Tire Rotation Pattern Theory -- Why?

[Carbon]

Many tire sites suggest something called the "forward cross" for rotating tires in front-wheel drive vehicles, and the "rearward cross" for RWD or 4WD vehicles.
Forward and rearward cross search I have tried to find out why and maybe where the original suggestion came from. I think it has just become conventional wisdom.

Tire Rack is one of several sites that has the same terms and advice. http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=43 Their 5-wheel rotation picture is shown here, but the same patterns without the spare are in that site.

It is not clear to me why one pattern is considered better for FWD and the other is better for RWD and 4WD. I don't think it is a big deal which way you do it, but I sure wonder about the underlying thinking. Any theories?

 

[Tornado Red]

I don't think it matters which way you rotate. You just want to make sure you're doing it the same way every time. So if you have a FWD car and use the forward cross including the spare one time, just do it the same way the next time. Knowing that one method is recommended for FWD cars and the other for RWD might help you remember to do it the same each time.

 

[CharlieJ]

I do not have a full size spare tire so I have used method "A" for the mazda3.

 

[Johnny248]

It is good to switch the direction of the tire so you start wearing the tires in the other direction. Many times tires start to get choppy or feather (like the way a circular saw blade spins the with the teeth doing the digging into the wood) Tires tend to start to do that. Once they get back enough it starts getting noisy because it is no longer a smooth rotation. So by switching the direction of the tire it starts to wear the opposite direction and keeps the tire as "Round" as can be

 

[Eddie]

Simple answer to to equalize wear. Same philosophy why you never find a gear set at a 1:1 ratio at least for heavy loaded gears like an a transmission or differential

 

[donz26]

The factory service manuals for both my Maxima and Frontier recommend the tire rotation pattern back to front(no side to side crossing).
I have done the "rearward cross" on the truck. I don't think the pattern matters so much as long as the tires get rotated.

 

[Tornado Red]

Originally Posted By: donz26
The factory service manuals for both my Maxima and Frontier recommend the tire rotation pattern back to front(no side to side crossing).
I have done the "rearward cross" on the truck. I don't think the pattern matters so much as long as the tires get rotated.


Did those vehicles originally come with directional tires? If so then you can only do front/back rotations.

But if you've switched to non-directional replacement tires, then you are free to rotate side to side.

 

[Lorenzo]

Many cars come with several optional tires, some directional and some not. So if there is a possibility of directional tires it's safer to recommend non-crossed rotation than have a bonehead put directionals on backwards and sue them.

 

[Maritime Storm]

You'll find that the rotation recommendations are now front to back. There are two reasons for this; 1. changing tires from side to side actualy decreases the life of the tire because of the way tires wear(saw tooth pattern), it does wear the tires evenly but faster and 2. more vehicle are being produced with directional tires.

 

[CapriRacer]

First: The most important thing is for you to rotate your tires. Each position on a vehicle has its own unique wear pattern. Staying too long in one positiion will end up with some part of the tire wearing faster - and that means the tire has be replaced prematurely. Rotation also prevents irregular wear getting too far along that the tire makes noise and vibrates and has to be removed before it is completely worn out.

Of secondary importance is the pattern. In the early days of radial tires, they recommended rotation patterns only front to back. That was because sometimes the bonding between the steel and the rubber would allow a small spearation on one side of the steel wire, and changing the direction of rotation caused the separation on the other side. That is no longer true.

Modern radial tires can - and should - be cross rotated. The theory behind the FWD / RWD difference is that when a tire comes off a drive position, it will have a little heel and toe wear. This type of wear can be noisy if the direction of travel is reversed. Keeping the tire on the same side will cause the heel and toe wear to gradually wear away, so that when it is cross rotated, the wear pattern will not cause a noise - or at least minimize it.

 

[Papa Bear]

Thanks, Capri, for clearing that up for us. I will rotate according to my manual in confidence.

 

[Quattro Pete]

And of course if you have directional tires, all you can do is front-to-back, regardless if it's FWD, RWD, or AWD. And then there is BMW which advises against tire rotation altogether...

 

[Carbon]

Originally Posted By: CapriRacer
The theory behind the FWD / RWD difference is that when a tire comes off a drive position, it will have a little heel and toe wear. This type of wear can be noisy if the direction of travel is reversed. Keeping the tire on the same side will cause the heel and toe wear to gradually wear away, so that when it is cross rotated, the wear pattern will not cause a noise - or at least minimize it.


Thanks! I could find nothing that offered any insight as to where this FWD / RWD pattern difference came from.

 

[mechtech2]

Front wheel drive cars have a tendency to wear the outside of the front tire's edge a bit more.
So cross rotating them is supposed to help with evening out wear, in the long run.
So much for theory.
Why not simply front to back? I dunno. With many directional ties you HAVE to rotate front to back.

 

[froggy81500]

Originally Posted By: mechtech2
Front wheel drive cars have a tendency to wear the outside of the front tire's edge a bit more.
So cross rotating them is supposed to help with evening out wear, in the long run.
So much for theory.
Why not simply front to back? I dunno. With many directional ties you HAVE to rotate front to back.


Front to back doesn't take into account any wear patterns caused by road crown. Some roads have more crown than others for draining. Around here typically the peak is down the center, where the right lane rolls off to the right, left to left. So you end up with a slight pull down in the direction of the crown and it will cause wear different from side to side. For that reason, I don't like to get directional tires because I would much rather cross rotate them to get longevity.

 

[Hokiefyd]

Originally Posted By: Carbon
Originally Posted By: CapriRacer
The theory behind the FWD / RWD difference is that when a tire comes off a drive position, it will have a little heel and toe wear. This type of wear can be noisy if the direction of travel is reversed. Keeping the tire on the same side will cause the heel and toe wear to gradually wear away, so that when it is cross rotated, the wear pattern will not cause a noise - or at least minimize it.


Thanks! I could find nothing that offered any insight as to where this FWD / RWD pattern difference came from.


Ditto, I've always wondered what the difference is, as I always thought that whether you crossed the front to the back or the back to the front, in the end, they all get rotated anyway, so why the distinction? Now we know. Thanks again!

 

[Hokiefyd]

Originally Posted By: froggy81500
For that reason, I don't like to get directional tires because I would much rather cross rotate them to get longevity.


And I as well. There are some excellent uni-directional tires (like the Goodyear Assurance TripleTred), but there are also enough excellent alternatives that I can always find a reason to pick another good, and non-directional, choice.

 

[froggy81500]

FWD and RWD don't always rotate different patterns.

For instance. I've got a Saturn Ion that specs rear cross rotation, where the front tires get crossed to opposite sides in the rear. My wife on the other hand has an 08 Sportage 2wd (FWD) and it is the exact opposite. It specs for a foward cross pattern so the tires coming from the back go on opposite sides to the front.

 

[Hokiefyd]

My '07 Chrysler T&C (FWD) calls for the fronts to go straight back, and for the rears to cross to the front. My '97 Dakota (RWD) calls for the opposite: for the rears to move up and for the fronts to cross to the back.

My '07 Corolla (FWD), for some reason, does not recommend a cross pattern, and recommends simple front-to-back rotations. I do the typical FWD cross pattern anyway (fronts straight back, rears cross forward).

 

[tomcat27]

In automotive school, our instructor explained it similarly to what CapriRacer said, although not so much wearing away the tread but rather allowing the belts to "relax" before switching sides.

So, the driven wheels always stay on the same side, and the non-driven wheels should be criss-crossed.