Odd tyres

EFLImpudence

EFLImpudence

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I have just noticed something I have never seen before.

The tyres on my vehicle have "OUTSIDE" embossed on one side but the tread is not symmetrical so this results in it being reversed when on the 'other' side.

1694004907256.png


I can understand a tyre tread being such that the tyre must only rotate in one direction so cannot be reversed but this just seems to me to result in the tread being purposely reversed hence it is entirely pointless so why bother - if not actually undesirable.

Am I missing something?
 
They are not directional, they are asymmetric. Roughly, the inside 75% of the tyre is used for clearing water which results in the spray coming up under the wing making visibility better for other road users on the motorway in wet conditions. The outer 25% is made of slightly tougher rubber that doesn’t wear as much when cornering. Water clearance is the same on those tyres whatever side they are fitted on.
 
Not sure if I've quite got the gist of this, but if it's any help the old method of rotating tyres all round in order to even the wear was superseded by 'rotate front & rear on the same side' ever since radial ply tyres became a common fitment.

That way the 'outside' will remain so.
 
norseman said:
Not sure if I've quite got the gist of this, but if it's any help the old method of rotating tyres all round in order to even the wear was superseded by 'rotate front & rear on the same side' ever since radial ply tyres became a common fitment.

That way the 'outside' will remain so.
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That was my point and query.

Whichever way they are rotated the outside will remain outside but the tread/tyre will go round the other way.

This picture from the link above shows this very well:

1694039960320.png


If it doesn't matter which way the tread goes round then why is it not just a straight tread at 90º to the edge?
 
EFLImpudence said:
If it doesn't matter which way the tread goes round then why is it not just a straight tread at 90º to the edge?
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Straight tread at 90º is already patented by someone else. So, the manufacturer has to come up with a different tread layout.
 
EFLImpudence said:
That was my point and query.
Whichever way they are rotated the outside will remain outside but the tread/tyre will go round the other way.
Click to expand...
:unsure: not if they have just been swapped front to rear, which is the point I was making.

Sorry, I shouldn't have used the term rotated.
 
norseman said:
:unsure: not if they have just been swapped front to rear, which is the point I was making.
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What if the OP's front and rear are different widths?

The OP is concerned about the effect of the tread pattern on the rotational direction of the tyre. He's not trying to rotate the tyres for wear leveling. The question is does the pattern need to be symmetrical on the left and right. At the moment it isn't. The conclusion should be that the patterns doesn't matter. Anyone who used 2 or 3 different tyre models on the car at the same time will have an inkling of this.
 
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I don't think it will make a lot of difference. If the manufacturer wanted them only rotating in a certain direction, they'd mark it on the sidewall. Many tyres are "rotational", and usually give a small water dispersal or traction benefit when rotating in their specified direction - so you can't swap them to the other side of the car, only the other end.

Asymmetric tyres may or may not also be "rotational". As has been said, they usually work best on sportier cars with a fair bit of negative camber. The inside half has a more open tread pattern for better water dispersal. The outside has bigger, stiffer tread blocks and less open area, but in a straight line, because of the camber, wouldn't normally be running with much of the weight of the car on them. During hard cornering, the car will roll a bit, and the tyres will become more upright to the road, so that more of the footprint is on the road. The outer tread blocks will then do more of the cornering work and the car will feel a bit more reassuring when pushed hard into a bend, because the larger tread blocks won't deform as much. It doesn't matter about that side off the tyre having worse water dispersal properties, because in the wet, you wouldn't usually be able to generate that level of body roll anyway, so it wouldn't be running on the larger blocks so much.

Sometimes, the "directional" quality of the tyre isn't to do with water dispersal but other features of the tyre's construction. One tyre manufacturer told me that on the tyre I was asking about, it was more to do with the way the reinforcement weave was wound round the carcass. Under hard braking, the way the cords were wrapped, it would try to "tighten" the weave, whereas heavy braking in reverse, would loosen it.

Tyre tread | Continental tyres

There are different types of tire tread patterns which are specialized in specific driving needs like wet braking, dry handling and others.
www.continental-tyres.co.uk www.continental-tyres.co.uk
 
Avocet said:
I don't think it will make a lot of difference. If the manufacturer wanted them only rotating in a certain direction, they'd mark it on the sidewall.
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...and they do - on rotational tyres; not asymmetric tyres.

Avocet said:
Many tyres are "rotational", and usually give a small water dispersal or traction benefit when rotating in their specified direction - so you can't swap them to the other side of the car, only the other end.
Click to expand...
You can if you turn them on the wheel.

Avocet said:
Asymmetric tyres may or may not also be "rotational".
Click to expand...
How do you work that out if they have inside and outside printed on them?

Avocet said:
As has been said, they usually work best on sportier cars with a fair bit of negative camber. The inside half has a more open tread pattern for better water dispersal. The outside has bigger, stiffer tread blocks and less open area, but in a straight line, because of the camber, wouldn't normally be running with much of the weight of the car on them. During hard cornering, the car will roll a bit, and the tyres will become more upright to the road, so that more of the footprint is on the road. The outer tread blocks will then do more of the cornering work and the car will feel a bit more reassuring when pushed hard into a bend, because the larger tread blocks won't deform as much. It doesn't matter about that side off the tyre having worse water dispersal properties, because in the wet, you wouldn't usually be able to generate that level of body roll anyway, so it wouldn't be running on the larger blocks so much.
Click to expand...
That does not address the matter of the tread rotating in the other direction.

Avocet said:
Sometimes, the "directional" quality of the tyre isn't to do with water dispersal but other features of the tyre's construction. One tyre manufacturer told me that on the tyre I was asking about, it was more to do with the way the reinforcement weave was wound round the carcass. Under hard braking, the way the cords were wrapped, it would try to "tighten" the weave, whereas heavy braking in reverse, would loosen it.
Click to expand...
Therefore rotating in the other direction is not desirable.


I think this article explains it best and seems to agree with what I am thinking:

www.kwik-fit.com

Tyre Tread: what's the difference between asymmetric and directional tyres?

www.kwik-fit.com www.kwik-fit.com

"Directional Tread pattern
Directional tyres will usually exhibit an arrowhead-like tread pattern which provides a very striking appearance. But there is more to directional tyres than just appealing looks. There is an obvious compromise when designing a tyre that works just as well rotating in either direction. Asymmetric tyres do just that and in some respects this limits their performance. Directional tyres are designed to rotate in a single direction and as a result they provide excellent wet weather performance and good directional stability. Because directional tyres offer excellent traction, they also perform well on snow covered roads. That’s why many winter tyres have directional tread patterns.

Whereas asymmetrical tyres can be fitted on either side of the vehicle, directional tyres can only be rotated vertically (i.e. from front to back) otherwise the tread pattern will rotate in the wrong direction when mounted on a wheel on the other side of the car. An arrow printed on the tyre sidewall will show the required direction of travel which will also match the arrowhead shaped tread pattern."
 
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