Do Car Tires Have an Inside and Outside?

This sounds bonkers to me...

I've heard of tyres (tires) having a prefered direction of rotation...but of course if the 'Outside' is marked then the direction of rotation is reversed depending which side of the car it is mounted.

On the other hand it would be a good ides to have a raised rib oround the outside to offer some protection against scrubbing against the kerb...

Does the Tyre Manufacturer have a website....?

I feel your comments are probably correct as inside and outside do not imply that the tire may only revolve in a particular direction.....

Maybe the outer wall is reinforced or something, for Lady curb drivers?

Look at the tread on the left vs the right - see if it's oriented in the same direction, then you'll know.

Well now, I clicked on the link you provided and found this

http://www.tirerack.com/images/tr_ownersmanual.pdf

Check page six. Seems there are two types of tires. Yours seems to need the correct side facing outwards. I think the concept is sound in that the tires are optimized for handling and grip. The downside is that you need extra tires if you want to rotate them!

The downside is that you need extra tires if you want to rotate them!

Hi Vulcan,

tis depends on HOW you rotate tires!

Doing it Fr/Rl and Fl/Rr, you need a second set of tires... but doing it Fr/Rr and Fl/Rl, it will work fine!

Uppercase: front/rear Lowercase: right /left.

In my car (Subaru) the manufacturer recommends doing it the second way

Vulcan is right - what about if the spare?

what about the spare?

I CANNOT AFFORD HAVING A SPARE!!!!!!

Now I've got something new! My car's manual says this.

I would think that this would even out the wear much better than keeping the tires on the same side (just swapping front and back). Even so, I remember the look on my mechanic's face when I told him to rotate the tires this way. He didn't say anything, just did as I said. But his head scratching told me that he didn't entirely agree. Now I know why.

Oops! Forgot about the spare. The right rear becomes the spare and the spare becomes the left front.

most cars now come with those silly little doughnut tires (tyres) that only allow up to 50 MPH unless you opt for the full size spare.

Mr. Vulcan:

What kind of tires do you have? cross over rotation is ok for NON-Radial tires and spare rim and tire is needed if you include it in the rotation program.

The newer steel belted radial are moved front to back only. The spare furnished with a new car is a miserable undersized thing on a rim to criple home or to the dealership with.

What kind of tires do you have?

'Know what? I never bothered to check! They're Yokohama and I've had no problems with them. Then again, I hardly ever exceed 80kph and typically proceed at 60kph.

I've got a spare rim and tire (same brand and model) and I do include it in the rotation program.

Oh, dude, catch up! You are WAAAAAAYYYYY behind the times. The cross- over rotation has been standard for more than 20 years, and at that time, ALL cars had radial tires.

Actually cross-over rotation was standard in bias ply days, too. It has become less of a standard over time, with some cars having no way of rotating tires, at all. Many high performance cars have different sizes on front and rear, and many have directional treads which cannot be switched from side to side.

• Oh, dude, catch up! You are WAAAAAAYYYYY behind the times. The cross- over rotation has been standard for more than 20 years, and at that time, ALL cars had radial tires.

What planet have you been on, with steel belted radial ply tires if you change the direction of rotation by switching sides, you will dramatically increase the rate of wear and dramatically shorten the life of the tires.

For at least the last 20 years I have know that unless you reverse the way steel belted radial tires are mounted on the rim, the only rotation you should do is from froth to rear.

He is from planet earth. Cross over rotation of radial tires have been a common practice in the last 20 yearss. Believe me I have been selling tires for much longer, and doing this with no problems what so ever.

Rotating steel belted radial ply tires doesn't cause any problems with traction or handling but rather increases the rate of wear. The way it was explained to me is as follows:

Because the steel thread that holds the tread shape and stops it from distorting and as a result the tread pattern distorts more. The diagram above shows what I am talking about with the tread block being distorted due to the opposing forces of torque and friction. This distortion causes the leading edge (the edge that touches the road first) of each tread block to wear faster than the trailing edge (the edge tat contacts the road last). As a result the tread blocks have a slight taper with the leading edge being slightly higher than the trailing edge.

As a result the tire wears down along this slightly tapered line but it does wear at a constant rate once the tapering has been established.

However, if you change the direction of rotation the tires will quickly wear till they establish the tapering in the opposite direction. This happens very rapidly and does not overly effect the handling characteristics but it does dramatically increase the rate of wear until the tread is tapered according to the new direction of tapering.

My understanding is that this only happens on the driving wheels and is not a problem on the non driving wheels so I would not expect to see to much of a problem when changing the direction of rotation of these.

So, in answer to;

• I have been selling tires for much longer, and doing this with no problems what so ever.

I wouldn't have expected to see any problems with the handling etcetera, however, the tires would have worn out faster than if they were not rotated in a way that switched the direction of rotation.

That's the problem according to the way it was explained to me ant as I havn't actually done any hands on research myself it may be something completely different, so if anybody else has a different theory pleas feel free to correct me.

I like it. Certainly I'm familiar with that kind of wear pattern on motorcycle tyres, perhaps because on modern soft sports motorcycle rubber you can see it happen before yor eyes, thrash by thrash!

These days we seem to get punctures often, which corrupts such wear management.

Masu, you miserable smegging wretch. You're trying to confuse us all!

Actually, your description sounds pretty good -- although you've switched things around a bit. (And in addition there's the theory... and the practice. It turns out that there appears to be a discrepancy. But more on that in a minute.)

You've drawn the leading edge higher than the trailing on the two blocks that are not distorted. But you say: "This distortion causes the leading edge (the edge that touches the road first) of each tread block to wear faster than the trailing edge (the edge tat contacts the road last)." If the leading edge wears faster, then wouldn't you expect it to be lower (worn more), not higher? If you make your drawn distortion even more dramatic, the trailing edge would be lifted almost clear of the road under the distortion from torque. So you'd expect that the leading edge would indeed wear faster (contrary to your drawing and your statement, "As a result the tread blocks have a slight taper with the leading edge being slightly higher than the trailing edge.")

I went out and measured the degree of wedge-shaping of my tread blocks. Mine are shaped as you've drawn them: higher at the leading edge, which is contrary to your assertion that the leading edge wears faster. So if the leading edge actually wears less, why?

In addition to measuring tread on my drive (front) wheels, I measured the rears, too. (I say measured: actually, I went out with dial caliper in hand, but found the wedging so slight as to be unmeasurable, given the rounded profile of the groove between tread blocks. So instead, I used the side of the instrument as a straight edge, and compared gaps at the edges of the tread block before and after the block under examination. The result: front and rear, the wedging is the same. But the rear tires are subject to braking torque, which acts in a direction opposite to drive torque. (These tires have not been rotated.)

So, if the wear pattern has to do with distortion from driving torque, then the rears, which are subject to braking torque only, should wear in the opposite direction... but they don't.

Way back in my motorcycle road racing days, we mounted directional tires per the manufacturers recommendation, with the directional arrow facing one way on the front (predominately braking torque) and the other way on the rear (predominately driving torque). In theory, this would make the predominate torque tend to paste down the ply splices and the tread splice (all of which ore overlapped the same way) rather than peel them up. (It's hard to imagine that, once the tire is vulcanized, these splices could come adrift, but...) I have a dim recollection that this same theory was applied to bias play auto racing tires, too. Now, the directional arrow on radial car tires faces the same way, front or back, so it has more to do with tread pattern than internal construction.

So why does the trailing edge wear more than the leading edge? I suspect it is related to the nature of ordinary rolling tread squirm, and little influenced by torque. In another discussion, we debated the use of actual circumference vs loaded radius for speedometer and odometer calibration. When that discussion came up, I'd coincidently just calibrated my speedo on my prototype vehicle (with which I will soundly trounce all competitors in the Automotive X Prize!). I'd used loaded rolling radius, (which I have used to tractive force calculations, etc.) But of course loaded radius decreases with decreasing tire pressure, but circumference remains essentially the same. So if the tire makes one revolution, it has to travel one circumference's worth, not 2pi r's worth, right. Turns out, in practice, the loaded radius calc is much closer for bias ply tires (which the vehicle temporarily has on its single back wheel) but for radials, the figure seems to be half way between the two calculations. For the bias play tire, the difference was huge (about 2" per revolution out of a 58" or so circumference.)

I think, but I'm not at all sure, that the longitudinal tread squirm is asymmetric. The steel belt and especially "layer", if present, is inextensible, so the tread surface (1/2" further from center) must compress as the tire flattens out on the road. As a tread block comes into contact with the road, it simply rolls into place with little scrubbing. But as it leaves the road, it springs back when enough of the tread block has left the road to allow slip. That slip doesn't affect the leading edge (already clear of the road when the spring back occurs) but does affect the trailing edge.

Plausible?

Hi Ken,

Sorry about the confusion, the way I have explained it doesn't make sense, so I will attempt to explain it differently and see if it makes sense. Because the steel in the tire carcass doesn't stretch it causes the tread blocks to distort and the leading edge distorts more than the trailing edge. As the leading edge distorts more than the trailing edge it slips on the road less and therefore wears slightly less than the trailing edge.

Now, the more I try and explain the picture in my head the more I feel uncomfortable with the explanation and the more I believe it is nothing more than a consignment of complete procreating male bovine excrement (You'll have to figure that bit out yourself). That's what is great about CR-4 it makes you think about things and query whether you really do know what is happening.

However, regardless of the physics, you measurements have confirmed that there is definitely an asymmetric wear pattern on radial ply tires that is direction of rotation dependent. That would tend to indicate that the claim that there was only a problem with the earlier designs of radial ply tires and that this problem had been subsequently overcome is in fact not the case.

Given what Ken has measured I am no longer convinced that what I was told is in fact the case, so, some time over the next day or so I will do some research and post the results here. One way or the other I am going to get to the bottom of this.

This is turning really interesting, can't wait to read more. Sadly i know diddly about the mechanics of tyres but I do know a fellow who's designing and making tyres for vintage cars - they're winning races. Not radials, well not sure what they are to be honest. http://www.blockleytyre.com/

It's interesting to see how your tyres are wearing on a particular vehicle subjected to everyday driving but there are some influences such as inflation pressure, driving style, type of road, weight distribution and so on, that could affect the wear pattern surely?

I bet the tyre manufacturers are less than free qith the years of research they've put into understanding the whole gamit.

Ok folks, I have done more searches than I can count and read so much on tires that I think I am developing a tread pattern on my eyes.

I did find a couple of sort of obtuse references to radial ply tires needing to have a consistent direction of rotation during their life, but no explanation of why. There were however numerous tire rotation patterns that had both cross over and non cross over rotations and may statements that tires should be rotated according to the vehicle manufacturers guidelines . However it you look at the vehicle manufacturers guidelines they say tires should be rotated according to the tire manufacturers guidelines.

The whole thing seems to have this "It's somebody else's problem so ask them!" feeling with nobody really knowing or caring what is really going on.

However, as we have seen from Ken's measurements there is definitely a rotation dependant wear patter on steel belted radial ply tires so there is definitely something going on here.

Just to add fuel to the fire, I consulted my brother who is a driving instructor and examiner for a car club that handles exotic cars like Porsches, Ferraris, Lamborghinis, Aston Martin DB9, Bentley Continental GT and I believe they are trying to add a Bugatti Veyron or equivalent to the fleet. Yes I know, my brother is a really lucky bugger and it really pisses me and the neighbors off when he brings their latest acquisition home for a test drive.

Anyway, enough of the turning green with envy and disgust, I consulted with him and they absolutely never ever reverse the direction of rotation of the tires on any of the vehicles and if rotating from side to side have the tires removed and remounted on the rims so the direction of rotation does not change. Now, I don't know how relevant this is because some of these vehicles have highly specialized tires that have a defined inside/outside as well as direction of rotation but it is worth noting that they stick with the direction of rotation rule on all vehicles regardless of the type of tire or vehicle.

So, what does that all add up to? Well, I am buggered if I know! All that I have been able to ascertain is that trying to get a straight answer from a tire or car manufacture is like talking to talk to a concrete pillar about the use of reinforcing and aggregate and the frustration give you a headache that can be measured on the Richter Scale. Actually, I am told that whilst suffering from concussion I had such a conversation with a concrete pillar, so it's even worse than that.

I think there is only one way we can truly find out what is going on and that is to do the research ourselves and figure it out, so, if anybody is willing to start up a thread and do the research please feel free to do so.

Now, where did I put that headache medication!

Awww, just when you think you're getting somewhere! But well done masu, thanks for all that hard effort, have a good lie down.

I do remember seeing virtually asymptotic 'feathering' on a bike tyre once, and I have a feeling it would have been the trailing edge from memory.

In my road racing days, I was amazed at how sticky our tires were. After ten laps or so, you could pull away stringy gooey pieces of rubber from the tire -- it's amazing they lasted as long as they did. (And the patterns was, as you said, asymptotic -- but I can't remember on which edge -- no do I remember if the pattern was reversed for front and rear tires.) I think when we were running a small bike, we would get about 1000 miles on a tire, replacing them about halfway through a 24 hour race. Most of our used tires had almost no wear down the center -- so we could have sold them to a conservative street rider, and they be good for 10,000 miles more.

On motocross tires, the wear pattern is much more obvious, and it is the leading edge that wears, very dramatically so. We'd reverse them on the rim to use the other side of the tread blocks, if we were feeling cheap (but we'd lose some braking effectiveness). I think in motocross the dynamics are much different, because the tire is almost always spinning (slipping) relative to the ground.

Once, on an Italian hilltop in the middle of Nowhere I came upon a couple of dozen bikes outside cafe. There were tyres there that made me reappraise my place in the Motocycling cosmos. Never seen 'road' tyres melted transversely in the same way before or since, front and rear!

"The downside is that you need extra tires if you want to rotate them!"

What's the point of that?

Yes, I have seen the error in my thinking. Thanks.

The reason why I thought that was my car's owner's manual recommended that I rotate my tires in both front and rear and left and right direction. r&ddoc says he rotates them front and rear only (I guess that doesn't make it rotation ).

If my tires are directional, that means I can't exchange them left and right. Is that bad? I don't know. My car is a front wheel drive and the engine is mounted perpendicular to the cars front-to-rear line. I've noted that the engine seems to be sitting more to the right than the left which makes me think that most of the car's weight is on the right side.

Anyone care to voice an opinion? I'm not a car buff.

Typically in the past rotation meant the old school way of doing it. Which indeed was to exchange sides and from front to rear. if you have regular tires then this still holds true.

If you have a directional tread then rotation is from front to back only.

Where the kicker comes in is with some new cars the front and rear tires are not even the same size. There fore they cannot be rotated at all.

The original reason for rotation was to maintain treadwear evenly on all contact surfaces of the tire. With new tire technology tires have a flatter profile. With new auto manufacturing technologies vehicles are able to maintain the flatness with the road surface even in cornering.

Now Vulcan to answer the last part of your question:

I've noted that the engine seems to be sitting more to the right than the left which makes me think that most of the car's weight is on the right side

The answer to this is when your car is aligned professionally, this is providing they are very experienced at this, they will set up you car to account for the extra weight that is commonly on the drivers side of the vehicle. This is also to account for the additional weight load of the driver.

By properly adjusting the camber of the frontend when the additional weight of the driver is added to the car, the tires then rest flat on the road. Typically the weight ranges will be in approximate ranges from 150 - 200 lbs 200-250 lbs for driver weight.

A good alignment tech will talk to the driver to visually gain a weight assesment as well as some driving style from a little conversation then set of the car accordingly. If your alignment tech doesn't do this then your not getting full value from your alignment. My alignment guy has even had me sit in the car to check his work.

Experience is the best value not price.

A good alignment tech will talk to the driver to visually gain a weight assesment

Good God! Now, it makes sense! The last time I bought new tires, the shop installed them as part of the price and threw in a free alignment.

The technician asked me what my weight was. I thought he was just being friendly though I found the question a bit unusual. He asked a few other questions like: who else drives the car? How many passengers do I normally have?

He didn't explain the reason for the questions and I didn't bother to ask. I just thought he was a real friendly type .

Sounds like you have a real good alignment tech there Vulcan.

I would be sure to continue to use him.

I've heard of tyres (tires) having a preferred direction of rotation...

Pattern / thread design depends mainly for what speed (and use) tires have been manufactured for.

The direction of rotation is to eliminate water / snow / mud from the grooves by centrifugal force.

Some brands have an arrow indicating the direction they must rotate, other have the name of the manufacturer and tire spec on one wall (outside), and the opposite (inner) wall blank. This is the same than indicating "Inside or Outside"

...now, if you like some adrenaline every now and then due to Aquaplaning (Hydroplaning) just let them mounted as your "reputable" tire guy did!

speaking of hydroplaning. I understand some makers will no longer allow the cruise control to be activated when the windsheild wipers are in use.

I think a great idea, but no help for icy conditions.

the reason you dont want cruise control during rain is that if you start to skid, you tend to get out of cruise control by hitting the brakes. That is exactly the wrong response to a skid.

Uh yeah, I understand hydroplaning. It was more a point to the preventative technology employed by car manufacturers.

And you also might consider that when hydroplaning the tires actually leave the road surface. With cruise control engaged this is a serious problem. The tapping of the brakes a secondary issue.

As I was taught, let up the gas, hold the position straight and relax. It's worked every time for me.

But thanks all the same

The last time I visited a tire shop i noticed that some tires are sold in pairs.

The design seems to be direction specific. I did not look for any special markings.

A tire marked inside and outside may not be direction specific and I would say inside means inside and outside means outside irrespective of the side of the car.

It seems absurd to specify an outside on a tire and use that side on the inside on the other side of the car. Left / right would have been more appropriate.

The last time I visited a tire shop i noticed that some tires are sold in pairs.

As far as I know it is advised to buy tires in pairs, the new ones go always in the front wheels.

Actually,

The new tires should always be installed in the back , not the front. Read this article to understand why...

Hey..great link...

I was all fired up to take the p*ss but I can't argue with their theroy or results..

Nice one!

I was too lazy to write it all but I live where a lot of snow falls in the winter and did it the wrong way one time. I got lucky to only "hit the ditch" without injuring anybody. The tow-truck driver explained to me the error of my ways....lesson learned.

Hi Rick@cae,

Good point!

But the article you mention says: "However due to the front tires' responsibility for transmitting acceleration, steering and most of the braking forces on front-wheel-drive vehicles"

As my car is All Wheel Drive, situation might be different. The Subaru Service guys told me to replace them in pairs, new at the front. It´s a pitty the Michelin people did not do this test on AWD and 4WD vehicles as well!

Damn !!! Forgot about the AWDs....

You're right, the rules might very well be different for those. I was very reticent to go to front wheel drive and held out as long as possible. I was under the impression that it'd be very hard to regain control in a slide (again, I learned to drive in winter). I finally got one and have been an adept since! Never owned a 4 wheel drive/AWD so didn't think of it...

Thanks for mentioning it...

regards,

What does this guy use?

The middle one seems to be directional-radial...the 2 outsides ones are Kodiak soles !

Dr. Scholl's?

What does this guy use?

Hi Del,

have seen another video of the same guy with his weird bike totally out of control landing on the pavement!

It's affectionately called a 'monowheel', and more examples can be found here:

http://www.douglas-self.com/MUSEUM/museum.htm

in the Museum of Retro Technology.

Just reinforcing the point that front-drive gives rise to a heavier car. The rear wheels/tyres/hubs/ and lots of other parts are over-specified for their function, partly to keep the same wheel/tyre front and rear.

· Just reinforcing the point that front-drive gives rise to a heavier car. The rear wheels/tyres/hubs/ and lots of other parts are over-specified for their function, partly to keep the same wheel/tyre front and rear.

I am not quiet sure about the logic behind this, wouldst thou care to elaborate somewhat?

Sure, I'll let you have the paper but as was nicely put somewhere in the thread, the back wheels don't bear a lot of weight so for mass efficiency they could be a lot smaller than the front (then the tyres might wear at a more evenly). The forward weight bias means more load on steering components and, I would argue, has contributed to the jump in the fitment of power steering to smaller and smaller cars (along with growing tyre/rim width). Weight breeds weight, meaning if you save some in one place you can then save a bit somewhere else. Knock a bit of weight off the whole and your engine and brakes can become that bit lighter, secondary savings.

Also the move to wider tyres means more 'scrub' in corners for the outside of the tread. I believe this will affect the steered wheels more than the non-steered wheels, making for more wear on the front. Anyone corroborate?

I would concur...

We are generally driving cars which are oversized...so they need bigger wheels wider tyres etc...it is a vicious circle.

Smaller, lighter, skinnier tyres, don't then need that huge engine...

Yet you still have decent performance.

And the trend to wider tyres increases rolling resistance and makes a measurable contribution to wind resistance too. Lads who stick huge wide wheels on their hot (as in warmed by their 1200W amps and poor alternators) hatches would do well to note, soon I'll be off on the subject of suspension lowering - oh no!!!

I don't think it matters if the car is front wheel, rear wheel or all wheel drive. Lock up the front wheels (or lose traction) and a car wants to go straight. Lock up the rear wheels and the car wants to swap ends. If you live in a freezing climate, try it on a deserted snow covered parking lot using your emergency brake (which on most cars just actuates the rear brakes).

However if you are trying to make a turn and the car keeps going straight, the results can be as bad having the rear end come around. Also in winter, having good tires on the drive wheels can keep you from getting stuck.

I was very reticent to go to front wheel drive and held out as long as possible

You know what? same happened to me: I used to drive rear wheel, passed to front wheel (amazing difference)... and finally passed to Subaru´s AWD: THIS IS IT!!!!

I have been driving these cars for the last 15 years and can tell that their behavior is completely different to those with front or rear drive. In my opinion, they are much safer under any condition (even in mud or pebble roads)

regards,

Hi r&ddoc

• As my car is All Wheel Drive, situation might be different. The Subaru Service guys told me to replace them in pairs, new at the front. It´s a pitty the Michelin people did not do this test on AWD and 4WD vehicles as well!

That's interesting, we are currently on our fourth (Sports Wagon) and fifth (WRX Turbo with engine modifications to give it even more power) Subaru and everybody I have spoken with and that includes Subaru, have always said the new ones must go on the rear..

Even with a car like the Subaru WRX the front tires are prone to wearing faster because then are solely responsible for steering and around 80% responsible for the breaking while the acceleration is about 80% rear and 20% front. The all wheel drive WRX is an improvement on the front/four wheel drive models that came earlier but they still eat front tires faster than rear tires.

Where the difference may come into play has nothing to do with which wheels are doing the driving bur rather how the breaking is done. The problem arises if you get the rear wheels aquaplaning before the front wheels which usually results in the back going faster than the front. The resultant reversal of the front and rear of the vehicle can really mess up you day not to mention your underwear. However, if you have anti lock breaking systems and all the other electronic bells and whistles many cars now come with it becomes difficult, but not completely impossible, to get the rear wheels aquaplaning before the front so you may be able to get away with it in most situations.

Hi Masu,

Yes, I had forgotten that Subaru´s AWD have more traction on the front than in the rear wheels (80/20) when on a flat road.

Therefore I agree with you about putting the new ones on the rear!

Hi r&ddoc,

The first Subaru we owned was purchased new and was a 1983 touring wagon with an automatic transmission and more bells and whistles than you could imagine. In normal operation it only drove the front wheels but if you ever felt the car loosing traction or were approaching an area that you knew or thought would be slippery you could engage 4WD on the fly by operating a small push button switch on the gear selector.

The steering in it was the absolute best I have ever come across and had a turning circle that was phenomenally tight. Even though the steering was incredibly light and required little force or movement to produce a response it gave magnificent feel. It took some time to become accustomed to but every vehicle I have driven since, including later model Subarus, I have found the steering disappointing at best and atrocious at worst. Many people that drove it just didn't have the skill necessary to come to grips with the complete lack of slack and the sensitivity and would try and correct when no correction was necessary. The result was a small drive induced oscillation that caused the vehicle to meander back and forth across a lane or the optimal path. Personally I loved it and after a couple of hours found the sensitivity and directness fantastic.

Another thing that I found good was the hand/emergency/parking bake. Most hand breaks work on the rear wheels which makes them next to useless in an emergency and prone to locking and spinning the vehicle. However in this vehicle they worked on the front discs and pulling the hand break on resulted in the vehicle coming to a stop frighteningly quickly. Unfortunately Subaru no longer use this and have reverted to the hand brake operating the rear wheels.

Even the suspension was unusual and the rear wheels were mounted on a torsion bar that was mounted forward of the center of gravity. As a result when you accelerated the vehicle didn't pitch nose up but rather settled lower on the road.

It had the first electronic instruments and trip computer I had seen in a vehicle and at night it looked like something right out of star wars. One night I picked up a driver on a dark and lonely road who's vehicle had broken down and he commented that it looked like something that was light years ahead of anything he had ever seen. He was totally flabbergasted when I revealed that it was around 10 years older that the vehicle he was driving.

We kept that vehicle till earlier this year and only got rid of it because we were moving interstate and it wasn't worth shipping a 23 year old Subaru half way across the country. None the less it was heart breaking for both my wife and myself the day it finally went to that great car yard in the sky. I would have loved to restore it to new condition because we both loved driving it so much, but we no longer have the space and I can't do much of the work any more.

very cool link.

of course I just installed new tires 2 days ago at a reputable shop. They made no mention of this and guess what. You betcha, front axle. Of course they did.

cr3

Possible, but all the tires I have seen have an arrow that describes the direction of rotation. Double check for an arrow.

Basically, directional tires have an asymmetric tread. All high performance tires have this.

Check back with your installer and see if they are installed correctly.

Yer motorcycle tyre isn't asymmetric(!), but it's mono directional. There must be factors other than purely the tread design at work in this case.

Basically, directional tires have an asymmetric tread. All high performance tires have this.

Actually this is not quite true. There are "directional" treads, which in general look "V" shaped. These have directional arrows. What that means, is that once the tire is mounted on a wheel, then that wheel can only go on one side of the car.

Then there are asymmetric treads. These have a definite inside and outside. Often the outer sidewall is a little stiffer than the inner, and there may be additional internal differences. These tires are designed for the fact that, in hard cornering, the outer wheel is more heavily loaded, and the outer edge of the tread on that side is more heavily loaded yet.

Then there are "regular" tires which can be put on any old way. Even these are unintentionally asymmetric, (for the nit-picky-technical types) because every tire has some degree of "conicity" in addition to radial force variation, lateral force variation, and runout (lateral and radial). Conicity is the tendency of a tire to act as if it is cone shaped, tending to pull to the right or left. In most tire plants every single tire is measured for each one of these defects, and the tread is ground slightly to correct problems. Tires that require significant grinding are often downgraded and not sent to OEM's.

But in any case, there are three different mounting routines, and if you change tire types from original, then the car manufacturer's rotation chart may be entirely wrong.

The basic answer is, yes! Some high end market performance tyres are tailored for each corner of the car. Providing you don't go too far or too fast on them, it wont hurt to have them fitted the wrong way round. Are you using a space saver?

Thanks, everyone, for answering my question. I just off the phone with the owner of the tire shop. As soon I as told him that I had a question about my new Fuzion HRI tires, he knew what I was calling about. Here's what he had to say.

Because Fuzion HRI tires are directional, the "Inside" and "Outside" labels don't apply. What matters is having the treads face the same way (they do). Fuzion has provided tire dealerships with a service bulletin about the mislabeling, but some tire techs forget to pass this message along. In a perfect world, Fuzion would have ground the labels off the tires, or corrected the mold. But it's a long walk back to Eden.

A nice little vignette of the real world vs the ideals of QA.

Glad that's explained! Was beginning to think I was having a 'through the looking glass' moment.

It wasn't anything to do with oval-racers and their penchant for larger diameters on one side than the other then??

It probably does, Wrenched. The "Inside" and "Outside" labels may cause some race fans to think they're getting some high-performance treads, but the Fuzion HRI is just an all-season tire.

Let's hope you don't have an insurance claim and have to fight that one out in court. I would put them on according to the directions just in case even with the notice in hand.

Ever heard Ron White's routine about the "tire guy" who went to "tire college" and, who must have been absent on "lug nut" day? Funny!

Ron White

Your tire slip up. The tires if marked as such have tread designed turn in one direction. Have had to pay attention while changing snow tires on a few cars.

Yes , the outside usually has a white stripe around it. I quit worrying where the tires come from and go to a long time ago. I change my tires twice a year for summer and winter and it became too much of a hassle. It doesn't seem to make any difference on my old van. I just put the most worn ones on the rear to equalize the wear because the fronts tend to get the corners scrubbed off. And it's not because it's out of alignment, its the nature of the beast. If I get a thumper, it gets banished to the rear. When you buy used tires, how do you know where it's been? That's when I began to question this whole tire rotation thing.

Yes, all four tires should show "outside" if the tires are correctly marked. If the tires are incorrectly marked, they should be sold as "blems". These days there are three distinct way to design, build and mount tires.

For details see my response to Anonymous Hero.

if they are directional tyres

they have to be used the right way

otherwise instead of pushing foreign bodies

away they will pull them in loosing surface adhesion

If you really want to roate the tyres to even out the wear then you can get the tyres taken off the wheel rim and rotated this way to ensure that the direction of rotation is always correct. This may cost a little more, but will even out any mis-alignment you may have within the front wheel alignment (tracking) and allow the fronts to be fitted to the rear etc.

I've just had a new set of alloy wheels & tyres delivered from a reputable internet company and found that one of the four tyres had been fitted incorrectly which meant that I had three wheels/tyres with the same directional rotation. The manufacturer recommended getting the tyre removed and refitted correctly before driving the car...obviously they paid for the refit.

Moral of the story: Humans make mistakes...it's what we do best!

As long as the tire is mounted with the "Outside" marking on the same side as the outside of the wheel, (the exposed side) you can theoretically move it to any position on the car.

That says nothing about the required rotation pattern. I have always been taught that radial tires should not be rotated from one side of the car to the other, only front to back. They take a "set" in use. The right side tires are "set" for a clockwise rotation; the left side for anti-clockwise.

Check the tire manufacturer's recommendation when rotating your tires!

Hi fellow petrol heads,

There seems to be a whole stack of what would seem to be old wives tales going on about tires and rotating them. From experience and what I have been informed by the tire manufactures (not the guys selling and installing the tires) the following applies.

• On the symmetry front there are four types of modern high performance tires:
• Symmetric tires: are not sensitive to the direction of rotation or the relation to the inside or outside of the rim.
• Directional tires: are tires that are sensitive to the direction of rotation and have a tread pattern that will move water from the road better when rotating in one direction than the other. While all four tires on a vehicle are identical you need to mount them on the rims according to the side of the vehicle you intend to use them. They normally have a arrow on the wall that indicates the direction of rotation. If you do not mount them correctly you run the risk of loosing traction in the wet on one side sooner than the other which will cause the car to start spinning.
• Asymmetric Tires:. are not sensitive to the direction or rotation but like the rims have an inner and other side and need to be mounted so they match the rim. All four tires are the same and can be used in any position on the vehicle. Normally these will have something on the wall that indicates the which wall needs to be on the outside and sometimes also have the inner wall marked accordingly.
• Directional Asymmetric Tires: are the ones that need to be sold and mounted in pairs. Not only are they sensitive to the direction of rotation but they also need to be mounted on the rims sot the outside of the tires correspond to the outside of the rim. The tires are different and so need to be used only on the side of the vehicle they are designed for. This type of tire will be marked not only to show the direction they need to rotate but also which wall should be installed on the outer side of the rim.
• Spare tires for older vehicles were just the same as the tires normally used, however with the introduction of tires that are asymmetric and or sensitive to the direction of rotation you cant always carry a tire and wheel that is identical to all the tire/rim sets used on the vehicle. As a result manufacturers started to have spares that were not sensitive to rotation or mounting orientation. These however were not meant to replace the damaged tire/rim but to get you out of trouble and to a dealer that could repair or replace the damaged tire.
• Replacing tires should be done in pairs with the newer tires going on the rear. The reasons for this are in wet conditions the newer tires will have better road holding characteristics and so will be less likely to cause asymmetric braking forces that can put the car into a spin. While putting new tires on the front will not produce right/left asymmetric breaking forces it can result in the back aquaplaning sooner that the front thus causing the vehicle to spin.
• Rotating tires in no longer the simple front to back right to left swap the spare out that it once was. There are a whole host of factors that now need to be taken into account:
• First off most tires sold to day are steel belted radial tires that produce wear patterns that are sensitive to the direction of rotation. If you take a worn steel belted radial and place it on the other side of the vehicle the reversed direction of rotation will accelerate the wear and often produces an unbalanced tire that will cause vibrations. Basically once a steel belted radial tire has been used for a time it becomes sensitive to the direction of rotation and if you wish to use them on the other side of the vehicle you will need to have them mounted on the rim in the opposite relationship.
• If you have tires that are sensitive to the inner and out orientation you will not be able to change the side they are on regardless of whether they were directionally sensitive because once they have been used they will become sensitive to the direction of rotation and will wear faster and may cause vibrations due to asymmetric wearing of the tire,
• If you have a spare tire that is designed to only act as an emergency tire that gets you to somewhere where the damaged tire/rim can be repaired you can't utilize this in the rotation.

Basically with modern tires you are pretty much stick with just swapping the front with the rear on the same side but you need to be careful that the tires with the least wear are on the rear. With front wheel drive vehicles this can be somewhat problematic because the tires on the front are the ones doing all steering, propulsion and braking while the rear wheels are only holding up the back so it doesn't scrape on the ground. As a result the front tires are the ones that cop all the wear and if you swap then with the rear tires you could be in for an exciting time.

The only satisfactory solution I have been able to come up with for front wheel drives vehicles is to use the tires till the front ones are worn out then put the ones from the back on the front and put two new tires on the back.

As for the spare, well it depends greatly on what type of tire you are using but you need to be aware that having tires are worn differently on the same axis can be dangerous so you are more than likely up for two tires if you damage or wreck one.

Just as an aside I have seen many people come unstuck with trailer tires. Radial ply tires are designed to distort if subjected to sideways forces and keeps more of the tire in contact whit the road during cornering. However with a trailer sideways distortion of the tires can lead to no end of problems so in most situations it is better to use cross ply tires on things like trailers and caravans. There are however, some trailers and caravans that are designed to use radial ply tires so it is worth checking with the manufacturer on what they recommend.

So, in response to Moose's question,

• On the passenger's side, the outer walls of the tires have raised lettering that says "Outside". Do car tires have an "Inside" and an "Outside"? If so, should the outer walls of all four tires read "Outside"? Did my reputable tire guy mismount the tires on the passenger's side?

Yes, some tires do have an inside and outside just like the rims and it would definitely appear that you tire guy didn't do his job properly. More importantly the improper installation and use of tires can not only void your warranty on the tires but you're your insurance policy, so I would head back to him first thing tomorrow morning.

PS I apologize if I have repeated what others have said, it's just easier to put everything down as I think of it rather than edit out the bits that have been covered by others.

I always put the air into the inside.

Funny thing about air. I had a tire (tyre) ruined by a pothole (what's the english equivalent?) and had to have it replaced. The tire store used nitrogen to inflate the tire. I have noticed a huge difference in the variation of the tire pressure wrt. temperature. Not that I'm going to run out and change the air in the tires! That only has to be done every 5000 miles along with the $80 oil changes...

Oh, the latter isn't a joke if you own a VW.

I noticed that one of the tires on my wife's van said "Outside" while I was wahing her car the other day. I wondered about this because I had not seen it before. I will have to go back and look closer at all of them. Thanks for the timely (for me) discussion.

Is all this inside outside really better or is it just a novel way for tire manufacturers to sell more tires. If one system was really better, wouldn't every tire manufacturer's research have pushed them into a similar (generic) tire design. I'm not talking about specialty or use specific tires but general purpose stock car tires for use on roads where speed limits are 60-70 mph.

This stuff really does make a difference that can be measured, and when taken to extremes, can be easily felt. At one extreme are the low rolling resistance tires on the Honda Insight which some people have replaced because they want better, more secure feeling, handling. At the other extreme (or near it) are the tires on exotics which often last only 5000 miles, but have phenomenal grip. But for ordinary every day driving, the standard tires that you can mount any which way, and directionals are a great compromise: and you are right, research has pushed most manufacturers toward similar designs. (Although there are legitimate flavor differences, ranging from sporty touring tires to 60,000 mile tires, to 40,000 mile tires, etc.)

It's hard to pick a precise figure, but I'd guess that (within a tire type, i.e., directional, asymmetric, etc) 60% of tread design (the pattern you see) is styling, and 40% is function.

You really have to watch your "reputable" tire guy and anybody else who does work for you. I wanted a new tire for my travel trailer and was very specific to ask for a radial tire to match the other three. Guess what I got from a prominent national tire and battery vendor in my area? A flippin' bias ply tire!! I received a 205/75D15 and after checking the tire vendor's website because I was suspicious about its looks, I really wanted the 205/75R15. Subtle difference that eluded the Einstein's working at that place including the manager. At any rate, like Reagan used to say, trust, but verify.

Long Tread!! teehee. I didnt have time to read it all. It was probably already mentioned. But a lot of tire makes are directional. My first guess is if you see inside on the outside tirewall that tire is on the wrong side of your car. The directional geometries on tires are for water displacement. Having those tires installed the wrong way probably won't become apparent until you hit a puddle of water or drive through a heavy rain or snow(maybe).

Edit: My first guess is if you see 'inside' on the outside of the tirewall that the tire is mounted the wrong way on the rim.

Should tires be replaced in pairs (front pairs or rear pairs that is)? Absolutley, sort of.

Unless each side has a tire of matching size, tread pattern, manufacture and relativley same amount of wear, the vehicle will almost always pull to one side, increasing the wear rate on the other tires and requiring a constant loading of the steering components just to keep in track. The cheap fix, use matching tires.

Yes, your tire guy screwed up. They are definately directional tires. If you run them in the opposite direction the layers in the tire may actually slip or come apart. It is best that you have them fix their mistake. Not only can it tear the tire up but when you drive in the rain, it is going to channel water under your tires instead of getting rid of it. It will probably hydroplane really bad because of this.

I believe that you are totally wrong in your last comment.

Tires for running in one direction have an arrow on both sides showing the run direction. This is usually to make sure that the rainwater gets "pumped" to the outside edges.

The tires he has are marked "inside" and "outside".......probably (guessing) because they are re-enforced for pavement edges and curbs on the "OUTSIDE", but that is only a guess....but you cannot mount them all on a car with "outside" out and have them all turning in the same direction!!!

Think about it!!!

Hi Andy:

Tires marked "inside" and "outside" are asymmetrical for performance reasons, rather than more pragmatic reasons, like curb scuff resistance. Here's a bit of trivia you can use to make eyes glaze over at cocktail parties: You probably remember Michelin X tires as being the first radials. The Michelin XAS was brought out in 1965 and was the first asymmetric radial. It was produced for high-performance cars, and offered excellent handling for its day. Cornering loads are highly asymmetric, thus asymmetric tires. I posted a couple pics above of directional and asymmetric treads.

Classic Ads: Pirelli Tyres with Professor Stanley Unwin - YouTube

Unless you get tires that are specifically manufactured for the left or right side of your vehicle, you will likely have one or more tire(s) that have tread going contrary to the other tires. This said, your reputable tire guy did the right thing by putting all of the treads running in the same direction.

Perhaps Fuzion HRI tires do come in left and/or right treads in which case you may have purchased 4 of the right treads and 0 left.