Daveg
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Post by Daveg on Jun 2, 2012 22:30:54 GMT
I wonder what other NT's would think about this tyre presented for test I may stand to be corrected here , but I do seem to remember Stealth on the other forum writing something along the lines of; He has never seen anyone make the right decision when failing tyres as to regards the horizontal tread in a tyre as these are not testable, or words to that effect? If I got that wrong Stealth I stand to be corrected, but was sure at the time of writing to wrote something along those lines regarding tyres, which then made me think about how is the 3/4 (75%) rule justifed, as in a tyre like I posted here. Not out to upset you Stealth, just something I think I am remembering Dave Attachments:
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Post by aylesburyjock on Jun 3, 2012 12:20:10 GMT
In my opinion (also willing to be corrected) it would have to be a pass and advise, as long as the centre grooves still have 1.6mm depth. You have no way of knowing if the horizontals are cut to the same depth. Even if the remaining ones appear to be, it could just be due to uneven wear. Doubt is therefore present. My problem with this is, if I pass and advise, and upon leaving the test bay the presenter is stopped by the police, who give him three points and relieve him of sixty hard earned pounds, the next visit is going to involve unpleasantness. I don't believe the police are actually trained properly in the regulations involving tyre inspection, and even if they are, look at the difference of opinion among testers, and we sopposedly are trained for this. I think there would be problems convincing the presenter( and the cop) that just because there is a difference of opinion doesn't mean you are wrong, because that tyre does look completely illegal. Trying to search through my memory, I seem to remember that before there present system, although the legal depth of tread did not cover the whole tread, there had to actually be visible tread over the whole surface. I can't help feeling that was a much better system.
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kjb
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Post by kjb on Jun 3, 2012 14:29:45 GMT
RFR-The grooves of the tread pattern are not at least 1.6mm throughout a continuous band comprising of the central three-quarters of the breadth of tread, and around the entire outer circumference of the tyre.The tyre surely does not have 1.6mm for 3/4 of the central band???
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Daveg
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Post by Daveg on Jun 3, 2012 17:17:49 GMT
If then the horizontal grooves are not testable and the manual tells us that we must check the central 3/4's of the tyre contact area for a minimum of 1.6mm, how can you as an NT; 1/ Fail a tyre for not having a 1.6mm tread depth with the 3/4's of the breadth of tread, or 2/ Overrule the manual and pass and advise a tyre like above, which is a 165/65/13 tyre, and the centre of the tyre with the TWI's in as seen only equates to 4cm in width? 12cm's is your 75% and you have only got 4cm of it? Dave
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Post by aylesburyjock on Jun 3, 2012 18:02:15 GMT
If the centre grooves are the only ones with TWIs and the other grooves are not as deep, then the tread pattern is those two grooves. The manual states that anything shallower is not to be counted as tread pattern. by passing it you are therefore not over ruling the manual , because it tells you to inspect the tread within the centre 75% of the surface, it doesn't say the tread will take up 75%. Pass and advise. No Over ruling.
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Daveg
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Post by Daveg on Jun 3, 2012 21:15:10 GMT
For my next picture I will provide another example of the same make of tyre with good tread, and the calibrated tread guage inside the horizontal tread section showing a reading, then we will have to have another discussion Dave
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phaetonott
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Post by phaetonott on Jun 4, 2012 13:10:48 GMT
When I did my initial training my instructor told me something so outrageous I filed it away under "Don't be a pratt!" but I will try to bring it out for you here Dave.
We were looking at a bridgestone about 17565r14.
There were three grooves cut full depth running radially around the tyre, and all the cuts outside the outer ones of these was not as deep. The instructor said that this outer band of shallower grooves was not to be considered as part of the tread so as a starting point for your "central three-quartres calculation you measured the distance between these grooves (about 70mm) so only the central 53mm was measured for MOT. As the transverse treads linking the three main grooves were not cut full depth the only place you can measure is the central of the three grooves.
I was too shocked to argue at the time as I was new to testing and just assumed I had been doing it wrong for 20 years.I have never found anybody prepared to back him up since, so I went back to using my old standards.
Your tyre looks like a Michelin, Dave. If I remember correctly the side grooves on one side are cut full depth, but those on the other side are about 1.5mm shallower
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Daveg
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Post by Daveg on Jun 4, 2012 13:24:26 GMT
So if I am reading your thread correctly, you are saying that the trainer was incorrect and nobody would back him up, so you went back to your old methods, and therefore based on the example I posted are you saying that tyre should fail. Dave
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nitros44
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Post by nitros44 on Jun 4, 2012 21:27:57 GMT
The way the manual states; 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. My take on it as breadth of a tyre and tread pattern are being confused here. If the outer bands of shallower tread or stepped wear what ever we call it are not to be considered as part of the tread pattern and the central 3/4 are established from inside band to the outer,then that goes against what the manual states.These shallower bands may not be considered as part of the central 3/4,BUT are still an important part of the BREADTH. The manual states;the central three-quarters of the breadth of tread,not central 3/4 of tread pattern,they is a difference. They are tyres that have a shallower band just on one side of the tread,so if you take this away from the breadth then the central 3/4 is not going to be central is it From what i can work out is that the bands of shallower tread will still be in contact with the road under normal conditions therefore the central 3/4 will have to be established by referring to the diagram in the manual,BREADTH not PATTERN. The manual info column states; Grooves that had not been cut as deep as those containing the wear indicators when new are not to be considered as part of the tread pattern. Notice it does not say part of the breadth of tyre which is what"s used to establish the central 3/4"s as per the diagram contained in the manual. In response to Daves example, As a tester i have no information regards tyres apart from whats in the manual and in my brain,no technical data,don't know how deep treads were cut,nothing so i have to make a call on whats available to me within the scope of the test,IE another tyre else where on the car the same. Looking at the tyre in the picture on a ford ka nsf 165/65x13 radial a Michelin for augments sake, the other ones on the vehicle are dun lops ,i cant make a comparison so i have to make a decision; 1 possible 2 main grooves appear to be above 1.6mm,some evidence of the horizontal tread pattern can still be seen on the inside of the tyre and the outside part of the horizontal tread pattern appears to have remaining tread which might just scrape 1.6mm situated just within the central 3/4"s. Going back to the inner horizontal tread pattern section,i would have to say it would FAIL.The section i am interested in is the area just in side the main groove to the left which is obviously worn away any testable tread.I think i would be correct in saying that a tyre this size is not going to have grooves cut to different depths or stepped wear so i presume the grooves are all the same. The main groove and the horizontal grooves to the right has tread above the 1.6mm twi,the main groove to the left judging by and looking closely at the twi is at or below 1.6mm,there is a clear difference to be seen between both and only twi,"s;the horizontal grooves although don't appear to contain twi are still testable under the 3/4 rule. Just because a groove which is cut as deep as the main grooves but does not contain a twi does NOT mean it is not testable if it situated within the central 3/4"s. Even though this might appear against popular belief,on this discussion it was mentioned that "A" tyre (NOT BY DAVE)was shallower by 1.5mm on its outer shoulders. My response to this is; ;D Tyres; ever since i can remember that is; that grooves on the outer shoulders have always had some small difference to regards tread depth compared to the centre part of the tread from new,something to do with temperature when the tyre is in use.Such difference of a mm,they have been like that for years. Where the manuals states grooves not cut as deep as the main grooves in my opinion applies to the obvious ones that are clearly visible,ones that clearly show a step are an example,not grooves with small differences that cant be clearly seen or established.
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Daveg
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Post by Daveg on Jun 4, 2012 21:38:35 GMT
I think you should give yourself a pat on the back there Nitros , you explained that very well I thought Dave
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nitros44
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Post by nitros44 on Jun 4, 2012 21:46:06 GMT
IT only took me since 7.00pm and its now nearly 10.10pm lol
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Daveg
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Post by Daveg on Jun 4, 2012 22:05:56 GMT
IT only took me since 7.00pm and its now nearly 10.10pm lol 11400 seconds LOL ;D, what where you doing ;D Dave
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Post by baz657 on Jun 8, 2012 15:30:37 GMT
If the centre grooves are the only ones with TWIs and the other grooves are not as deep, then the tread pattern is those two grooves. The manual states that anything shallower is not to be counted as tread pattern. by passing it you are therefore not over ruling the manual , because it tells you to inspect the tread within the centre 75% of the surface, it doesn't say the tread will take up 75%. Pass and advise. No Over ruling. I was told on my last refresher that all in attendance may leave their sensible heads outside ie. the rules may be crazy but them are the rules you will test to. The grooves with TWI's are the only testable grooves - the rest are not testable. End of. Different (and more sensible) rules are applied by the police who use Construction & Use law. The only way round all these different depth of treads across the breadth is for all MOT test centres to be provided with an official database of all tyres manufactured and the different tread depths in different areas when new. Then testers will compare the tyre in front of them with the database. That would add cost and time to the test so it ain't ever gonna happen. Reason for Editing: 0/10 for spelling
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Daveg
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Post by Daveg on Jun 8, 2012 17:46:37 GMT
was told on my last refresher that all in attendance may leave their sensible heads outside ie. the rules may be crazy but them are the rules you will test to. The grooves with TWI's are the only testable grooves - the rest are not testable. End of. Different (and more sensible) rules are applied by the police who use Construction & Use law. I am not sure that different rules apply between the Police and VOSA's MOT Scheme , we do however need to use common sense but we can't pass a tyre telling the customer their cars are legal at time of mot and then expect them to accept getting 03 points per tyre on their license without some reproach against the mot scheme Modern tyres are more complicated to understand I respect that but I am sure that if the treads are not stepped we can assess 3/4 of the breadth of tread, and where the 3/4 area has stepped tread we can advise where necessary. But you can't have a law for one and another law for another , you would just being saying that the MOT is not the minimum legal standard anymore Dave
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Post by aylesburyjock on Jun 8, 2012 20:58:56 GMT
Dave, the test IS no longer a minimum safety standard test, and I'm sure you already know that. Nitros there seems to be a lot of 'I think I may remember,' and 'I presume' and such like phrases there in your post. Does this not indicate some doubt?
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Daveg
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Post by Daveg on Jun 9, 2012 15:50:41 GMT
Dave, the test IS no longer a minimum safety standard test, and I'm sure you already know that. Nitros there seems to be a lot of 'I think I may remember,' and 'I presume' and such like phrases there in your post. Does this not indicate some doubt? Jock LOL ;D you have some serious doubt about what standards to apply to the MOT Scheme at this time LOL ;D, from your very own submissions above ;D Lets have a look Can we fail a tyre with 7mm of tread remaining, well NO , so 1.6mm must be the MINIMUM standard ;D Can we fail brake pads with 14mm of pad thickness on them, well no , the MINIMUM being 1.5mm ;D Can we fail a bush or a pin with no free play present from new ;D, well no we have MINIMUM limits of about 1.5 to 2.0mm wear present before we can fail them ;D So are we still testing to minimum standards or has Jock now introduced a new higher standard to be applied ;D Dave
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Post by aylesburyjock on Jun 10, 2012 22:05:39 GMT
;D Dave, the test IS no longer a minimum safety standard test, and I'm sure you already know that. Nitros there seems to be a lot of 'I think I may remember,' and 'I presume' and such like phrases there in your post. Does this not indicate some doubt? Jock LOL ;D you have some serious doubt about what standards to apply to the MOT Scheme at this time LOL ;D, from your very own submissions above ;D Lets have a look Can we fail a tyre with 7mm of tread remaining, well NO , so 1.6mm must be the MINIMUM standard ;D Can we fail brake pads with 14mm of pad thickness on them, well no , the MINIMUM being 1.5mm ;D Can we fail a bush or a pin with no free play present from new ;D, well no we have MINIMUM limits of about 1.5 to 2.0mm wear present before we can fail them ;D So are we still testing to minimum standards or has Jock now introduced a new higher standard to be applied ;D Dave I did not introduce them Dave, Europe did. You very handily quoted lots of areas where we still test to minimum standard. Ball joint dust covers split, with no play in the joint. Steering locks. Any bells ringing yet? Anyway I better quit before we get complaints of being off topic, but there are many other examples now. Maybe you need to remind yourself what minimum means.
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Daveg
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Post by Daveg on Jun 10, 2012 22:18:48 GMT
;D Jock LOL ;D you have some serious doubt about what standards to apply to the MOT Scheme at this time LOL ;D, from your very own submissions above ;D Lets have a look Can we fail a tyre with 7mm of tread remaining, well NO , so 1.6mm must be the MINIMUM standard ;D Can we fail brake pads with 14mm of pad thickness on them, well no , the MINIMUM being 1.5mm ;D Can we fail a bush or a pin with no free play present from new ;D, well no we have MINIMUM limits of about 1.5 to 2.0mm wear present before we can fail them ;D So are we still testing to minimum standards or has Jock now introduced a new higher standard to be applied ;D Dave I did not introduce them Dave, Europe did. You very handily quoted lots of areas where we still test to minimum standard. Ball joint dust covers split, with no play in the joint. Steering locks. Any bells ringing yet? Anyway I better quit before we get complaints of being off topic, but there are many other examples now. Maybe you need to remind yourself what minimum means. No Jock I don't think I need reminding there lol , I always knew a minimum standard applied whether Europe were involved or not, and you previously said that we did not test to minimum standards , I never did , we put minimum standard rubbish back on the road lol , then the national figures look good ;D Dave
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nitros44
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Post by nitros44 on Jun 14, 2012 23:52:30 GMT
In my opinion (also willing to be corrected) it would have to be a pass and advise, as long as the centre grooves still have 1.6mm depth. You have no way of knowing if the horizontals are cut to the same depth. Even if the remaining ones appear to be, it could just be due to uneven wear. Doubt is therefore present. My problem with this is, if I pass and advise, and upon leaving the test bay the presenter is stopped by the police, who give him three points and relieve him of sixty hard earned pounds, the next visit is going to involve unpleasantness. I don't believe the police are actually trained properly in the regulations involving tyre inspection, and even if they are, look at the difference of opinion among testers, and we sopposedly are trained for this. I think there would be problems convincing the presenter( and the cop) that just because there is a difference of opinion doesn't mean you are wrong, because that tyre does look completely illegal. Trying to search through my memory, I seem to remember that before there present system, although the legal depth of tread did not cover the whole tread, there had to actually be visible tread over the whole surface. I can't help feeling that was a much better system. Well if you are willing to be corrected then;not only can i correct you ,but maybe also give you a little lesson on how to examine a tyre. Your saying you would have to pass and advise the tyre showing in Daves post. You then go on to state this;My problem with this is, if I pass and advise, and upon leaving the test bay the presenter is stopped by the police, who give him three points and relieve him of sixty hard earned pounds, the next visit is going to involve unpleasantness.
Well you are correct that you do have a problem Jock; and the problem is; if you were to pass/advise the tyre in Daves post which is clearly beyond doubt a failure. then you may want to take a look at the video contained in this post ;D In the video is a tyre which is the same type as in Daves post,but new to show the tread and its twi"s. The twi"s have been highlighted across the tread which shows 4 of them which is proof that the diagonal grooves have been cut to the same depth as the 2 main vertical grooves,on either side of the 2 main grooves,which makes them testable as part of the diagonal /sloping down from centre grooves are within the 3/4 ruling . Referring back to the worn tyre picture, as there is no remaining tread on the left(inner)of the tyre it would mean that the tyre has failed,and please Jock don't give me that crap regards stepped wear as there is non,or its impossible to tell,this is not a performance tyre,its a bog standard run of the mill common enough tyre with basic tread design that doesn't take rocket science to work out if it fails or passes,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,DOES IT ;D Attachments:
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nitros44
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Post by nitros44 on Jun 17, 2012 18:48:27 GMT
Its gone quiet ;D
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