.

https://m.tirerack.com/tires/tiretech/techpage.jsp?techid=259

But honestly at the near new tread depths you’re listing, you probably don’t need to shave (they typically only guarantee within +\-1/32 of target depth
Ah, I totally forgot shaving was an option. I did wind up ordering 2 new Firehawks yesterday and they just got here today. I wish I considered just buying 1 and having tire rack shave it. I’m on the fence as to whether or not I should just install the 2 new ones or return them both and order one that is shaved to 8/32.
 


Dialcaliper

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#12
Ah, I totally forgot shaving was an option. I did wind up ordering 2 new Firehawks yesterday and they just got here today. I wish I considered just buying 1 and having tire rack shave it. I’m on the fence as to whether or not I should just install the 2 new ones or return them both and order one that is shaved to 8/32.
At some point you’re better off installing the two you got and keeping a spare, since you’ll be paying additional shipping costs, which are nuts right now. Not sure what Tire Rack’s return policy is, sending a 15-20lb tire is not going to be cheap if the return is on your dime. I just shipped an oversized 13lb box and Fedex came in the cheapest at $70 for the lowest tier service!
 


M-Sport fan

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#13
At some point you’re better off installing the two you got and keeping a spare, since you’ll be paying additional shipping costs, which are nuts right now. Not sure what Tire Rack’s return policy is, sending a 15-20lb tire is not going to be cheap if the return is on your dime. I just shipped an oversized 13lb box and Fedex came in the cheapest at $70 for the lowest tier service!
^^^THIS!! [wink]
 


OP
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Thread Starter #14
Thank you for all of the replys. One follow-up question:

I know that the standard is to always put the new tires on the back of the car for more stability. Does that apply in this case where my current rear tires have between 6-7/32nds left?

Ideally, I would like to wear the new tires down so they become more in line with the rear. If I throw the new tires on the back, that gap in the tread depths will continue to increase. If I am supposed to throw the new tires in the back, am I still supposed to rotate the tires to the front at some point?
 


SteveS

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#15
The idea with the new tires on the back is supposed to be so that the car doesn't have an oversteer condition, as it's generally assumed that the new tires will have greater traction. That advice also comes from the era when front wheel drive cars were virtually unknown, and the rear tires wore more quickly.

Ever since I started driving FWD cars in the 1970s with my first Fiesta, I've put the new pair on the front for the exact reason you want to.
 


Dialcaliper

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#16
Thank you for all of the replys. One follow-up question:

I know that the standard is to always put the new tires on the back of the car for more stability. Does that apply in this case where my current rear tires have between 6-7/32nds left?

Ideally, I would like to wear the new tires down so they become more in line with the rear. If I throw the new tires on the back, that gap in the tread depths will continue to increase. If I am supposed to throw the new tires in the back, am I still supposed to rotate the tires to the front at some point?
That’s interesting, I’ve always heard the exact opposite, which is always put new tires on the front, for the same reason you put chains on the front (or all 4 in a RWD car), which is that you want traction and steering control.

Tire tread grooves only matter in wet, snow or dirt. They do very little for traction on dry roads, so it doesn’t really matter, with the exception of things like tire noise, tramlining and comfort. The only thing that would affect handling in the dry is if your older tires are heat cycled and have lost some their grip.

If I have to replace two, I always put the new ones on the front because they typically wear faster (especially on FWD and AWD cars). Usually I measure tread depth selectively rotate based on which tire locations wear faster/slower so that I can replace all 4 at the same time

A better rule is simply don’t be foolish and drive in the rain on nearly bald tires.
 


gtx3076

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#17
The idea with the new tires on the back is supposed to be so that the car doesn't have an oversteer condition, as it's generally assumed that the new tires will have greater traction. That advice also comes from the era when front wheel drive cars were virtually unknown, and the rear tires wore more quickly.

Ever since I started driving FWD cars in the 1970s with my first Fiesta, I've put the new pair on the front for the exact reason you want to.
They still recommend new on the rear for oversteer prevention, even on FWD.

To the OP, put the wheel wherever you want. You can always swap it later when it’s more evenly worn.
 


Dialcaliper

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#19
They still recommend new on the rear for oversteer prevention, even on FWD.

To the OP, put the wheel wherever you want. You can always swap it later when it’s more evenly worn.
I can believe that. Funny how everyone gets different recommendations for different reasons! In any case, if you trust your driving, new on the front will net you more even wear and more equal tire properties.

Also, on a FWD nose heavy car, the rear tires do not work nearly as hard, so you’re unlikely to encounter an oversteer condition.

However I could easily see that being a good recommendation for a RWD car, especially if youre doing mostly commuting/city/highway driving (not doing a lot of hard cornering), in which case, your rear tires would tend to wear faster, and also the oversteer issue becomes much more pronounced.
 


gtx3076

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#20
I can believe that. Funny how everyone gets different recommendations for different reasons! In any case, if you trust your driving, new on the front will net you more even wear and more equal tire properties.

Also, on a FWD nose heavy car, the rear tires do not work nearly as hard, so you’re unlikely to encounter an oversteer condition.

However I could easily see that being a good recommendation for a RWD car, especially if youre doing mostly commuting/city/highway driving (not doing a lot of hard cornering), in which case, your rear tires would tend to wear faster, and also the oversteer issue becomes much more pronounced.
The logic is that cars are more likely to lose control on wet/slick roads, even on minor curves at highway speeds.
 




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