Using directional tyres the wrong way round

[T0MMY]

I don't mean inside out

I presume there is no particular problem with running tyres the wrong way round other than that the tread is theoretically designed to clear water better in one direction?

I mainly use the bike on clockwise tracks and whilst the right hand side of the tyre is completely bald the left hand side still has 2 or 3mm of tread on it. The whole tyre has a really lopsided profile but is still road legal and usable as it has plenty of tread in the centre still. I was thinking next season I will turn the tyres round periodically to even up the wear. Any problems with this in the dry? I can't see why there would be...
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ZX6R + CBR600RR

[Torx]

[hornetmike]

its illegal , and it stops the tread working proplery so its bad all over
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87 Honda CG 125 - 97 ER5 - SR 50 -81 Z250- 96 CBR 600 F- 94 GPX600R 88- GPX 400R- 87 GS 125 - 2006 Honda CB600F- 2003 ER5 - Honda CBF 1000 2009 - Honda CBR 600 RR 2011
Current BMW R1200GS 2010

[FerretFing]

The over-skilled mechanics at Kwik-Fit managed to put a new tyre on my car the wrong way around - they noticed the error the following year when doing the MOT - maybe they just coin-tossed on the direction when fitting?....I mean, those directional arrows are very difficult to work out so 50-50 is a decent bet in their book!

I didn't even spot it or feel any difference in the car....for a whole year

[neatbik]

I might be wrong here, but i was told that running a tyre 'backwards' is a bad idea because of the way they are made - it could cause the tyre to fail.

Like i say, i could well be wrong.

[Howling TerrorOutOfOffice]

I don't know the answer but i have seen motorcycle tyres being made and the compounds are all layered in one direction...WTF that actually means i don't know, but it remains the reason why i haven't done it to my tyres.
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[Sam_Y_93]

My mate had a tyre fitted the wrong way round on the front of his fiesta and in the wet it wouldn't stop spinning, so yes from that I would say it is a bit foolish to do so.
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[T0MMY]

I should clarify two things...

The bike just passed it's MOT today with that tyre on it...when I say it's bald at the edge, I mean like the last inch, a bit that on many bikes never even touches the ground throughout the life of the tyre unless it's crashed I think the law states 75% of the tyre needs to be legal or something.

I don't care about wet grip...the bike is mainly used for trackdays over summer, in winter I do them in the car. I also highly doubt that the incredibly meagre tread on my Metzler Racetecs makes a great deal of difference either way, and indeed, given how small the contact patch on a motorcycle tyres is, I doubt the tread has anywhere near as much effect as on a car tyre.

I'm really just interested in whether there is some inherent property of the tyres construction that makes this a bad idea on a bone dry track. I doubt it somehow as it has to be built to take strong forces in all directions no matter which way round it is.
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ZX6R + CBR600RR

[alun111]

There's a reason not to do it, and I can't remember exactly, but it's something to do with where the tread joins together. It's cut at an angle, so running the proper way the tread join is actually pushed more firmly together, where as running the tyre the opposite to intended can cause the joint to seperate!

The images on this website will help you to understand what I mean.
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[T0MMY]

But the tyre has to take both braking and acceleration forces. Given how little you can apply the rear brake on a bike the forces are probably reasonably even no? If it would get pulled apart by accelerating with it the wrong way round then surely it would also get pulled apart by braking with it the right way round?
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ZX6R + CBR600RR

[Torx]

There's no danger to use a directional tyre the wrong way round. Directional tyres are designed for better stability and better water dispersing. If you fit them the wrong way round you get the exact same effect as a non-directional tyre, so don't worry about it.
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[G]

I've often used tyres the wrong way around.

Off road it's noticable that some rear tyres are primarily designed for acceleratinh while front tyres for braking. But on road there's less of a noticeable difference.

What you do need to becareful of/keep an eye on if at the join there's anything sticking up - the tyre is made from a flat sheet cut and stuck together. So somewhere along the tyre there will be a band which is where the two ends were joined.
This is angled like so _//_ so that when the tyre is on normally, even if it started to peel up a bit, it'd be squashed together. With the reverse, if it did start to peel up, it could be ripped off more.

Never seen it happen myself personally and done it many times as well as many other people in the race paddock.

Oh and I believe the legal limit 1mm over 3/4 of the tread. Also, some tyres don't have any tread at the edges at all.

[evoboy]

Ive ran Supercorsa rears the wrong way round before to eek a tad more life out of them. Mainly sc0's when doing fast tracks as it utterly shreds the RHS.

Ive done it and it had no bad side effects. But dont hold me responsible if something does happen......please
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[Wafer_Thin_Ham]

The Racetec's carcass is bidirectional apparently, so no issues to the carcass when running them backwards, just the tread issues and the fact the tread disappearing is just one measure of wear with track tyres.
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[stinkwheel]

Some tyres are front or rear fitment and you put them on one way on the front and the other way on the rear.

From this I would deduce there is no good physical reason not to other than the wear on the tread due to the direction of the force applied (ie, mostly acceleration force on the rear, only braking force on the front).

The question is, will it pass scruitineering?
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[Wafer_Thin_Ham]

[G]

[dodgydog]

I've seen a few wrong way round when I was tyre fitting, none of the customers had noticed any difference.
I put some Conti road attacks on mine, at the time they had small arrows on the tread as well as a large arrow on the sidewall. Continental had sent out instructions at the time, that they had changed rotation of front tyres only, and that for a certain batch of tyres the arrows on the tread would be facing the wrong way, the sidewall arrow was the one to go by.
MOT man still failed it (for front tyre on wrong way round) and refused to even look at the sidewall. Jobsworth wassock that he was.

Dog
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[Kickstart]

[Walloper]

[T0MMY]

[Bezzer]

[Walloper]

[Bezzer]

[Torx]

Hahaha. No no. The idea of directional tyres is to improve them over standard tyres. By not using them in the right direction, you're not receiving the ADDITIONAL benefits.

By using them the wrong way round, they're just as effective as normal tyres. So it's not unsafe, you're just not (As above) getting the additional benefits that they offer.
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He who wants to keep his garden tidy doesn't reserve a plot for weeds.