DVSA updates MOT guidance on stretched tyres

Regulations are clear on tread depth, cuts and speed ratings but stretched tyres remain unclear

DVSA updates MOT guidance on stretched tyres
Are stretched tyres an MOT failure?

The DVSA has updated its guidance for MOT testers assessing stretched tyres during the annual test with new diagrams that show correctly and incorrectly seated tyres.

Regulations say that “a tyre should not be used on a road if it’s not maintained in such condition as to be fit for the use to which the vehicle is being put”.

The DVSA say this means tyres must be fitted on suitable wheels with suitable valves, giving technicians a reason to fail stretched tyres.

Rejections might include a damaged or misaligned valve stem or an incorrectly seated tyre.

The European Tyre and Rim Technical Organisation publish a standards manual with approved rim widths for all sizes of tyre.

TEST-CORRECT-copy

Example one: The tyre bead sits on the wheel rim as intended by the manufacturer. Image: DVSA.

However, if a tyre is fitted outside of this recommendation, it does not necessarily mean the tyre will be incorrectly seated on the rim.

Whether the tyre is correctly seated will also depend of the tyre make, load carrying capacity and rim design.

In example two, the wheel rim and tyre are incompatible and there is a clear gap between the tyre bead and the wheel rim because the tyre is over-stretched.

In this instance, DVSA say the vehicle should be rejected because the tyre is incorrectly seated on the wheel rim.

test-incorrect

Example two: Due to the tyre being stretched the tyre is no longer correctly seated on the wheel rim. Image: DVSA.

Where this isn’t obvious, the nominated tester should pass and advise.

Drivers could also find that they are driving with an invalidated insurance policy if they have narrow tyres fitted on wide rims.

Are you still unsure about stretched tyres? Have you seen an extreme example? Share your comments below and send any photos to [email protected].

63 Comments

  1. I think the RFR needs re thinking, as far as the customer is concerned the tyre is inflated on the rim so therefore is seated correctly or it would be flat,ie incorrectly seated. I know this seems a bit stupid maybe on my part but ask DVSA to define incorrectly seated please, not just a picture of a sidewall that is open to question.

    Reply
    • Thanks for your comment. It’s still very much a grey area isn’t it! I will indeed put you your valid query forward to the DVSA, and we’ll cover the response accordingly on GW. Regards, Mike.

      Reply
  2. I think the RFR needs re thinking, as far as the customer is concerned the tyre is inflated on the rim so therefore is seated correctly or it would be flat,ie incorrectly seated. I know this seems a bit stupid maybe on my part but ask DVSA to define incorrectly seated please, not just a picture of a sidewall that is open to question.

    Reply
    • Thanks for your comment. It’s still very much a grey area isn’t it! I will indeed put you your valid query forward to the DVSA, and we’ll cover the response accordingly on GW. Regards, Mike.

      Reply
  3. If the tyre is still inflated then surely it’s a P&A ? A bit like if a brake pipe looks very corroded but passes the brake test, the pipe is P&A ??

    Reply
    • That’s not true. Take a read of section 3.6. There are other RfRs but the main one jumping out at me is that if a brake pipe is corroded and has reduced in thickness by 1/3 then it is a RfR.

      Reply
      • But with out cutting a pipe open how can you see the wall has been reduced. By a 1/3 you cand see the internal diameter bore all the thickness of the wall been testing going on 21 years and think the manual needs to be rewritten.

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        • I think it needs to be 0.2mm less but check this out

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      • Interested to know how you measure the thickness of corrosion in a brake pipe.

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        • With the brake pipe assessment tool.
          Once you scrape off the loose corroded area, you can usually see how thin the brake pipe has become using the tool for reference. Granted i couldn’t tell you if its more than a third of the wall thickness or not, if it looks considerably thinner than a good bit of pipe then i would fail it.

          Reply
  4. If the tyre is still inflated then surely it’s a P&A ? A bit like if a brake pipe looks very corroded but passes the brake test, the pipe is P&A ??

    Reply
    • That’s not true. Take a read of section 3.6. There are other RfRs but the main one jumping out at me is that if a brake pipe is corroded and has reduced in thickness by 1/3 then it is a RfR.

      Reply
      • But with out cutting a pipe open how can you see the wall has been reduced. By a 1/3 you cand see the internal diameter bore all the thickness of the wall been testing going on 21 years and think the manual needs to be rewritten.

        Reply
        • I think it needs to be 0.2mm less but check this out

          Reply
      • Interested to know how you measure the thickness of corrosion in a brake pipe.

        Reply
        • With the brake pipe assessment tool.
          Once you scrape off the loose corroded area, you can usually see how thin the brake pipe has become using the tool for reference. Granted i couldn’t tell you if its more than a third of the wall thickness or not, if it looks considerably thinner than a good bit of pipe then i would fail it.

          Reply
  5. Some new cars with low profiles fit closer to the second picture. There needs to be a black and white statement. For example 8j wheel tyre size 225-245 etc. In this over competive market one needs to fit tyres.

    Reply
    • Exactly! I recently went to the BMW garage at Lindale in the lake district and every single new BMW in the show room had stretched tyres. This needs to be put in a black and white statement like you said that certain wheel sizes are only aloud a certain tyre size range.

      Reply
    • With this I couldn’t agree more!
      Glad we don’t have such rules in the Netherlands, but saying a certain width is to be fitted it’s all clear to the MOT tester AND the car owner. Now if the MOT tester wants to screw with you he can decline it, and you can do nothing about it, while his neighbor would grant you the MOT with the same setup.

      Reply
    • There are some guidelines on the internet regarding the minimum and the maximum your rim with can take legally. Beyond those guidelines I think its illegal.

      Reply
  6. Some new cars with low profiles fit closer to the second picture. There needs to be a black and white statement. For example 8j wheel tyre size 225-245 etc. In this over competive market one needs to fit tyres.

    Reply
    • Exactly! I recently went to the BMW garage at Lindale in the lake district and every single new BMW in the show room had stretched tyres. This needs to be put in a black and white statement like you said that certain wheel sizes are only aloud a certain tyre size range.

      Reply
    • With this I couldn’t agree more!
      Glad we don’t have such rules in the Netherlands, but saying a certain width is to be fitted it’s all clear to the MOT tester AND the car owner. Now if the MOT tester wants to screw with you he can decline it, and you can do nothing about it, while his neighbor would grant you the MOT with the same setup.

      Reply
    • There are some guidelines on the internet regarding the minimum and the maximum your rim with can take legally. Beyond those guidelines I think its illegal.

      Reply
  7. If you can see the rim that is beyond the tyre, as in the second image, common sense must prevail.

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  8. If you can see the rim that is beyond the tyre, as in the second image, common sense must prevail.

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  9. If the tyre stays inflated then it must be seated properly regardless if its stretched or not?

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  10. If the tyre stays inflated then it must be seated properly regardless if its stretched or not?

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  11. I understand the point but I have wide rims and get an appropriate tyre to fit I like more rubber on the ground with how I drive.

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  12. I understand the point but I have wide rims and get an appropriate tyre to fit I like more rubber on the ground with how I drive.

    Reply
  13. Reasonable amount of stretch is not dangerous at all, but clearer guideline about what is acceptable need to be made because people are coming under-fire for no real reason.

    Reply
  14. Reasonable amount of stretch is not dangerous at all, but clearer guideline about what is acceptable need to be made because people are coming under-fire for no real reason.

    Reply
  15. Thanks for the update, it is clear in the examples which is a pass and which is a fail. In example 2 the tyre is unsafe and could deflate on sharp cornering, no grey area just fact.

    Reply
  16. Thanks for the update, it is clear in the examples which is a pass and which is a fail. In example 2 the tyre is unsafe and could deflate on sharp cornering, no grey area just fact.

    Reply
  17. I thought the rule was amended recently to say the tyre has to be fitted on a rim in accordance with tyre manufacturer’s guidelines. Some manufacturers design tyres to allow for 15-20mm of stretch, others don’t. For example Nankang say 225 profile suitable for 7-8.5J but Avon say 8J and 8J only.

    Reply
  18. I thought the rule was amended recently to say the tyre has to be fitted on a rim in accordance with tyre manufacturer’s guidelines. Some manufacturers design tyres to allow for 15-20mm of stretch, others don’t. For example Nankang say 225 profile suitable for 7-8.5J but Avon say 8J and 8J only.

    Reply
  19. Owning the UK’s largest drift motoring school we put tyres to the test 24-7, to far more extremes to what any road driver will ever do. Even more so that most track drivers.

    A stretched tyre if beaded correctly will stay on the rim as long as any normal tyre unstretched. As long as the correct air pressure is within the said tyre…

    Reply
    • How many pot holes does your drifting circuit have?

      Reply
  20. Owning the UK’s largest drift motoring school we put tyres to the test 24-7, to far more extremes to what any road driver will ever do. Even more so that most track drivers.

    A stretched tyre if beaded correctly will stay on the rim as long as any normal tyre unstretched. As long as the correct air pressure is within the said tyre…

    Reply
    • How many pot holes does your drifting circuit have?

      Reply
    • From what i’ve seen of drifting, when cornering the tyre is spinning, thus reducing lateral load as the tyre isn’t gripping the road. That’s a VERY different scenario to cornering hard which would deform the side wall of the tyre and could result in an instant deflation in which you would rapidly accelerate to your crash scene!

      Reply
  21. Looks reasonably straight forward but maybe a guideline phrase of the tyre sidewall not being less than the extended plane formed by the outer rim outer edge. One question though, i presume the observation of the sidewall is taken where the tyre is not in contact with the ground (where the load deflects the sidewall beyond the outer rim edge)?

    Reply
  22. Looks reasonably straight forward but maybe a guideline phrase of the tyre sidewall not being less than the extended plane formed by the outer rim outer edge. One question though, i presume the observation of the sidewall is taken where the tyre is not in contact with the ground (where the load deflects the sidewall beyond the outer rim edge)?

    Reply
  23. The tyre is designed to do a specific job. When you effectively change the shape of the tyre, the tyre no longer serves it’s purpose. Side walls work in conjunction with the rim to strengthen the tyre. The forces exerted on the tyre are now compromised because the side wall is no longer efficient. This affects top speed and also stopping power.

    Reply
    • Excellent comment.

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    • Not strictly true, a tyre is only as structural as the air inside it. If you get a puncture on a so called correctly seated tyre it’s still going to fold. And as for people talking about it as if its a new untested modification, it’s been around since the hot rod days and been tried and tested on track cars. I would suggest the DVSA actually test them on a car for thousands of miles and realise they are talking pish.

      Reply
  24. The tyre is designed to do a specific job. When you effectively change the shape of the tyre, the tyre no longer serves it’s purpose. Side walls work in conjunction with the rim to strengthen the tyre. The forces exerted on the tyre are now compromised because the side wall is no longer efficient. This affects top speed and also stopping power.

    Reply
    • Excellent comment.

      Reply
    • Not strictly true, a tyre is only as structural as the air inside it. If you get a puncture on a so called correctly seated tyre it’s still going to fold. And as for people talking about it as if its a new untested modification, it’s been around since the hot rod days and been tried and tested on track cars. I would suggest the DVSA actually test them on a car for thousands of miles and realise they are talking pish.

      Reply
  25. I am glad some one has finally seen since, I have never seen, driven or hear of any thing that is so ridiculous as “stretch tyres” and “stance” with negative camber. Surely it should come under construction and use regulations? I am all for modified vehicles but some things are a mod to far.

    Reply
  26. I am glad some one has finally seen since, I have never seen, driven or hear of any thing that is so ridiculous as “stretch tyres” and “stance” with negative camber. Surely it should come under construction and use regulations? I am all for modified vehicles but some things are a mod to far.

    Reply
  27. The VeeDub boys will be crying tonight.

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  28. The VeeDub boys will be crying tonight.

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  29. How many crashes have been caused because of a stretched tyre?

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  30. How many crashes have been caused because of a stretched tyre?

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  31. I see it that the tyre bead should be in contact with the wheel rim flange. In the second picture the tyre is only (almost as the picture isn’t a very clear example) touching the wheel rim body.
    Another example of RFR, would be if the sealing edge (inner most) of the tyre was visible, ie had turned 90°.
    In both examples they can still hold air. Look at it another way. The wheel rim flange has a job to do, if the tyre doesn’t meet it, it can’t!

    Reply
  32. I see it that the tyre bead should be in contact with the wheel rim flange. In the second picture the tyre is only (almost as the picture isn’t a very clear example) touching the wheel rim body.
    Another example of RFR, would be if the sealing edge (inner most) of the tyre was visible, ie had turned 90°.
    In both examples they can still hold air. Look at it another way. The wheel rim flange has a job to do, if the tyre doesn’t meet it, it can’t!

    Reply
  33. Surely the tyre manufacturer has designed the tyre to work at its best fitted normally. They don’t design them to be stretched.??

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  34. Surely the tyre manufacturer has designed the tyre to work at its best fitted normally. They don’t design them to be stretched.??

    Reply
  35. I have had a interesting afternoon reading your comments on various subjects long may they continue, discussion is an important tool to learn with. Well I have had my own garage for some 45 years and I feel that in such a time one really does learn a lot. By the way I am not a technician bless them all, no just a mechanical engineer with the emphasis on engineer. Sorry but that word technician congers up a picture of a science lab body with a computer implant. Ok well about the tyre issue, yes certainly often we find that guidance words are conceived by many who have no or little experience but is still worth noting however. If we look at the race car, lets say formula 1 for an instance, we know how important tyres are to win lap times and weather conditions. I cannot imagine what there TECS would say to using a tyre on a rim as in figure 2 .

    Reply
  36. I have had a interesting afternoon reading your comments on various subjects long may they continue, discussion is an important tool to learn with. Well I have had my own garage for some 45 years and I feel that in such a time one really does learn a lot. By the way I am not a technician bless them all, no just a mechanical engineer with the emphasis on engineer. Sorry but that word technician congers up a picture of a science lab body with a computer implant. Ok well about the tyre issue, yes certainly often we find that guidance words are conceived by many who have no or little experience but is still worth noting however. If we look at the race car, lets say formula 1 for an instance, we know how important tyres are to win lap times and weather conditions. I cannot imagine what there TECS would say to using a tyre on a rim as in figure 2 .

    Reply
  37. If stretched tires are so good then why isn’t this absurd practice used in racing purposes? Where has common sense gone?

    Reply
  38. If stretched tires are so good then why isn’t this absurd practice used in racing purposes? Where has common sense gone?

    Reply

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