Full Version: Do Different Mechanics Read Tread Depth Differently?
Ie one mechanic read your tread depth as 'amber' whilst another on another day read it as 'green'?
[quote name='posing' post='972912' date='Feb 15 2010, 10:38 AM']Ie one mechanic read your tread depth as 'amber' whilst another on another day read it as 'green'?[/quote]
Hehehe, all sorts of fun with this.
As I recall minimum tread depth law is "there should be a minimum tread depth of 1.6mm. It must be measured across the central 3/4 of the tyre".
When I had a BMW, the technicians would measure the "outer" edge, right at the very edge of the tyre. So far outside the central 3/4. This always seemed to be quite low (probably due to camber and geometry setup), but not illegal, though I suspect designed to worry you into changing tyres early.
My local toyota dealership has a nice helpful sign in reception which conveniently ommits the central 3/4 part. Cynically I think this is another ploy to get more people to change earlier.
The above is my view relative to the law. If you/I feel the law is too lax, then obviously the interpretation above may be different.
Hehehe, all sorts of fun with this.
As I recall minimum tread depth law is "there should be a minimum tread depth of 1.6mm. It must be measured across the central 3/4 of the tyre".
When I had a BMW, the technicians would measure the "outer" edge, right at the very edge of the tyre. So far outside the central 3/4. This always seemed to be quite low (probably due to camber and geometry setup), but not illegal, though I suspect designed to worry you into changing tyres early.
My local toyota dealership has a nice helpful sign in reception which conveniently ommits the central 3/4 part. Cynically I think this is another ploy to get more people to change earlier.
The above is my view relative to the law. If you/I feel the law is too lax, then obviously the interpretation above may be different.
The law is what it is.. a law, it doesn't mean that because a tyre is legal it is safe. The minimum legal requirement is, as stated above, 1.6mm over the central 3/4 of the tread.
As a tyre fitter/manager I will tell my costomers the legal rquirement, if their tyre is still within the boundaries of the law I will advice them as such, but if the outer or inner edge of the tyre has little or no visible tread (by little I mean bearly visible.. not down to 1mm or so) I will point out that it is that part of the tyre that gives grip during cornering ( which is why it wears out quicker.. assuming geometry is ok) and with it having no tread, grip during cornering will be limited.
The hope is that the costomer will make the correct descision on whether or not they should change the tyre in the interest of, not only their own safety, but that of other road users and pedestrians. As tyre fitters I personally feel we have to think of other road users as well as the costomer concerned when it comes to giving out good and proper advice, ultimately it is down to the costomer to make his/her own descision.
It is unfortunate that there are some people who will want a sale no matter what the condition of the tyre is, mostly because they have monthly targets to meet or the fitter has their bonus to make up, I have had many costomers come to me for a 2nd opinion and I often tell them that their tyres have well over half the tread still on them, in some cases their tyres are almost as new. It is for this reason that I will show the costomer how to check their tyres themselves, I will advise them to buy a digital tyre pressure gauge (about a tenner fron Halfords) rather than depend on a gauge in a petrol stationj forecourt.
Do different mechanics read the tread depth differently?
Quite possibly, but not always an innocent mistake, as I said the law is the law, it is clear and simple and I don't see how it can be interpretated differently all being fair and well.
The best thing you can do is learn to check them yourself.. hopefull this guide will help you do that.
[url="http://www.videojug.com/film/how-to-check-your-cars-tyre-wear"]http://www.videojug.com/film/how-to-check-...-cars-tyre-wear[/url]
As a tyre fitter/manager I will tell my costomers the legal rquirement, if their tyre is still within the boundaries of the law I will advice them as such, but if the outer or inner edge of the tyre has little or no visible tread (by little I mean bearly visible.. not down to 1mm or so) I will point out that it is that part of the tyre that gives grip during cornering ( which is why it wears out quicker.. assuming geometry is ok) and with it having no tread, grip during cornering will be limited.
The hope is that the costomer will make the correct descision on whether or not they should change the tyre in the interest of, not only their own safety, but that of other road users and pedestrians. As tyre fitters I personally feel we have to think of other road users as well as the costomer concerned when it comes to giving out good and proper advice, ultimately it is down to the costomer to make his/her own descision.
It is unfortunate that there are some people who will want a sale no matter what the condition of the tyre is, mostly because they have monthly targets to meet or the fitter has their bonus to make up, I have had many costomers come to me for a 2nd opinion and I often tell them that their tyres have well over half the tread still on them, in some cases their tyres are almost as new. It is for this reason that I will show the costomer how to check their tyres themselves, I will advise them to buy a digital tyre pressure gauge (about a tenner fron Halfords) rather than depend on a gauge in a petrol stationj forecourt.
Do different mechanics read the tread depth differently?
Quite possibly, but not always an innocent mistake, as I said the law is the law, it is clear and simple and I don't see how it can be interpretated differently all being fair and well.
The best thing you can do is learn to check them yourself.. hopefull this guide will help you do that.
[url="http://www.videojug.com/film/how-to-check-your-cars-tyre-wear"]http://www.videojug.com/film/how-to-check-...-cars-tyre-wear[/url]
the visual safety report from my Toyota service has measurements across the tyre - inner, middle & outer.
[quote name='Heidfirst' post='973308' date='Feb 15 2010, 11:51 PM']the visual safety report from my Toyota service has measurements across the tyre - inner, middle & outer.[/quote]
Yep, and this is where in my opinion the discussion lies. Where is "inner" measured and where is "outer" measured. If different technicians do these in different places, then different results are likely.
Yep, and this is where in my opinion the discussion lies. Where is "inner" measured and where is "outer" measured. If different technicians do these in different places, then different results are likely.
On one MOT I had the tyre was wearing on an outside edge so I asked the tester whether he would pass it or I could put the spare on for the test (until I went to the tyre fitters I use). He said he would pass it.
When the test was finished he had failed that tyre for wear, and even put that the steel bands were showing!
When I queried this he unfortunately couldn't show me where the tyre was that worn down, but, by then, the test had been plugged into the computerised system.
I said I could put the spare on immediately and he could resend the MOT test, but he said I would have to rebook the test a couple of weeks later.
I must have caught him on a bad day?
When the test was finished he had failed that tyre for wear, and even put that the steel bands were showing!
When I queried this he unfortunately couldn't show me where the tyre was that worn down, but, by then, the test had been plugged into the computerised system.
I said I could put the spare on immediately and he could resend the MOT test, but he said I would have to rebook the test a couple of weeks later.
I must have caught him on a bad day?
[quote name='cootuk' post='973465' date='Feb 16 2010, 01:00 PM']On one MOT I had the tyre was wearing on an outside edge so I asked the tester whether he would pass it or I could put the spare on for the test (until I went to the tyre fitters I use). He said he would pass it.
When the test was finished he had failed that tyre for wear, and even put that the steel bands were showing!
When I queried this he unfortunately couldn't show me where the tyre was that worn down, but, by then, the test had been plugged into the computerised system.
I said I could put the spare on immediately and he could resend the MOT test, but he said I would have to rebook the test a couple of weeks later.
I must have caught him on a bad day?[/quote]
If what you say is true then the tester was commiting fraud. Why haven't you reported the matter to VOSA??
When the test was finished he had failed that tyre for wear, and even put that the steel bands were showing!
When I queried this he unfortunately couldn't show me where the tyre was that worn down, but, by then, the test had been plugged into the computerised system.
I said I could put the spare on immediately and he could resend the MOT test, but he said I would have to rebook the test a couple of weeks later.
I must have caught him on a bad day?[/quote]
If what you say is true then the tester was commiting fraud. Why haven't you reported the matter to VOSA??
My sisters car failed its mot this week on the front offside tyre, all of the tyre was ok appart from one inch of the inside, which had worn excessively, all visible tread worn, no steel showing, but still failed.
So even though if you interprit the law as it stands it should have been legal as 3/4 of the inner tyre had more than adequate tread.
But personally I think it was the right call as far as safety goes as obviously the car was riding on the bald part of the tyre.
So even though if you interprit the law as it stands it should have been legal as 3/4 of the inner tyre had more than adequate tread.
But personally I think it was the right call as far as safety goes as obviously the car was riding on the bald part of the tyre.
Even if the tyre complies just to the minimum as specified by the law I am totally convinced the minimum requirements don't meet decent safety standards.
Independents tests have shown that once a tyre tread get to less than 3mm wet weather stopping distances increase dramatically.
The stopping distance between that of 1mm tread and 3mm is as much as 45% depending on the road surface.
Also just think if a quarter of the tyre has no tread at all (which may be legal) how much more braking efficiency is affected.
See link below for furher information
[url="http://www.rospa.com/roadsafety/advice/motorvehicles/tread_depth.htm"]http://www.rospa.com/roadsafety/advice/mot...tread_depth.htm[/url]
Independents tests have shown that once a tyre tread get to less than 3mm wet weather stopping distances increase dramatically.
The stopping distance between that of 1mm tread and 3mm is as much as 45% depending on the road surface.
Also just think if a quarter of the tyre has no tread at all (which may be legal) how much more braking efficiency is affected.
See link below for furher information
[url="http://www.rospa.com/roadsafety/advice/motorvehicles/tread_depth.htm"]http://www.rospa.com/roadsafety/advice/mot...tread_depth.htm[/url]
[quote name='cootuk' post='973465' date='Feb 16 2010, 01:00 PM']When the test was finished he had failed that tyre for wear, and even put that the steel bands were showing!
I must have caught him on a bad day?[/quote]
I wouldn't be catching him on any other day after that as I'd be taking my business elsewhere.
I must have caught him on a bad day?[/quote]
I wouldn't be catching him on any other day after that as I'd be taking my business elsewhere.
We were looking at their used cars, so he lost that sale as well as any servicing/repairs after that.
I personally just use one of those small handheld gauges for reading tyre depth rather than rely on the tyre wear indicators.
That way I can check several bits of each tyre to check for uneven wear like tracking etc.
Quite quick to do if you set it as part of your routine of checking tyre pressures.
I personally just use one of those small handheld gauges for reading tyre depth rather than rely on the tyre wear indicators.
That way I can check several bits of each tyre to check for uneven wear like tracking etc.
Quite quick to do if you set it as part of your routine of checking tyre pressures.
What would be interesting, if you are so inclined is to get your visual safety report done at the same garage and see if their tyre tread depth reading is the same over the space of a week or two. In my experience, I had a 'red' but didn't make any changes then a week later the same garage gave 'amber' (different mechanic). Now a few months later, a different garage altogether gave all 'green's. This is confusing no? I have better tread depth the more I drive!
This is the reason I posted what I posted above, learn the law, know what is safe, that way you can do it yourself and save yourself any problems. Obviously if you are unsure seek proffesional advice.
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