Should these Tyres Fail an MOT?
Discussion
Hi, would welcome the opinion of any MOT testers out there as my local garage has just failed the rears on my Boxster when they still have 3mm in all three main grooves around the whole of the tyre. As you can see from the images the tread is well above the wear indicators. They have failed the tyres because the 4th narrow outer groove is nearer 1mm but these outer grooves are not supplied as deep as the main ones and don't even have wear indicators. If the garage is correct then maybe I shouldn't be buying Bridgestone Potenzas because the outer groove is shallower to start with and loses me 2mm!! These rears have done only 6000 miles... and this is my wife's car! Interested to get your feedback! Thanks in advance. ![](https://thumbsnap.com/sc/6TRdsfDJ.jpg[/img]</a> <a href="https://thumbsnap.com/NZSDtMfq" Target="_blank" rel="nofollow">[img]https://thumbsnap.com/sc/NZSDtMfq.jpg)
Edited by Softdev137 on Friday 2nd August 16:19
Softdev137 said:
Hi, would welcome the opinion of any MOT testers out there as my local garage has just failed the rears on my Boxster when they still have 3mm in all three main grooves around the whole of the tyre. As you can see from the images the tread is well above the wear indicators. They have failed the tyres because the 4th narrow outer groove is nearer 1mm but these outer grooves are not supplied as deep as the main ones and don't even have wear indicators. If the garage is correct then maybe I shouldn't be buying Bridgestone Potenzas because the outer groove is shallower to start with and loses me 2mm!! These rears have done only 6000 miles... and this is my wife's car! Interested to get your feedback! Thanks in advance. 
Looks marginal. Central 3/4 all heeds to be 1.6mm, just to be legal. That doesn't allow for any further wear.Edited by Softdev137 on Friday 2nd August 16:19
But its not worth arguing over. Always advised at 2mm, certainly on a car that can test the grip.
henrycrun said:
Aquaplaning often ends in tears...
https://www.pistonheads.com/gassing/topic.asp?h=0&...Dogwatch said:
Bite the bulle t and get some new ones, there isn't much wear left any way and a Boxter is a lot more likely to need decent tread depth than gran's shopping trolley.
Or sell the car and get something more affordable.
Love the passive-aggresive post that implies the reason the OP doesn't want perfectly good tyres scrapped is because he is too poor to buy new tyres. Typical PH.Or sell the car and get something more affordable.
I Had this exact conversation on my 2016 STI with my local garage. I was concerned about the tyre wear but was told that certain performance tyres are designed to wear out in different areas . They are legally obliged to go with the arrow marked on the side wall of the tyre indicating where the wear indicator is. If the wear indicator is still visible then it will go through. I must admit that my Dunlop's looked like slicks in some areas but still passed MOT. hope this helps.
Looks like a pass to my eye’s
Here is the relevant section on tyre’s
5.2.3 Tyres
Size
The aspect ratio of a tyre is included in the size marking. For example, a 215/55R15 has an aspect ratio of 55%.
'Standard' car tyres have a nominal aspect ratio of 82% (unless marked otherwise) and these are almost identical in size to tyres with an aspect ratio of 80%. They can be safely mixed in any configuration on a vehicle.
Some tyres may be marked with two sizes. For example, a 185/75R14 tyre may be dual marked 185R14. In such case you can accept either marking.
Load rating – Classes 5 and 7 only
A tyre load rating table is in Appendix B.
Make sure the tyre load rating is suitable for the axle weight.
You can find the permitted maximum laden weight of an axle on the manufacturer’s plate.
If axle weights are not displayed on the manufacturer’s plate, you must assume that the load capacity of the tyres are suitable, unless there’s indisputable evidence to suggest otherwise.
If a goods vehicle has a ‘Ministry’ plate showing lower axle weights not to be exceeded in Great Britain, you must use those instead of the ones on the manufacturer’s plate.
Speed rating – Classes 5 and 7 only
A tyre's speed rating is shown on the sidewall as a letter and usually precedes or follows the load rating. Speed ratings from A to K are unacceptable, with the exception of H.
If no speed rating is shown it must be assumed that the minimum requirements are met.
Load ratings for low speed rated tyres – Class 5 vehicles only
Tyres must be suitable for use up to 70mph (L speed rating) unless the vehicle is a 'restricted speed vehicle'.
If the tyre can carry the maximum permitted axle weight of the vehicle, these vehicles can use tyres with a lower speed rating tyres up to 70mph as follows:
K speed rating – but the tyre's carrying capacity is reduced by 3%
J speed rating – but the tyre's carrying capacity is reduced by 7%
For example, K speed rating tyres can be used at 70mph if the load is reduced as follows:
146/143K = 6,000kg single or 10,900kg dual - less 3% = 5,820kg single or 10,580kg dual
You must not accept a tyre load rating that’s less than the maximum permitted axle weight.
Structure
Tyres of different types of structure, such as radial-ply and cross-ply, must not be mixed on the same axle.
Steel and fabric radial-ply tyres are considered to be the same structure.
Run flat and conventional tyres can be mixed on the same axle, although this is not recommended.
Condition and fitment
Evidence of a tyre contacting a part of the vehicle, such as due to tyre flexing or suspension movement, is not considered to be a defect. A vehicle should only be rejected if the tyre is fouling a part of the vehicle at the time of test.
Some vehicles have lock stops comprising rubbing pads on the body that the front tyres may contact on a full lock. These are acceptable if they are properly maintained so that they do not damage the tyres.
You can use a blunt instrument to open a cut in the tyre to check for exposed ply or cord as long as you do not cause further damage.
When assessing cuts in a tyre, it is permissible to check whether a cut is deep enough to reach the play or cord by using a blunt instrument to open the cut taking care not to cause further damage.
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.
When assessing lumps or bulges in a radial ply tyre, care should be taken to distinguish between normal undulations in the carcass, resulting from manufacturing, and lumps or bulges caused by structural deterioration.
Take extra care with stretched tyres because they're more prone to sidewall damage.
Recut tyres are only permitted on:
vehicles over 3,050kg ULW
goods vehicles with an ULW of at least 2,540kg having at least 16 inch (405mm) diameter wheels
passenger vehicles with an ULW of at least 2,540kg having 8 or more passenger seats
You should only accept tyres with NHS, Not for Highway Use or similar markings if they have an ‘E’ marking and a number contained within a circle. Adjacent to this circle, the sidewall must also be marked with a six digit number, which may be preceded by 75R or similar marking (see example below).
Example of a tyre marking
Direction of rotation may be indicated by an arrow and/or words, but an arrow by itself should not be taken to indicate direction of rotation.
Tread depth
A tread pattern is the combination of plain surfaces and grooves extending across the breadth of the tread and round the entire circumference. It excludes any tie-bars, tread wear indicators, or features designed to wear out substantially before the remainder of the pattern, and other minor features.
In simple terms, grooves containing tread wear indicators (TWI) or grooves cut as deep as those containing the wear indicators when new, are considered to be primary grooves. Other grooves or sipes that are not cut as deep as the primary grooves are secondary grooves and are not to be considered when assessing tread depth.
The ‘breadth of tread’ is the part of the tyre which can contact the road under normal conditions of use measured at 90 degrees to the peripheral line of the tread.
Different vehicles require different tread depths.
The following vehicles first used on or after 3 January 1933 need 1.6mm tread depth:
passenger vehicles with a maximum of 8 passenger seats, excluding the driver’s seat
goods vehicles or dual-purpose vehicles not exceeding 3,500kg DGW
tricycles with an ULW more than 410kg and all quadricycles
The primary grooves of the tread pattern must be at least 1.6mm deep within the central three-quarters of the breadth of tread and around the entire outer circumference of the tyre (see diagram 1).
Either side of the central three-quarters of the tyre can be devoid of tread (‘bald’).
Diagram 1. Primary and secondary grooves in tyre tread pattern
Diagram 1. Primary and secondary grooves in tyre tread pattern
The following vehicles must have 1.0mm tread depth:
vehicles first used before 3 January 1933
passenger vehicles with more than 8 passenger seats excluding the driver’s seat
tricycles with an ULW not exceeding 410kg with an engine capacity greater than 50cc
The tread pattern must be visible over the whole tread area (see diagram 2), and have a depth of at least 1.0mm throughout a single band of at least three-quarters over any section of the breadth of tread round the entire outer circumference of the tyre.
The 1.0mm tread depth requirement applies to the whole tread width if the original tread pattern did not extend beyond three-quarters of the tyre width when new.
Diagram 2. Tread pattern visibility
Diagram 2. Tread pattern visibility
Tyre pressure monitoring system (TPMS)
The inspection of the tyre pressure monitoring system (TPMS) is for M1 vehicles first used on or after 1 January 2012.
The TPMS warning lamp (see diagram 3) can operate in many ways depending on the vehicle type. You must only reject vehicles if it's clear that the lamp indicates a system malfunction and not simply indicating that one or more of the tyre pressures is low.
Diagram 3. Example of a TPMS warning lamp
Diagram 3. Example of a TPMS warning lamp
Defect Category
A tyre:
load capacity or speed rating not in accordance with the minimum requirements
Major
load capacity insufficient for axle presented weight
Dangerous
Tyres on the same axle or on twin wheels are different sizes
Major
Tyres on the same axle of different structure
Major
A tyre:
with a cut in excess of the requirements deep enough to reach the ply or cords
Major
with a lump, bulge or tear caused by separation or partial failure of its structure, including any lifting of the tread rubber or with cords exposed or damaged
Dangerous
Tyre tread depth not in accordance with the requirements
Dangerous
A tyre fouling a part of the vehicle
Major
A recut tyre fitted to a vehicle not permitted to be fitted with recut tyres
Major
Tyre pressure monitoring system malfunctioning or obviously not working
Major
A tyre not fitted in compliance with the manufacturer’s sidewall instructions
Major
A tyre valve seriously damaged or misaligned likely to cause sudden deflation of the tyre
Dangerous
A tyre incorrectly seated on the wheel rim
Major
Tyre obviously under-inflated
Minor
To
![](https://thumbsnap.com/sc/UeB6CTXg.png[/img]</a> <a href="https://thumbsnap.com/kfa3Gq6s" Target="_blank" rel="nofollow">[img]https://thumbsnap.com/sc/kfa3Gq6s.png)
Here is the relevant section on tyre’s
5.2.3 Tyres
Size
The aspect ratio of a tyre is included in the size marking. For example, a 215/55R15 has an aspect ratio of 55%.
'Standard' car tyres have a nominal aspect ratio of 82% (unless marked otherwise) and these are almost identical in size to tyres with an aspect ratio of 80%. They can be safely mixed in any configuration on a vehicle.
Some tyres may be marked with two sizes. For example, a 185/75R14 tyre may be dual marked 185R14. In such case you can accept either marking.
Load rating – Classes 5 and 7 only
A tyre load rating table is in Appendix B.
Make sure the tyre load rating is suitable for the axle weight.
You can find the permitted maximum laden weight of an axle on the manufacturer’s plate.
If axle weights are not displayed on the manufacturer’s plate, you must assume that the load capacity of the tyres are suitable, unless there’s indisputable evidence to suggest otherwise.
If a goods vehicle has a ‘Ministry’ plate showing lower axle weights not to be exceeded in Great Britain, you must use those instead of the ones on the manufacturer’s plate.
Speed rating – Classes 5 and 7 only
A tyre's speed rating is shown on the sidewall as a letter and usually precedes or follows the load rating. Speed ratings from A to K are unacceptable, with the exception of H.
If no speed rating is shown it must be assumed that the minimum requirements are met.
Load ratings for low speed rated tyres – Class 5 vehicles only
Tyres must be suitable for use up to 70mph (L speed rating) unless the vehicle is a 'restricted speed vehicle'.
If the tyre can carry the maximum permitted axle weight of the vehicle, these vehicles can use tyres with a lower speed rating tyres up to 70mph as follows:
K speed rating – but the tyre's carrying capacity is reduced by 3%
J speed rating – but the tyre's carrying capacity is reduced by 7%
For example, K speed rating tyres can be used at 70mph if the load is reduced as follows:
146/143K = 6,000kg single or 10,900kg dual - less 3% = 5,820kg single or 10,580kg dual
You must not accept a tyre load rating that’s less than the maximum permitted axle weight.
Structure
Tyres of different types of structure, such as radial-ply and cross-ply, must not be mixed on the same axle.
Steel and fabric radial-ply tyres are considered to be the same structure.
Run flat and conventional tyres can be mixed on the same axle, although this is not recommended.
Condition and fitment
Evidence of a tyre contacting a part of the vehicle, such as due to tyre flexing or suspension movement, is not considered to be a defect. A vehicle should only be rejected if the tyre is fouling a part of the vehicle at the time of test.
Some vehicles have lock stops comprising rubbing pads on the body that the front tyres may contact on a full lock. These are acceptable if they are properly maintained so that they do not damage the tyres.
You can use a blunt instrument to open a cut in the tyre to check for exposed ply or cord as long as you do not cause further damage.
When assessing cuts in a tyre, it is permissible to check whether a cut is deep enough to reach the play or cord by using a blunt instrument to open the cut taking care not to cause further damage.
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.
When assessing lumps or bulges in a radial ply tyre, care should be taken to distinguish between normal undulations in the carcass, resulting from manufacturing, and lumps or bulges caused by structural deterioration.
Take extra care with stretched tyres because they're more prone to sidewall damage.
Recut tyres are only permitted on:
vehicles over 3,050kg ULW
goods vehicles with an ULW of at least 2,540kg having at least 16 inch (405mm) diameter wheels
passenger vehicles with an ULW of at least 2,540kg having 8 or more passenger seats
You should only accept tyres with NHS, Not for Highway Use or similar markings if they have an ‘E’ marking and a number contained within a circle. Adjacent to this circle, the sidewall must also be marked with a six digit number, which may be preceded by 75R or similar marking (see example below).
Example of a tyre marking
Direction of rotation may be indicated by an arrow and/or words, but an arrow by itself should not be taken to indicate direction of rotation.
Tread depth
A tread pattern is the combination of plain surfaces and grooves extending across the breadth of the tread and round the entire circumference. It excludes any tie-bars, tread wear indicators, or features designed to wear out substantially before the remainder of the pattern, and other minor features.
In simple terms, grooves containing tread wear indicators (TWI) or grooves cut as deep as those containing the wear indicators when new, are considered to be primary grooves. Other grooves or sipes that are not cut as deep as the primary grooves are secondary grooves and are not to be considered when assessing tread depth.
The ‘breadth of tread’ is the part of the tyre which can contact the road under normal conditions of use measured at 90 degrees to the peripheral line of the tread.
Different vehicles require different tread depths.
The following vehicles first used on or after 3 January 1933 need 1.6mm tread depth:
passenger vehicles with a maximum of 8 passenger seats, excluding the driver’s seat
goods vehicles or dual-purpose vehicles not exceeding 3,500kg DGW
tricycles with an ULW more than 410kg and all quadricycles
The primary grooves of the tread pattern must be at least 1.6mm deep within the central three-quarters of the breadth of tread and around the entire outer circumference of the tyre (see diagram 1).
Either side of the central three-quarters of the tyre can be devoid of tread (‘bald’).
Diagram 1. Primary and secondary grooves in tyre tread pattern
Diagram 1. Primary and secondary grooves in tyre tread pattern
The following vehicles must have 1.0mm tread depth:
vehicles first used before 3 January 1933
passenger vehicles with more than 8 passenger seats excluding the driver’s seat
tricycles with an ULW not exceeding 410kg with an engine capacity greater than 50cc
The tread pattern must be visible over the whole tread area (see diagram 2), and have a depth of at least 1.0mm throughout a single band of at least three-quarters over any section of the breadth of tread round the entire outer circumference of the tyre.
The 1.0mm tread depth requirement applies to the whole tread width if the original tread pattern did not extend beyond three-quarters of the tyre width when new.
Diagram 2. Tread pattern visibility
Diagram 2. Tread pattern visibility
Tyre pressure monitoring system (TPMS)
The inspection of the tyre pressure monitoring system (TPMS) is for M1 vehicles first used on or after 1 January 2012.
The TPMS warning lamp (see diagram 3) can operate in many ways depending on the vehicle type. You must only reject vehicles if it's clear that the lamp indicates a system malfunction and not simply indicating that one or more of the tyre pressures is low.
Diagram 3. Example of a TPMS warning lamp
Diagram 3. Example of a TPMS warning lamp
Defect Category
A tyre:
load capacity or speed rating not in accordance with the minimum requirements
Major
load capacity insufficient for axle presented weight
Dangerous
Tyres on the same axle or on twin wheels are different sizes
Major
Tyres on the same axle of different structure
Major
A tyre:
with a cut in excess of the requirements deep enough to reach the ply or cords
Major
with a lump, bulge or tear caused by separation or partial failure of its structure, including any lifting of the tread rubber or with cords exposed or damaged
Dangerous
Tyre tread depth not in accordance with the requirements
Dangerous
A tyre fouling a part of the vehicle
Major
A recut tyre fitted to a vehicle not permitted to be fitted with recut tyres
Major
Tyre pressure monitoring system malfunctioning or obviously not working
Major
A tyre not fitted in compliance with the manufacturer’s sidewall instructions
Major
A tyre valve seriously damaged or misaligned likely to cause sudden deflation of the tyre
Dangerous
A tyre incorrectly seated on the wheel rim
Major
Tyre obviously under-inflated
Minor
To
Edited by Reciprocating mass on Friday 2nd August 20:18
Yep they're not primary grooves, should only be an advisory IMO. Point the garage at the DVSA guidance here: https://mattersoftesting.blog.gov.uk/getting-into-... or you can appeal the test result with DVSA directly.
Edit to add: Just re-read the start of your post and should clarify I'm not an MoT tester, although have worked for DVSA in an unrelated capacity
Edit to add: Just re-read the start of your post and should clarify I'm not an MoT tester, although have worked for DVSA in an unrelated capacity
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