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Thread: Hi and where should I look?

  1. #1
    Join Date
    Apr 2013
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    Default Hi and where should I look?

    I am new here.
    Is there an existing FAQ or Thread for Mot Tyre failure?
    I have just failed an MoT test on brake pipes and tyre.

    The tyre breadth of tread is shown in the MoT testers doc ument. (The Forum spell checker won't let me join up the two parts of the word).
    It is described as:
    The breadth of tread is the part of the tyre which can contact the road under normal conditions of use .....
    The diagram accompanying the description shows a flat tread with sharply defined "corners". It is obvious where the contact is on the diagram and the "dimension" arrows clearly start and stop at these sharp corners.

    But the tester stated the breadth of tread quite differently. And worse kept insisting that contact area is not mentioned in the guide.
    But when the Tester printed off a copy of the relevant page and gave it to me to show he was right, I could see his statements were not what I was interpreting from the description and diagram.

    Can anyone actually define what the guide phrase/description actually means when read in conjunction with the diagram?

    section 4.1 shows the breadth of tread:
    http://www.motuk.co.uk/manual_410.htm
    Last edited by andt; 05-04-2013 at 05:22 PM.

  2. #2
    Join Date
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    Grantham, Lincolnshire, England.
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    Default

    Hello,

    You didn't say whether you disagree with the tester or not so I assume you want to know for your own interest rather than in order to argue with him. Testers tend not to make such obvious mistakes as to fail a tyre that should pass as it is easily appealed against and a successful appeal to the Ministry would create a lot of trouble for the tester.

    The tyre law has changed a number of times since it was introduced and it appears the current legislation takes into account the fact that modern steering and suspension systems designed for good straight line stability and handling, the way we drive today and the design of the tyres themselves mean even tyre wear is difficult to achieve and a greater amount of wear often takes place at the shoulders of the tyre.
    It has been decided that wear at the shoulders of the tyre is not very detrimental to the performance of the tyre and as long as it shows a visible tread pattern and is without bald spots or other defects in these areas the tyre is acceptable as long as the centre portion has more than 1.6 mm of tread.

    The do***ent I have describes the centre portion as the middle three-quarters of the part normally making contact with the road. This is more clearly defined with some tyre designs than others and so assessing borderline tyres tends to be less than an exact science even after using a tape measure.

    As with a number of things on the MOT test the standing instructions from the Ministry is to let good sense be the guide and in case of doubt the tester should ask himself if he would load his wife and children into the car and take them away for a holiday. If the tester would not do this then the car or the item must fail the test.
    Whether a car with a number of borderline items should pass or fail is again a matter of discretion. I was told it is a good rule-of-thumb to use the overall impression of the condition of the car as a deciding criteria. A car that is clearly neglected and ill-maintained has an owner who is unlikely to take notice of advisory items and so the borderline items are likely to be placed on the fail side whereas a car that is clearly cared for has an owner likely to give attention to advisory items and the borderline things can be passed and advised about with relative safety.

    I hope this answers your question?

  3. #3
    Join Date
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    Default

    Quote Originally Posted by verne View Post
    Hello,

    You didn't say whether you disagree with the tester or not so I assume you want to know for your own interest rather than in order to argue with him............

    I hope this answers your question?
    Thanks for that long and considered reply.
    Unfortunately it does not address the question.
    How does the diagram and the description define "the breadth of the tread"?

  4. #4
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    It might help if I knew the reason for your question.

    Ignoring the obvious misprint in the highly simplified diagram the meaning seems clear enough when read in conjunction with the text.
    The text states the breadth of tread is that part normally in contact with the road and the diagram illustrates that part and conveniently leaves out the confusing bits at the edges that might or might not be counted as being in contact with the road depending on the design of the tyre.
    It is left up to the skill and judgement of the tester to determine what the breadth of tread is for any particular design and once he has established that he can proceed to implement the MOT regulation as per drawing.

    In conclusion and in an attempt to answer your question more accurately; the drawing doesn't exactly define the breadth of tread but rather gives information and advice to the tester in order that he can define the breadth of tread that is applicable in each instance and then apply the regulations to the part he has defined.

    Is that a satisfactory answer?

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