Rotating Directional Tires.

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Yesterday I was talking to a trusted mechanic who works only on German cars and does only suspension work and tire installations.

When I told him that I was changing my philosophy about tire rotations, he said that rotations, even though oversold, are not necessarily a bad thing. Some of the things he said were:

- rotate tires every 7,500 miles or so, not more frequently, especially if you are paying someone else do it. If it's done more frequently, your car is never with a "broken in" tires and doesn't handle properly. This, obviously, is about cars that are for performance.

- it's OK to rotate directional tires and have them spin against the direction noted on the sidewall. Both the front and the back can be criss-crossed in a pattern that resembles an X
 
Originally Posted By: CivicFan
Some of the things he said were:

- rotate tires every 7,500 miles or so, not more frequently, especially if you are paying someone else do it. If it's done more frequently, your car is never with a "broken in" tires and doesn't handle properly. This, obviously, is about cars that are for performance.

- it's OK to rotate directional tires and have them spin against the direction noted on the sidewall. Both the front and the back can be criss-crossed in a pattern that resembles an X


I'm not sure I agree with either of those two things. On the first, a tire's break-in period is about the mold releases getting scrubbed off the rubber and the tire going through many heat-cool cycles. The wear pattern on the tire doesn't indicate whether a tire is broken-in or not. I agree that rotating tires is beneficial, but don't agree that it's possible to do it too often.

And I certainly disagree with the second thing he wrote, unless the car is driven strictly on dry pavement. The directional chevrons in a tread pattern are designed to evacuate water out from under the tire's contact patch. That water evacuation ability is utterly removed when you rotate them in the incorrect direction. When a directional tire is rotating backwards, the tread pattern will act to scoop water to the center and under the tire, which is exactly opposite of what you need on wet pavement. When rotating as intended, a good chevron pattern will push water away and forward of the tire. This removes the water from the contact patch.
 
if the manufacturer of my car (mazda) says to rotate every 5K, and the tire place that sold me the tires says I need to rotate every 5K for the warranty to be valid (and they rotate for free) I don't see why I would listen to some guy who 'only works on German cars', like that's something special.
"oohh, he only works on GERMAN cars, he MUST know what he's talking about"

and if someone says you could ignore the directional arrows on the sidewalls of a tire, what else could we ignore?
 
Originally Posted By: sasilverbullet
Nope, you should not run directional tires against the arrow.

This is my understanding as well.
 
Originally Posted By: Hokiefyd
Originally Posted By: CivicFan
Some of the things he said were:

- rotate tires every 7,500 miles or so, not more frequently, especially if you are paying someone else do it. If it's done more frequently, your car is never with a "broken in" tires and doesn't handle properly. This, obviously, is about cars that are for performance.

- it's OK to rotate directional tires and have them spin against the direction noted on the sidewall. Both the front and the back can be criss-crossed in a pattern that resembles an X


I'm not sure I agree with either of those two things. On the first, a tire's break-in period is about the mold releases getting scrubbed off the rubber and the tire going through many heat-cool cycles. The wear pattern on the tire doesn't indicate whether a tire is broken-in or not. I agree that rotating tires is beneficial, but don't agree that it's possible to do it too often.

And I certainly disagree with the second thing he wrote, unless the car is driven strictly on dry pavement. The directional chevrons in a tread pattern are designed to evacuate water out from under the tire's contact patch. That water evacuation ability is utterly removed when you rotate them in the incorrect direction. When a directional tire is rotating backwards, the tread pattern will act to scoop water to the center and under the tire, which is exactly opposite of what you need on wet pavement. When rotating as intended, a good chevron pattern will push water away and forward of the tire. This removes the water from the contact patch.


Very well stated. +1
 
Originally Posted By: CivicFan

- it's OK to rotate directional tires and have them spin against the direction noted on the sidewall. Both the front and the back can be criss-crossed in a pattern that resembles an X


Trusted mechanic? Are you serious?!?
crackmeup2.gif
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You hit a big puddle of water on the freeway with directional tires mounted the wrong way and your car will instantly turn into a 3,000 lb. hockey puck.

The tread design is meant to go one way to evacuate water and grip the road.

Find a new "mechanic" ASAP.
 
I'm surpised that a mechanic who does tire installations would say it is OK to have a tire rotate opposite the direction indicated on the sidewall, for the reasons others have already said.

In general, I think rotating more than every 7500 miles is overkill, with one exception being an all wheel drive system that activates when wheelspin is detected might need more frequent rotations.

Interestingly my neighbor has part time pavement only 4WD system that the owners manual recommends roating every 3500 miles, but he says he's gone twice that with no tire wear or driveline issues in 125K
 
I asked about the water evacuation and his answer was that in wet weather, you should always be careful anyway.

One thing to clarify - I think my initial post was not clear and resulted in this misguided ridicule...

He was not an advocate of running against the direction on the sidewall. He was explaining that IF you want to rotate, and IF you wanted to increase the life of the tread on a BMW like mine, you could do it.
 
Tire Rack tested the theory that directional tires are substantially worse in the rain when run 'backwards'. In a nutshell, as long as the pavement isn't up to the point where some non-directional tires would begin to hydroplane anyway, there's practically no difference in wet traction with respect to rotation direction.
 
I'm not sure that's the conclusion Tire Rack came to. They said:

"...our track challenges the tire tread compound’s ability to provide wet traction more than the tire tread design’s ability to provide hydroplaning resistance."

It is true that without any substantial water evacuation to be done, a backwards directional tire should be on-par with the same one running forwards in terms of generating traction. The issue isn't wet traction, but rather water evacuation. Tire Rack further notes:

"Higher speeds, deeper water or puddles would eventually have increased the differences in wet performance related to how the tires were mounted."
 
Originally Posted By: CivicFan
He was not an advocate of running against the direction on the sidewall. He was explaining that IF you want to rotate, and IF you wanted to increase the life of the tread on a BMW like mine, you could do it.


I think you would agree that your original post indicating that he said that "it's okay" to run directional tires backwards would lead reasonable folks to believe that he sees no downsides to it. I agree with him: it is possible to physically mount them backwards and run them like that. And if your BMW is strictly a sunny-day-only car, then I would see no reason against it.
 
Originally Posted By: Hokiefyd
It is true that without any substantial water evacuation to be done, a backwards directional tire should be on-par with the same one running forwards in terms of generating traction. The issue isn't wet traction, but rather water evacuation.


Yes, and under most wet-weather conditions, no tire should come close to hydroplaning. It's only very heavy rain rates, standing water, etc. (where evacuation becomes the issue) where any tire, directional or otherwise, should start to 'run over' the water.
 
Originally Posted By: CivicFan
Yesterday I was talking to a trusted mechanic who works only on German cars and does only suspension work and tire installations.

When I told him that I was changing my philosophy about tire rotations, he said that rotations, even though oversold, are not necessarily a bad thing. Some of the things he said were:

- rotate tires every 7,500 miles or so, not more frequently, especially if you are paying someone else do it. If it's done more frequently, your car is never with a "broken in" tires and doesn't handle properly. This, obviously, is about cars that are for performance........


On the first item: While he does have a point that it takes some time for a tire to wear to the point where that wear pattern needs to get "undone" by rotating to another position - AND - while he does have a point that you will lose some grip for a while after rotation, I think it is over-stating the interval. Vehicle manufacturers tend to include tire rotation as part of a maintenance schedule that includes quite a few different items for the interval - meaning the interval is somewhat arbitrary.

Tire manufacturers say that in absence of instructions from the vehicle manufacturer, use 5K to 8K as the interval. This seems like a reasonable value - meaning I think he is wrong that you should "wait" for 7.5K. It ought to be a convenient interval.


Originally Posted By: CivicFan
.......
- it's OK to rotate directional tires and have them spin against the direction noted on the sidewall. Both the front and the back can be criss-crossed in a pattern that resembles an X


OK, above this post is a semi-retraction - and the only comment I have to make is an observation:

I hear this type of stuff all the time. Imprecise wording - sometimes even misleading wording. I hope everyone takes a lesson to be careful to say exactly what you mean.

- AND -

Yes, the only property affected by having a directional tire rotate the wrong direction is wet traction. Grip and wear are unaffected.

Originally Posted By: leeharvey418
Tire Rack tested the theory that directional tires are substantially worse in the rain when run 'backwards'. In a nutshell, as long as the pavement isn't up to the point where some non-directional tires would begin to hydroplane anyway, there's practically no difference in wet traction with respect to rotation direction.


I am still of the opinion that Tire Rack's test pad doesn't have enough water depth. When the company I work for brings the Tire Rack folks to the Proving Grounds, we have repeatedly pointed out that we get differences in wet performance that they do not get.

Hokiefyd's post says Tire Rack agrees with that!

But you have to wonder why they bother to report results when they know the results aren't accurate!

- But -

Way back when - the company I work did perform the test and got about a 10% difference in traction. So it's not a lot, but it is there.
 
Last edited:
Originally Posted By: CapriRacer
Yes, the only property affected by having a directional tire rotate the wrong direction is wet traction. Grip and wear are unaffected.


Wet traction or hydroplane resistance?
 
Originally Posted By: CivicFan
Yesterday I was talking to a trusted mechanic who works only on German cars and does only suspension work and tire installations.

When I told him that I was changing my philosophy about tire rotations, he said that rotations, even though oversold, are not necessarily a bad thing. Some of the things he said were:

- rotate tires every 7,500 miles or so, not more frequently, especially if you are paying someone else do it. If it's done more frequently, your car is never with a "broken in" tires and doesn't handle properly. This, obviously, is about cars that are for performance.

- it's OK to rotate directional tires and have them spin against the direction noted on the sidewall. Both the front and the back can be criss-crossed in a pattern that resembles an X


Well, first, I think we need to change the description..."trusted"?

Not anymore...

I am with Capri Racer - the interval is somewhat arbitrary, just synch it up with another maintenance action (every other oil change on a 3,000 mile OCI, or overy oil change on a 7,500 mile OCI for example) and be consistent to maximize the life on non-directional tires.

And for folks (like me) who are concerned with small differences in performance, the idea of giving up 10% of my wet performance by mounting the tires to rotate backwards is crazy...if I am willing to give up 10% of their performance, why did I get them in the first place? Surely there were tires that were non-directional that I could have chosen...and kept full performance over the life of the tires, instead of compromising them half of the time...

You can't claim to be interested in performance, like a "German Car" mechanic...and do something that drastically (and 10% is drastic) degrades it...
 
BMW recommends AGAINST tire rotations as it affects the performance of the car.

I have rotated the tires on the car and I would much rather replace the tires than suffer the consequences of the degraded performance of the car.
 
Originally Posted By: Astro14
Originally Posted By: CivicFan
Yesterday I was talking to a trusted mechanic who works only on German cars and does only suspension work and tire installations.

When I told him that I was changing my philosophy about tire rotations, he said that rotations, even though oversold, are not necessarily a bad thing. Some of the things he said were:

- rotate tires every 7,500 miles or so, not more frequently, especially if you are paying someone else do it. If it's done more frequently, your car is never with a "broken in" tires and doesn't handle properly. This, obviously, is about cars that are for performance.

- it's OK to rotate directional tires and have them spin against the direction noted on the sidewall. Both the front and the back can be criss-crossed in a pattern that resembles an X


Well, first, I think we need to change the description..."trusted"?

Not anymore...

I am with Capri Racer - the interval is somewhat arbitrary, just synch it up with another maintenance action (every other oil change on a 3,000 mile OCI, or overy oil change on a 7,500 mile OCI for example) and be consistent to maximize the life on non-directional tires.

And for folks (like me) who are concerned with small differences in performance, the idea of giving up 10% of my wet performance by mounting the tires to rotate backwards is crazy...if I am willing to give up 10% of their performance, why did I get them in the first place? Surely there were tires that were non-directional that I could have chosen...and kept full performance over the life of the tires, instead of compromising them half of the time...

You can't claim to be interested in performance, like a "German Car" mechanic...and do something that drastically (and 10% is drastic) degrades it...


His whole point was about your concern - people have been scared into thinking that the car will blow up if the directional tires are mounted the opposite way. But if you read the TireRack article, you will see that there was no compromise in safety.
 
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