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MOT tyre failure  Rate Topic 
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 Posted: Thu Nov 4th, 2021 07:49 pm
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DB9
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Mana: 
Stealth wrote:
DB9 wrote:
That's interesting, in my experience I've always thought the colour was white or light grey. Try doing a google search for tyres-ply or cords exposed and see what colour you think!

Cut in tyre + exposed steel cord + water = rust = brown colour.

Just a thought.


But cord doesn't actually rust, its construction is a little like string if you feel it. steel plies on the other hand maybe.

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 Posted: Wed Nov 3rd, 2021 07:00 pm
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Stealth
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Mana: 
DB9 wrote:
That's interesting, in my experience I've always thought the colour was white or light grey. Try doing a google search for tyres-ply or cords exposed and see what colour you think!

Cut in tyre + exposed steel cord + water = rust = brown colour.

Just a thought.

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 Posted: Wed Nov 3rd, 2021 08:36 am
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DB9
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Mana: 
That's interesting, in my experience I've always thought the colour was white or light grey. Try doing a google search for tyres-ply or cords exposed and see what colour you think!

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 Posted: Mon Nov 1st, 2021 01:34 pm
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Carlos991
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Thank you. The statement you showed was the same I was shown today by the tester. I asked to be shown the cords and although I was still not convinced cords were visible i decided against an appeal. The .gov website I read contradicts the up to date statement which states a cut of any size can be peeled back by blunt instrument and Is a fail if cords visible. Both the tester and service manager say they can see brown cords.

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 Posted: Mon Nov 1st, 2021 10:45 am
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Stealth
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Copy & paste from the MOT Manual, which may help clarify the question ...

The following criteria should be used when assessing a cut in a tyre:

any ply or cord that can be seen without touching the tyre - fail

if by folding back rubber or opening a cut with a blunt instrument, so as not to cause further damage, exposed ply or cord can be seen irrespective of the size of the cut - fail

if a cut which is more than 25mm or 10% of the section width whichever is the greater, is opened with a blunt instrument and cords can be felt but not seen - fail

Before failing a cut, you must make sure it’s the cords that you can feel not a foreign object. If you’re not sure, then you should pass and advise.

Dificult to give a definitive answer based on a photo of the cut in question, but if ply or cord could/can be seen when the cut is opened as described above, then the size of the cut is irrelevant & the tyre would fail.

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 Posted: Sun Oct 31st, 2021 12:33 pm
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castrolrob
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Mana: 
double check the mot manual but from memory it goes along the lines of"if cords can be felt FAIL,if cords can be seen FAIL.ALL IRRELEVANT OF 25/35MM WHATEVER!but ive been wrong before of course and i cant see the pic well enuff to be able to make that call from here.of course they cud be pulling your pants down as well but read the tyre section of the inspection manual first to see if it meets the stated criteria.

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 Posted: Sat Oct 30th, 2021 08:12 pm
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DB9
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I see tyres failing all the time for profit. Pity I can't expand the photo for a more detailed closer inspection. Doesn't the manual say something like; A cut deep enough to reach the ply or cords greater than 25 mm or 10% of the sectional width!! Although the manual does also say any ply or cords exposed on its own. That tester must be able to see a pin in a tree :D

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 Posted: Sat Oct 30th, 2021 08:07 pm
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Carlos991
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I’ve since read the .gov website and the split can be 30mm without any cord showing to pass so I’m not sure why I was told the tester opened up the cut to reveal the cords. I don’t think they should do that unless cut is 25mm or 10% of width of tyre which ever is greater. My tyre is 305mm. The cut is no more than 15mm so by opening it up surely would cause more damage. I specifically asked the service manager why a small cut had failed and he mentioned it was cut to the cords. I then asked how they knew that and he replied because the cut was opened by the tester to show the cord.

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 Posted: Sat Oct 30th, 2021 07:26 pm
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Vinnie
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Mana: 
Doesn't look that bad on the photo but the tester must have had good reason to fail it. Good eyesight too.

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 Posted: Sat Oct 30th, 2021 12:00 pm
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Carlos991
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Hello. My car failed MOT today at Porsche dealership on a cut tyre. Technician says the cut is down to the wire and is a fail. I read a cut has to be greater than 25mm to fail. Not sure if this is the depth or length of cut but I’m just feeling unlucky that this cut has failed resulting in me agreeing to purchase 2 new tyres @ £700. The tyre has 4.5 / 5 mm tread. I’m going to keep the tyre to inspect the cut once I get it home on Monday. Would be interested to hear what others think. I was reluctant to take the car home today as I let the MOT expire due to family circumstances so opted to go ahead and replace tyres. Thank you.

Attachment: 4F06571D-086A-40AF-A383-E3242ED051FE.jpeg (Downloaded 67 times)

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