So more snow/ice in MD coming, and salt on the roads, so my 2010 XK sits in the garage with a CTEK. Sigh. I've got Michelin Pilot Sport A/S 3 on Ruby (claret color). The tires are not directional, they have 'outside' marked on the side wall. Obviously, can't rotate front to back, but I could rotate side to side. Is that beneficial for evening out tire wear and prolonging the life of the tires? Does anyone rotate their tires side to side?

If nothing else, it lets me look at the condition of brakes and suspension parts. Ruby needs some attention!

Best,
~wrair

 

Guess I am challenged in 3-D space. From Tire Rack (guess I should have read this first):
Directional (Unidirectional) Tread Patterns

A directional (also called a unidirectional) tread pattern is designed to roll in only one direction. It incorporates lateral grooves on both sides of the tire's centerline that point in the same direction and result in v-shaped tread blocks. These grooves enhance hydroplaning resistance at high speeds by pumping water more efficiently through the tread pattern. Unless they are dismounted and remounted on their wheels to accommodate use on the other side of the vehicle, directional tires are to be used on one side of the vehicle and are intended to be rotated from the front axle to the rear axle. If different tire sizes are used on the front vs. rear axle, the tires become location-specific and prohibit tire rotation unless remounted.

So if I flipped the tire left to right, the direction indicator on the side wall will be going in the wrong direction. So apparently, can't be done without remounting.

Sorry for the dyslexia!

 

If they are not directional then you can move them side tot side. I would first look at the wear on each tire. Get a tire wear chart and compare the wear. If one side is more worn then the other you would have to consider if the tire was under or over inflated. Also when you remove them besides checking the brake system check the tie rod ends and the ball joints. Depending on wear you may need an alignment which you'll have to wait until spring to get done. When was the last time this was done. Spring is coming even though it's 1* in my back yard this morning.

 

Thanks, Jagtoes. It is not so much that there is a problem, but rather that I prefer to be proactive in doing regular maintenance. No obvious wear now, and an alignment was done ~ 1000 miles ago. I regularly check tire pressure with a gauge since I can't get that from the OBDII as far as I know. (She who must be obeyed has an SRX that provides the 4 tire pressures on a screen.)

Stay warm!

 

I rotated the rears on my previous BMW since it was not a limited slip differential, same as my current XK. The drive side tire would wear more so to even out the rear wear I would rotate. They were also non-directional tires.

 

There are some who say not to rotate tires at all because you would then be masking potential problems. In other words, let them stay as they are and let them show you what is really going on with the alignment and balance- etc.

 

On the XK, assuming your alignment is decent, the wear on the tires is in the middle of the tread and is not from over inflating. Be careful when estimating how much tread is left by measuring from dead center, not the edge. This is common in cars with wide tires.

 

Just a general comment on directional tires
Understand what you're dealing with:
60 mph=88 ft sec. i.e. 1 mile a minute.
One tire rotates approx. 850 times per mile, or at 60 mph 14 times a second
Real world test show directional tires run 'backwards' perform just as well as when run 'forwards'.
Two things materially affect the tires resistance to hydroplaning, tread depth and tire pressure, the deeper the tread (within reason) the better resistance, and the higher the tire pressure the better the resistance.
Tread design has less affect than the marketing guys would like...
Regards,

 

Really, directional tires run 'backwards' are equivalent? What is the rationale for having directional tires? I don't really think there is a conspiracy by the tire companies. Would you point me to the documentation?

RE hydroplaning - presumably Tire Rack, Consumer Distorts, etc testing is performed on new tires (with similar tread depth), yet not all are equal. All I can say is I've had some pretty bad tires over my driving years.

Best,
wrair

 

wrair,
From the horses mouth, Tire Rack:
Mounted Backward on a Dry Track
Since we knew that directional tires are designed to emphasize wet performance, we didn't expect to find much, if any, performance difference with the tires mounted "backwards" on a dry track. We were surprised at how close it was. In this condition the Eagle F1 GS-D3 tires continued to provide predictable handling and good grip. If anything, mounting the tires backwards helped free-up the Cobra a little, slightly reducing its steady state understeer. With no handling quirks or surprises, the car ran 29.465 second average lap times, within 8/100 of a second of the times turned in with the tires mounted correctly.

Mounted Backward on a Wet Track
This is where we expected to find some noticeable differences since the tires would now be pulling water toward the center of their footprint, reducing the available traction. However, the lap times and drivers' comments indicated that the wet performance was still there. The Cobra ran average lap times of 30.387 seconds, just 1/100 second different than when the tires were mounted correctly.

Now, like the rest of us that do not accept marketing hype as truth, do the research on hydroplaning, tread depth and pressure, including the aviation formula for predicting hydroplaning speeds.
Them come back and we can discuss this subject.
Regards,

 

The P Zero Nero's on my Lotus are not directional FWIW and are Lotus specific tires (shared with MB SLS). If Lotus thought it was imperative to have directional tires, they would've...

 

I saw the articles a few months back and didn't think much of it then. It only makes one wonder what is the design/engineering concept and how was it proven out . It also makes me curious as to what is the thought/logic of the Conti DWS tires I have on the rear. They are marked to have one side mounted to the outside. You can see the different design of the tread pattern but what difference would it be to mount them the opposite way. Next thing we'll find out is the speed rating doesn't really make much of a difference .

 

My P Zero's also have an outside marker. Speed ratings are just for that; speed ratings. I am hardly ever going over 130, and if so, is only going to be for 5-10 seconds most. Likely to hit that speed twice a year at best.

 

Since I am old, I was a youngster when Radial tires first came out. Anyway, the Advice of the Day way back then was do not mix Radial and Bias-Ply tires on the same vehicle. The other Advice was to always run Radial Tires in the same direction, as keep the right-side tires on the right side. Left on the Left.... rotation could be done back-to-front only. I don't know the reasoning behind it, but it was so told.
I don't know if that is still accurate, or if it ever WAS accurate, but that was the deal back then. Having "ROTATION" arrows would assure that. "Outside" wouldn't.
I truly have no idea if any of the above info is ACCURATE, but it was the way people did things way.... back.... when....

 

Cee Jay,
You are sort of right about bias ply and radial tires;
Never mix on the same axle.
You can mix bias with radials if you put the radials on the front, not the other way round. The reasoning being the the sidewall flex in the radials will cause understeer, which is preferable to bias on the front that will induce oversteer.
Now finding bias ply tires is difficult.
I've never heard any rules about not rotating radials to their other side of the car.
The only thing that I remember has changed over the years is, in the old days, if you bought two new tires, you put them on the front. The reasoning was steering and stopping was more important than traction. Now the new tires are installed on the rear, because in wet conditions if you aquaplane you slow down to regain steering control, but if the rear looses traction, your in a spin, and for most drivers it happens so suddenly it's not recoverable.
At least that's what this white haired old boy remembers.
Regards,

 

So no hype. I purchased the directional tires ONLY because they matched what was on the rear (bought the car used).

Is there hype with the directional? Can't say I've seen that 'feature' advertised!

Regarding the reference to Tire Rack, that may be for one tire type, sample size is 1.

Tire Rack also says this:
From Tire Rack
Directional (Unidirectional) Tread Pattern

A directional (also called a unidirectional) tread pattern is designed to roll in only one direction. It features lateral grooves on both sides of the tire's centerline that point in the same direction and result in v-shaped tread blocks. These grooves increase hydroplaning resistance at high speeds by pumping water more efficiently through the tread pattern. Unless they're dismounted and remounted on their wheels to accommodate use on the other side of the vehicle, directional tires are to be installed on one side of the vehicle and are intended to be rotated from the front axle to the rear axle. If different tire sizes are used on the front vs. rear axle, the tires become location-specific and tire rotation is prohibited unless remounted. Two of our best rated all-season directional tires are the Michelin Pilot Sport A/S Plus and Bridgestone Potenza RE970AS Pole Position. - See more at: Symmetric, Asymmetric, Directional, Unidirectional - What Does This Mean? - Choose the Best Tires with Zig | Tire Rack

Or how about this from Michelin!

From Michelin "Proper use of directional tires:
Directional (Unidirectional) Tread Pattern

Once directional tires are worn greater than 50%, there is no negative effect of running them in a direction opposite to the indicated direction of rotation.
Operating directional tires from new to 50% worn in the opposite direction of that indicated on the tire will result in premature onset of irregular wear, excessive noise levels and significantly reduced tread life.

In any case, I realize I can not rotate my tires (without remounting).

Thanks for the info and discussion.

wrair

 

Michelin tires, about the most worthless hunks of used recycled condoms on the market. I would never in a trillion evers trust anything they produced or said. They are only rated High because they refuse to publish most of the Negative Reviews on their own site. Believe me, I know. I would also seriously believe that they pay "unbiased" sites to only post positive reviews. Seriously. If (when) you crash because the Mushilins you bought either blew up or refused to hold the road, remember this comment.

 

Thanks, Cee Jay. But frankly, the BEST tires I have owned were the Michelin's oem'd by COSTCO for my Dodge minivan. (Not a very sporty car, but very functional.) They were smooth, great in all conditions (never needed snow tires). Never had a flat, and they lasted a very long time. And I had a few emergency stops with them (my fault). I also like my Michelin X-Ice tires on my Buick, although they are a little squishy.

At this time, the Michelin's on the JAG sure beat the Dunlop's that were on the front, but then the Dunlop's were way past replacement. If the back tires didn't have brand new Michelin's, I probably would have got something else.

The Michelin's on she who must be obeyed's XRS (20" rims, oem) are pretty good, too, I think.

My experience with Michelin's: n=5. I purchased the COSTCO's, Xs and for my old Intrigue (can't remember the model) based on Consumer Distorts presumably not influenced by Michelin (and also other sites input).

~wrair

 

Guess I just have a higher standard when it comes to tires. As long as they fit your needs, that all that is required. Hope you have many happy miles with them.

 

I recall back in the 60's my tire place told me only to move the fronts to the rears but only on the same side for my radials. They said some BS about break in and rotation direction and by putting them on the other side you could damage them. I was to young to know if he was right or wrong but it wasn't a problem because I used to wear out the rear tires sooner then having to rotate them.