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Old 03-04-2021, 11:46 PM   #1
Golconda
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Lightbulb Do I really need to rotate my tires that often?

I am wondering if I am going about this the right way. For the most part, my tires wear evenly from left to right (or symmetrically), but the fronts wear faster than the rear.

Both the tire shop and the dealer recommend I have my tires (or actually the tire & wheel assembly) rotated every 5k to 6k miles. If the tires wear evenly left to right and the only useful rotation would be front to back, there seems to be no sense in rotating them more than once in the lifetime of the tires.

I have asked numerous tire shops and dealers why one needs to rotate their evenly wearing tires every 5k to 6k miles, and I have yet to encounter a single one which can give me a good answer.

Here is my reasoning: For example, if you get the tires with 11/32" tread on them and need to replace them at 3/32" tread, you have 8/32" life on them. Let's say at 15,000 miles, you have burned 5/32" off the front and are now at 6/32" and you have burned 3/32" off the rear and are at 8/32". That is the 50% wear point of the tires, and you can rotate them then. After which, the tires now on the front will catch up to the rear and all four tires will need to be replaced at the same time.
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Old 03-06-2021, 09:20 AM   #2
ag565656
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You need to rotate them more often. Here are a few bullet points:

1. You have an AWD system and you don't want too big of a difference between tread depths. That can cause more strain on the differentials.

2. If you wait till 3/32nds, half of your tires are just worthless in anything other than dry conditions. You get some rain or anything and they're at risk of not being able to displace the elements. Remember tread depth isn't just about running out of rubber, it's also about providing channels for water to flow.

3. The rotation, like a lot of maintenance, is also a good chance to thoroughly inspect the wheels, tires, some of the visible suspension components, the brake rotors, etc. This should be viewed as an opportunity than anything else.

I hope that helps a bit.
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Old 03-06-2021, 11:12 AM   #3
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Originally Posted by ag565656 View Post
You need to rotate them more often. Here are a few bullet points:

1. You have an AWD system and you don't want too big of a difference between tread depths. That can cause more strain on the differentials.
My understanding, and what the dealer has said is a delta of 4/32" or 5/32" between the front and rear will have no detrimental impact on the differential. Here is an interesting discussion on this. https://mechanics.stackexchange.com/...-4-wheel-drive. Why would it be as little as 2/32" on a Subaru, but quite a bit more - like 4/32" - on other AWDs?

Quote:
2. If you wait till 3/32nds, half of your tires are just worthless in anything other than dry conditions. You get some rain or anything and they're at risk of not being able to displace the elements. Remember tread depth isn't just about running out of rubber, it's also about providing channels for water to flow.
Agreed. I was using 11/32" to 3/32" as an illustration only. I could use 10/32" to 4/32" if that would make you happy - and when the fronts get to 6/32" (or 66.7% of wear), while the rears are are 8/32" (or 33.3% of wear), you do your single rotation then.

Quote:
3. The rotation, like a lot of maintenance, is also a good chance to thoroughly inspect the wheels, tires, some of the visible suspension components, the brake rotors, etc. This should be viewed as an opportunity than anything else.
Agreed. But if the case, then the rotation follows the inspection. IOW, you should inspect those components every 5k to 6k miles and as long as you have your tires off, you might as well rotate the tires. Not you should rotate the tires every 5k to 6k and as long as you have the tires off, it is an opportunity to inspect those components.

Last edited by Golconda; 03-06-2021 at 11:26 AM.
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Old 03-06-2021, 02:32 PM   #4
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I would think the technical details of the differentials is a little bit more complex, because Subaru has a few different designs they use in the lineup and it's certainly different than a 4WD description. Remember that Subaru is one of the more affordable "real AWD" systems available - there's a big price gap between the other cars with such systems that you'll find in Audi and other high end brands. This price gap means Subaru has to work around the budget and so that is why it could be different than other brands. If you read the manual, I believe some Subarus aren't even supposed to have the spare on the front, but rather the rear. I think older Subarus can have the rear wheels disconnected from power delivery by pulling a fuse to accommodate spare tire situations.

As someone who is spending so much time looking into this, you also probably care about the quality of your drive and optimal performance characteristics. Wouldn't you want to get even wear for that reason alone? A tire rotation doesn't cost much in the way of money or time anyway. Depending on where you get your tires, lifetime rotate/balance is included anyway. I know I get that benefit at Costco.

This is pretty far down the list of things that are really worth discussing/debating in my opinion. I think some cars say you can change the oil filter every other oil change... but for such a cheap and critical part, why would anyone bother?

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Originally Posted by Golconda View Post
My understanding, and what the dealer has said is a delta of 4/32" or 5/32" between the front and rear will have no detrimental impact on the differential. Here is an interesting discussion on this. https://mechanics.stackexchange.com/...-4-wheel-drive. Why would it be as little as 2/32" on a Subaru, but quite a bit more - like 4/32" - on other AWDs?


Agreed. I was using 11/32" to 3/32" as an illustration only. I could use 10/32" to 4/32" if that would make you happy - and when the fronts get to 6/32" (or 66.7% of wear), while the rears are are 8/32" (or 33.3% of wear), you do your single rotation then.


Agreed. But if the case, then the rotation follows the inspection. IOW, you should inspect those components every 5k to 6k miles and as long as you have your tires off, you might as well rotate the tires. Not you should rotate the tires every 5k to 6k and as long as you have the tires off, it is an opportunity to inspect those components.
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Old 03-07-2021, 01:03 AM   #5
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I would think the technical details of the differentials is a little bit more complex, because Subaru has a few different designs they use in the lineup and it's certainly different than a 4WD description. Remember that Subaru is one of the more affordable "real AWD" systems available - there's a big price gap between the other cars with such systems that you'll find in Audi and other high end brands. This price gap means Subaru has to work around the budget and so that is why it could be different than other brands. If you read the manual, I believe some Subarus aren't even supposed to have the spare on the front, but rather the rear. I think older Subarus can have the rear wheels disconnected from power delivery by pulling a fuse to accommodate spare tire situations.
That may help explain why it is 2/32" max delta on a Subaru and 4/32" max delta on other AWD vehicles.

Quote:
As someone who is spending so much time looking into this, you also probably care about the quality of your drive and optimal performance characteristics. Wouldn't you want to get even wear for that reason alone? A tire rotation doesn't cost much in the way of money or time anyway. Depending on where you get your tires, lifetime rotate/balance is included anyway. I know I get that benefit at Costco.
Yes, it is free at the place I buy my tires. But unless there is a good reason to rotate my tires more than once in the lifetime of my tires, it is not worth the extra time to have these additional rotations. And I have yet to encounter a good reason.

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This is pretty far down the list of things that are really worth discussing/debating in my opinion. I think some cars say you can change the oil filter every other oil change... but for such a cheap and critical part, why would anyone bother?
Not a fair comparison, as you are already in the shop to have the oil changed. Any time I am already in the shop for some kind of tire work, then it likely is a no-brainer to have the tires rotated.
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Old 03-07-2021, 11:17 AM   #6
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Default Do I really need to rotate my tires that often?

If you are only getting 15,000 miles out of tires then your driving habits should change asap. I drive a lot and hard and I run through tires about once a year. I rotate my tires every oil change and balance them every other oil change. Granted I work in a shop and I follow the same practice/method I recommend, your rear tires just roll essentially. Rotating them allows for more uniform wear.

Edit: I do oil changes around 4500/5000 miles and average about 30,000 miles a year.
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Old 03-07-2021, 12:15 PM   #7
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Short answer is yes, you should do it every 5K as a general rule of thumb for all real AWD (Not so much with 4WD) systems. The interval and the tolerance are as much as for the preservation of the more sophisticated AWD system as it is about prolonging the life of the tires.

As for the Subaru, it depends on which model you have as Subaru also uses different types of AWD systems through out their lineup. Without going into details, because it is a lot and you can look them up and study them on your own, even a few videos on YouTube and here are two to get you started:



Basically, the more sophisticate the AWD system is, the more sensitive they are and their tolerance will be lower. Systems such as the ones on the STI (DCCD), Torsen based Audi Quattro and Nissan's ATTESA E-TS.

With that being said, since you find something as simple as tire rotation not worth your time, you can do whatever you want with your car. Just take full responsibility of this decision should you do encounter issues in the future.
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Old 03-07-2021, 12:44 PM   #8
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Originally Posted by TifosiWA View Post
Short answer is yes, you should do it every 5K as a general rule of thumb for all real AWD (Not so much with 4WD) systems. The interval and the tolerance are as much as for the preservation of the more sophisticated AWD system as it is about prolonging the life of the tires.

As for the Subaru, it depends on which model you have as Subaru also uses different types of AWD systems through out their lineup. Without going into details, because it is a lot and you can look them up and study them on your own, even a few videos on YouTube and here are two to get you started:

https://www.youtube.com/watch?v=WBQlK89PyxQ

https://www.youtube.com/watch?v=YIY392Qtu0I

Basically, the more sophisticate the AWD system is, the more sensitive they are and their tolerance will be lower. Systems such as the ones on the STI (DCCD), Torsen based Audi Quattro and Nissan's ATTESA E-TS.

With that being said, since you find something as simple as tire rotation not worth your time, you can do whatever you want with your car. Just take full responsibility of this decision should you do encounter issues in the future.
Much of what I find on the internet says the delta should not be greater than 2/32". So let's say my tires come with 10/32" and I plan to replace them at 4/32". Let's say the fronts wear twice as fast as the rears and at 15,000 miles are at 6/32", while the rears are at 8/32". At that point I rotate them. Then the fronts - which are now at 8/32" catch up with the rears when they all reach 4/32" at around 30,000 miles. So unless the fronts wear MORE than twice as fast as the rears, there would be no good reason to rotate them more than once during the lifetime of the tires.

Tire rotation is not quite as simple as it may seem. It is not like Jiffy Lube where you can drive up when you want and get them rotated within an hour.
Most tire shops require you to make an appointment and leave the car there for as much as 3x or 4x the actual amount of time it takes to rotate the tires.
But a good reason to rotate the tires more often would negate that inconvenience, and I'd do it.
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Old 03-07-2021, 12:52 PM   #9
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If you are only getting 15,000 miles out of tires then your driving habits should change asap. I drive a lot and hard and I run through tires about once a year. I rotate my tires every oil change and balance them every other oil change. Granted I work in a shop and I follow the same practice/method I recommend, your rear tires just roll essentially. Rotating them allows for more uniform wear.

Edit: I do oil changes around 4500/5000 miles and average about 30,000 miles a year.
I also get around 30k miles out of my tires, and I rotate them only once during the lifetime of the tires. Going from 10/32" to 4/32", unless the fronts wear more than twice the rate of the rears, I'll never exceed a 2/32" delta between the front and the rear. I do not see how extra rotations would help me get more life out of the tires.
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Old 03-07-2021, 04:13 PM   #10
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Originally Posted by Golconda View Post
Much of what I find on the internet says the delta should not be greater than 2/32". So let's say my tires come with 10/32" and I plan to replace them at 4/32". Let's say the fronts wear twice as fast as the rears and at 15,000 miles are at 6/32", while the rears are at 8/32". At that point I rotate them. Then the fronts - which are now at 8/32" catch up with the rears when they all reach 4/32" at around 30,000 miles. So unless the fronts wear MORE than twice as fast as the rears, there would be no good reason to rotate them more than once during the lifetime of the tires.

Tire rotation is not quite as simple as it may seem. It is not like Jiffy Lube where you can drive up when you want and get them rotated within an hour.
Most tire shops require you to make an appointment and leave the car there for as much as 3x or 4x the actual amount of time it takes to rotate the tires.
But a good reason to rotate the tires more often would negate that inconvenience, and I'd do it.
You are stuck on the theoretical part and not real life situation. And again, there are different types of "AWD" system out there so the tire wear pattern will differ. In addition, front tires and rear tires will always wear differently and if one were to show wear twice as fast as the other on a true AWD vehicle, you have other issues that is going on, including the driver as a potential issue. And you pretty much answered your own question there, as the whole point of rotating your tires every 5K is to prevent the tires to wear unevenly in a way that will result in more than 2/32" differences between the front and the rear.

Now onto your issue about the actual rotation. Do you work on your own car or do you depend on dealership/shop to do that? If you work on your own car, it is really surprising that you are complaining about tire rotation because it is part of the regular maintenance for anyone that works on their own cars. If you have someone else to it for you, then you have them rotate the tires at the same time while they are working on the car. I don't know your back story but where I am at, it is not impossible to just do a walk-in at a tire shop and be out within an hour most of the time.

Now finally, seeing that you joined this forum back in July of 2014, it is even harder to believe that any of this is new to you. Anyway, ultimately, it is up to you. If you don't feel that you have an adequate reason to do it every 5K, then don't.
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Old 03-07-2021, 05:02 PM   #11
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Where are these magical 10 and 12/32 tires? My last 2 sets of tires started off new around 8/32
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Old 03-08-2021, 12:21 AM   #12
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You are stuck on the theoretical part and not real life situation. And again, there are different types of "AWD" system out there so the tire wear pattern will differ. In addition, front tires and rear tires will always wear differently and if one were to show wear twice as fast as the other on a true AWD vehicle you have other issues that is going on, including the driver as a potential issue.
As I said, the fronts would have to wear twice as fast as the rear (a highly unlikely occurrence) for the delta to become as great as 2/32" if the tires are rotated once in the lifetime of the tires (assuming the tires start at 10/32" and finish at 4/32").

The whole idea is to ensure that if you are strictly doing front to rear rotation, then each tire should be on the front of the vehicle 50% of the time during the life of the tires and on the rear of the vehicle 50% of the time during the life of the tires. To achieve this, it does not require a rotation every 5,000 miles - unless your tires only last 10,000 miles. If your tires last 30,000 miles, this can be achieved with a single rotation at 15,000 miles, saving the owner a considerable amount of time and in some cases money.


Quote:
And you pretty much answered your own question there, as the whole point of rotating your tires every 5K is to prevent the tires to wear unevenly in a way that will result in more than 2/32" differences between the front and the rear.
Why would you need to rotate them every 5K to prevent more than a 2/32" difference between the front and rear? As you said - and I agree with you - if you do, then the driver/owner has other issues going on.

Quote:
Now onto your issue about the actual rotation. Do you work on your own car or do you depend on dealership/shop to do that? If you work on your own car, it is really surprising that you are complaining about tire rotation because it is part of the regular maintenance for anyone that works on their own cars. If you have someone else to it for you, then you have them rotate the tires at the same time while they are working on the car. I don't know your back story but where I am at, it is not impossible to just do a walk-in at a tire shop and be out within an hour most of the time.
I don't do periodic maintenance on my car myself - I take it to a shop. The place I buy my tires at does not permit walk-ins for tire rotation. Thus it is more time consuming than you may think.

Quote:
Now finally, seeing that you joined this forum back in July of 2014, it is even harder to believe that any of this is new to you. Anyway, ultimately, it is up to you. If you don't feel that you have an adequate reason to do it every 5K, then don't.
It is not new to me. My philosophy has always been to have each tire on the front 50% of the time and the rear 50% of the time via the least # of rotations necessary to achieve that.
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Old 03-08-2021, 12:29 AM   #13
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if you dont do your own maintenance, dont sweat it, and just pay the man.
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Old 03-08-2021, 01:12 AM   #14
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As I said, the fronts would have to wear twice as fast as the rear (a highly unlikely occurrence) for the delta to become as great as 2/32" if the tires are rotated once in the lifetime of the tires (assuming the tires start at 10/32" and finish at 4/32").

The whole idea is to ensure that if you are strictly doing front to rear rotation, then each tire should be on the front of the vehicle 50% of the time during the life of the tires and on the rear of the vehicle 50% of the time during the life of the tires. To achieve this, it does not require a rotation every 5,000 miles - unless your tires only last 10,000 miles. If your tires last 30,000 miles, this can be achieved with a single rotation at 15,000 miles, saving the owner a considerable amount of time and in some cases money.
You do realize that as physics would have it, your front tires will not wear evenly across right? The outer shoulder will have more wear than the center and the inner portion of the tire. Again you are stuck in one dimensional thinking when you need to step back and look at it as a whole. Tire rotation are needed to not only to even out wear between all 4 tires but also for each individual tire, this is especially important when it comes to unidirectional tires.


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if you dont do your own maintenance, dont sweat it, and just pay the man.
The OP already stated it before that his time is too valuable to have someone else do it for him.
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Old 03-08-2021, 02:09 AM   #15
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You do realize that as physics would have it, your front tires will not wear evenly across right? The outer shoulder will have more wear than the center and the inner portion of the tire. Again you are stuck in one dimensional thinking when you need to step back and look at it as a whole. Tire rotation are needed to not only to even out wear between all 4 tires but also for each individual tire, this is especially important when it comes to unidirectional tires.
If doing front to rear rotation, then one rotation in the lifetime of the tires is IMO sufficient (this way each set is on the rear 50% and the front 50%). If doing a partial X rotation, then three rotations in the life of the tires is sufficient. In the latter case, if the tires are expected to last 30k, then one rotation every 7.5k is sufficient, meaning each tire is in each location for 1/4 of the life of the tires.

I disagree with the double X rotation, as it would not allow for each tire to be in each location 1/4 of the time.


Quote:
The OP already stated it before that his time is too valuable to have someone else do it for him.
I do have the tire shop do rotations for me, as it is free with the purchase of my tires. But I would actually rather pay a small fee to have a shop do it on a drop-in basis rather than get it for free at the shop where I bought the tires, as they require me to make an appointment and need to keep the car for two or three times the actual time it takes to rotate the tires.
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Old 03-08-2021, 10:07 AM   #16
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you just cant make this stuff up. LOL
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Old 03-08-2021, 10:43 AM   #17
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If doing front to rear rotation, then one rotation in the lifetime of the tires is IMO sufficient (this way each set is on the rear 50% and the front 50%). If doing a partial X rotation, then three rotations in the life of the tires is sufficient. In the latter case, if the tires are expected to last 30k, then one rotation every 7.5k is sufficient, meaning each tire is in each location for 1/4 of the life of the tires.
Let try this one last time. You are convoluting things together and this is why you are having difficulties with this.

1) Tire rotation is needed to even out tire wear of all four tires and most importantly, to each individual tires as stated above already. If you do this, you SHOULD not find yourself in a situation that will result in a delta in thread depth of greater than 2/32" between any of them. If you do, then there is a bigger issue for you to worry about.

2) The delta of 2/32" has more to do and is more of a guideline when it comes to replacing tires under abnormal circumstances such as unrepairable puncture, blow out, delamination etc. Basically, when less than 4 tires needs to be replaced. This has more to do with saving the vehicle's differentials.

The two points are both related in theory, which is where you are stuck in, and unrelated, which is where the reality is in most cases, all at the same time. IF, you are able to keep your tire wear evenly within itself for say, in your case of 15K+ miles, then rotation is not necessary. In this case, all you have to worry about is the 2/32" delta between the tires when it happens. Another scenario this can occur is when you have a car with staggered setup and rotation is not possible.
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Old 03-08-2021, 04:32 PM   #18
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IF, you are able to keep your tire wear evenly within itself for say, in your case of 15K+ miles, then rotation is not necessary. In this case, all you have to worry about is the 2/32" delta between the tires when it happens. Another scenario this can occur is when you have a car with staggered setup and rotation is not possible.
It seems you and I are in agreement. As I said earlier, in a situation where the tires go from 10/32" (new) to 4/32" (replace), the fronts would have to wear at minimum twice as fast as the rear for a delta of 2/32" to be achieved at 50% of the lifetime of the tires. And I agree with you that if the fronts are wearing at more than double the rate of the rears, there are other things to be concerned with.
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Old 03-08-2021, 09:11 PM   #19
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It seems you and I are in agreement. As I said earlier, in a situation where the tires go from 10/32" (new) to 4/32" (replace), the fronts would have to wear at minimum twice as fast as the rear for a delta of 2/32" to be achieved at 50% of the lifetime of the tires. And I agree with you that if the fronts are wearing at more than double the rate of the rears, there are other things to be concerned with.
Nothing personal, but unless I live in a theoretical world, we are not even close on agreeing when it comes to this topic. Again, for whatever reason, you have a real myopic view when it comes to tire thread wears and continues to be stuck on the thread depth and thread depth only. When you measure thread wear, you don't just measure in one spot, you measure it across the entire thread of the tire.

Since I live and drive in a world that has turns and the have the need to brake and slow down, my tires will never wear evenly across so I will continue to follow the 5K miles tire rotation schedule.

Happy motoring and stay safe.

Last edited by TifosiWA; 03-08-2021 at 11:43 PM.
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Old 03-09-2021, 10:56 AM   #20
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Originally Posted by Golconda View Post
As I said, the fronts would have to wear twice as fast as the rear (a highly unlikely occurrence) for the delta to become as great as 2/32" if the tires are rotated once in the lifetime of the tires (assuming the tires start at 10/32" and finish at 4/32").

The whole idea is to ensure that if you are strictly doing front to rear rotation, then each tire should be on the front of the vehicle 50% of the time during the life of the tires and on the rear of the vehicle 50% of the time during the life of the tires. To achieve this, it does not require a rotation every 5,000 miles - unless your tires only last 10,000 miles. If your tires last 30,000 miles, this can be achieved with a single rotation at 15,000 miles, saving the owner a considerable amount of time and in some cases money.
I'm not seeing any good reason for letting the tires get all the way out to 2/32" difference in tread depth. That's a max-difference setting, meaning that working to a 1/32" difference ought to be better for everything concerned. Not having the center diff bits constantly rotating to accommodate bigger differences in front vs rear wheel rpms in particular.


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I don't do periodic maintenance on my car myself - I take it to a shop. The place I buy my tires at does not permit walk-ins for tire rotation. Thus it is more time consuming than you may think.
If you can't or won't do your own tire rotation, or you're unwilling to wait for somebody else to do it for you, or pay for more than one rotation per set of tires . . . you may be painting yourself into a corner that has no solution that's acceptable to you. That's what happens when you put up too many restrictions.

Maybe you need to find a different tire shop that will accommodate walk-in tire rotation business. Or get a relative or acquaintance to do the rotations in exchange for something of value to them (case of beer, gift card, etc.).


Obviously you don't get cold enough winters to need different tires for the colder months. At least I hope that's the case, otherwise you'd have two easy tire rotations every year.



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Old 03-09-2021, 11:19 AM   #21
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I can't say I've ever noticed any tread depth difference F/R on either of my cars with any of the tires I've had. I do get uneven wear due to camber on my autox car, but my daily, the most I see is a bit of rounding of the tread shoulders on the front tires (be it summer or winter sets.) Like Norm said, easy rotations twice a year switching between sets, just put the more square set on front.

I'd have to suspect bad alignment or worn front end parts if the fronts were consistently wearing faster.


EDIT: It should be mentioned that the Subaru center differential in most cases is a viscous coupling, and constant rotation of the viscous coupling due to different diameter tires can overheat it and cause it to fail. This is the reason you NEED to rotate more frequently to keep tread depths equal. If you can't afford the time to rotate tires, you really won't like the time it takes to open up the transmission and replace the coupling.

Last edited by T-37; 03-09-2021 at 12:03 PM.
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Old 03-19-2021, 12:18 PM   #22
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Nothing personal, but unless I live in a theoretical world, we are not even close on agreeing when it comes to this topic. Again, for whatever reason, you have a real myopic view when it comes to tire thread wears and continues to be stuck on the thread depth and thread depth only. When you measure thread wear, you don't just measure in one spot, you measure it across the entire thread of the tire.

Since I live and drive in a world that has turns and the have the need to brake and slow down, my tires will never wear evenly across so I will continue to follow the 5K miles tire rotation schedule.

Happy motoring and stay safe.
Would you agree that with reversible tires, each tire should be on each wheel for 1/4 of the life of the tires - regardless of how often they are rotated? And same for non-reversible tires - that each tire should be on the front for 1/2 of the life and on the rear for 1/2 of the life?

And I should add that if I rotate my tires just three times in the life of the tires such that each tire is in each location 1/4 of the life of the tires, I will get more life than you will by rotating yours every 5,000 miles - unless the tires last for precisely an amount of miles which is divisible by 20,000. Here is why. Let's say the tires will last 30,000. To get each tire on each location 1/4 of the life, I rotate every 7,500 miles. You rotate every 5,000 miles. After 20k, each of your tires will have been in each location 1/4 of the time, but you have 10k to go. During that last 10k, you continue your rotations every 5k miles. What you end up with is each tire being in two spots for 10k and the other two spots for 5k, while I get each tire in each spot for 7.5k. Be honest with yourself and ask which of those two is better for the tires?

Last edited by Golconda; 03-19-2021 at 02:59 PM.
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Old 03-19-2021, 12:48 PM   #23
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Originally Posted by Norm Peterson View Post
I'm not seeing any good reason for letting the tires get all the way out to 2/32" difference in tread depth. That's a max-difference setting, meaning that working to a 1/32" difference ought to be better for everything concerned. Not having the center diff bits constantly rotating to accommodate bigger differences in front vs rear wheel rpms in particular.
In the example of the tire which has a life of 10/32" to 4/32", to achieve a delta of 2/32" prior to the tires being at 50% of their life, the fronts would have to wear at least twice the rate of the rears. And as someone eloquently pointed out earlier in this thread, if the fronts and rears are wearing at that much of a different rate, it is a sign of an altogether separate problem.

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If you can't or won't do your own tire rotation, or you're unwilling to wait for somebody else to do it for you, or pay for more than one rotation per set of tires . . . you may be painting yourself into a corner that has no solution that's acceptable to you. That's what happens when you put up too many restrictions.
No matter how you twist it, tire rotation costs time and sometimes money. This is why I limit the number of rotations to enough so each tire sits on the front for 50% and on the rear for 50% of the life of the tires (or if using reversible tires each tire sits on each wheel for 25% of the life of the tires)

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Maybe you need to find a different tire shop that will accommodate walk-in tire rotation business. Or get a relative or acquaintance to do the rotations in exchange for something of value to them (case of beer, gift card, etc.).
Very good point and worthy of a separate discussion. The bigger tire shops offer free rotations, balance and flat repairs over the life of the tires, but to avoid having to pay that cost, they can make it cost you too much of your time such that it makes more sense to have a mom & pop shop do the rotation for a small fee.

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Obviously you don't get cold enough winters to need different tires for the colder months. At least I hope that's the case, otherwise you'd have two easy tire rotations every year.
Correct. I live in an area where the roads never freeze and seldom to never does it snow.
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Old 03-19-2021, 12:52 PM   #24
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Originally Posted by T-37 View Post
I can't say I've ever noticed any tread depth difference F/R on either of my cars with any of the tires I've had. I do get uneven wear due to camber on my autox car, but my daily, the most I see is a bit of rounding of the tread shoulders on the front tires (be it summer or winter sets.) Like Norm said, easy rotations twice a year switching between sets, just put the more square set on front.

I'd have to suspect bad alignment or worn front end parts if the fronts were consistently wearing faster.


EDIT: It should be mentioned that the Subaru center differential in most cases is a viscous coupling, and constant rotation of the viscous coupling due to different diameter tires can overheat it and cause it to fail. This is the reason you NEED to rotate more frequently to keep tread depths equal. If you can't afford the time to rotate tires, you really won't like the time it takes to open up the transmission and replace the coupling.
As stated earlier, Subaru says the delta should always remain no greater than 2/32". With tires which go from 10/32" to 4/32', this would mean the fronts would have to wear at least twice the rate of the rears to achieve a delta of 2/32" by the 50% wear mark of the tires. And if such a difference in wear did occur, it would be the sign of an altogether different problem which would need to be addressed. So I rotate my tires only as frequently as necessary to see each tire is on the front 50% of the life and on the rear 50% of the life.
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Old 03-20-2021, 02:25 AM   #25
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Originally Posted by Golconda View Post
Would you agree that with reversible tires, each tire should be on each wheel for 1/4 of the life of the tires - regardless of how often they are rotated? And same for non-reversible tires - that each tire should be on the front for 1/2 of the life and on the rear for 1/2 of the life?

And I should add that if I rotate my tires just three times in the life of the tires such that each tire is in each location 1/4 of the life of the tires, I will get more life than you will by rotating yours every 5,000 miles - unless the tires last for precisely an amount of miles which is divisible by 20,000. Here is why. Let's say the tires will last 30,000. To get each tire on each location 1/4 of the life, I rotate every 7,500 miles. You rotate every 5,000 miles. After 20k, each of your tires will have been in each location 1/4 of the time, but you have 10k to go. During that last 10k, you continue your rotations every 5k miles. What you end up with is each tire being in two spots for 10k and the other two spots for 5k, while I get each tire in each spot for 7.5k. Be honest with yourself and ask which of those two is better for the tires?
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