MoT - tyre tread depth

[wemorgan]

Regarding the MoT tyre tread requirements I've read:

"The grooves of the tread pattern are not at least 1.6mm throughout a continuous band comprising

-The central three-quarters of the breadth of tread, and

-Round the entire outer circumference of the tyre"


So my question is, how does the MoT tester judge what is 75% of the tyre width? Is this just an approximate eye-ball or does he take the tyre width from the tyre sidewall markings and then measure with a ruler? Is the tyre width the same as the tread width?

I ask, as today my car faied its MoT on excessive wear on the front tyres. Both inside edges were worn, indicting that the tracking was out. I was a bit miffed as I had checked this before the MoT myself and thought them OK.

Life is too short to argue, so I will duly get them changed and the tracking sorted. But I just like to know how things should be done.

 

[BlackC55]

Sometimes they measure but most of the time they just judge for themselves. Generally any baldness fails......

 

[BTB 500]

Good question, I was wondering exactly the same thing myself! Vitos are renowned for wearing the outside edge of the front tyres, and mine is no exception. But the dealer passed the tyres today when it went in for a free 'health check'

 

[markjay]

How deep was the deepest part of the thread, if I may ask?

I would suggest that if the deepest bit is under 3mm than the tyre should go regardless.....

 

[kth286]

Regarding the MoT tyre tread requirements I've read:

"The grooves of the tread pattern are not at least 1.6mm throughout a continuous band comprising

-The central three-quarters of the breadth of tread, and

-Round the entire outer circumference of the tyre"


So my question is, how does the MoT tester judge what is 75% of the tyre width? Is this just an approximate eye-ball or does he take the tyre width from the tyre sidewall markings and then measure with a ruler? Is the tyre width the same as the tread width?

I ask, as today my car faied its MoT on excessive wear on the front tyres. Both inside edges were worn, indicting that the tracking was out. I was a bit miffed as I had checked this before the MoT myself and thought them OK.

Life is too short to argue, so I will duly get them changed and the tracking sorted. But I just like to know how things should be done.

However if the tester feels that the inside edge of tyre is nearly through to canvas and he feels it is dangerous, it does not matter how much good tread you have on the rest of tyre.

It would be the same as if you had a new tyre on car but there was a split on the inside - it would likely fail.

 

[Cen]

Speaking from an MOT point of view its the tester who makes the judgement. Its the same with brake pads requiring a minimum of 1.5mm. My wife's car failed earlier this year on the pads being less than the required thickness however, when I changed them they were over 2mm which annoyed me.

I know an MOT examiner who advised me that during a tester refresher course he gave the students a piece of paper and requested they draw two paralel lines at 1.5mm apart. He told me the results were astonishing with some having a gap of 5mm and some testers did not understand what two paralel lines were.

 

[Alps]

when i has my mot done on the C36 a few years back, the mot guy was going to fail it on the rear tyres, then he got a template out and said they passed as the balding bits were on the outside but this is the way the tyres were made from new!

 

[wemorgan]

How deep was the deepest part of the thread, if I may ask?

The central section was ~4mm

However if the tester feels that the inside edge of tyre is nearly through to canvas and he feels it is dangerous, it does not matter how much good tread you have on the rest of tyre.

The outside edge was mostly bald with a faint trace of where the tread pattern was. In my non-expert view there was still quite a few thousand miles before any risk of the canvas coming through.

The key lesson learnt for me is to be more thorough with my random tyre inspections.

 

[Will]

I can see the MOT failure side of this being a bit annoying, but by the sounds of things the tyres were well on their way to being replaced - look at it positively as a gentle 'nudge' that might have been needed to get the tyres replaced before the cold/wet weather arrives.

Might have been a blessing in disguise - could save you from an unexpected hairy moment

 

[wemorgan]

I can see the MOT failure side of this being a bit annoying, but by the sounds of things the tyres were well on their way to being replaced - look at it positively as a gentle 'nudge' that might have been needed to get the tyres replaced before the cold/wet weather arrives.

Might have been a blessing in disguise - could save you from an unexpected hairy moment

Yes those are fair points

My only real gripe is that I'm planning on getting some winter tyres in the not too distant future. So the current tyres would have stayed as they were until next Spring. But yes like you say, for the modest cost it's made the car safer than it was.

My other car also needs 2 tyres next month. So that's 8 tyres within a few weeks. Yikes.

 

[Rory]

The central section was ~4mm



The outside edge was mostly bald with a faint trace of where the tread pattern was. In my non-expert view there was still quite a few thousand miles before any risk of the canvas coming through.

The key lesson learnt for me is to be more thorough with my random tyre inspections.

They sound exactly the same as mine were when I got an advisory from an MOT at the dealership.

I do few miles so left them on and next year they didn't mention them! I changed them a bit later, but only because to the casual observer they looked bad.

I had an MOT the other day (again at the dealer) and got an advisory for a repaired windscreen chip which has been there and unmentioned on the previous 3 MOTs!

 

[BTB 500]

The dealer recorded 3-5mm tread on my Vito tyres. There's just a band on the outside edge where the tread is zero (but not down to the canvas or anywhere near IMO). As per the OP I had no idea how that 75% of tread width was defined/measured.

All 4 of my tyres are the same as I rotated front to back when I first noticed the issue. They've done over 27k miles now and I fully appreciate they will need replacing in the near future - it's just a question of whether I need to get it done in the next few days (for the MOT) or not.

Dealership in question sells & fits tyres and is an MOT station (albeit not the one it's going to), so I'm hoping all will be OK!

 

[BTB 500]

Well the Vito passed the MOT yesterday - they put an advisory about the band with no tread on each tyre but said it was fine. And this was at Kwik-Fit!

 

[Stratman]

Just be aware the bald band will only get wider and may be illegal before the next MOT.

 

[Tiff]

Some tyres are made with less tread depth on the edges of the tyre , this applies especially to commercial tyres for some reason. It is covered in the MOT manual, and no reason for failure. For minibuses the minimum tread depth is 1mm..... why? I don't know!

 

[wemorgan]

My replacement tyres from Blackcircles cost me £50/each (fitted). I wanted to have the toe angles also checked, but in the end had a full geometry alignment done for £80. So those costs plus the £65 for ARB bushes keeps the car on the road for another year. All quite reasonable costs I thought.

 

[BTB 500]

Just be aware the bald band will only get wider and may be illegal before the next MOT.

Sure, but it's a pretty slow process as they have lasted 3 years so far. The narrow band with no tread is barely in contact with the road ... it just gets scrubbed in tight turns.

 

[BTB 500]

My replacement tyres from Blackcircles cost me £50/each (fitted).

Cheapest direct replacement I could find for the Vito (Continental 225/55 R17 101H RF) was £143 a corner

 

[wemorgan]

Mine are minnows compared to yours being 175/60 R15.

But I was pleased to also find that my other car on 225/45/17 are ~£110.
Odd that my lower profiles are cheaper than yours. I wonder if it's a more common size and therefore greater competition.