MOT tyre requirements - David Horn
[Names changed to protect the innocent...]

Local ***** dealer invited me to bring my 2001 ****** in to have the throttle body replaced (recall item due to sticking, apparently). Got a phone call today saying the work was done, went a bit like this:

Dealer: "Do you know that one of your tyres is illegal?"

Me: "Well, I knew it was getting low, but didn't think it was that bad..."

Dealer: "Ah, but it is, Sir. Down to 2mm on the edges and nothing on the crown. Bit dodgy, y'know?"

Me: "Really? You gave it an MOT last week and said it was fine - even though I queried the tyre. It's not even on the list of advisories."

Dealer: "Uhhh...."

Suffice to say I got a new tyre at a bit of a discount, and the new throttle body seems to have done wonders to the low end performance, so I'm not complaining. So kudos to the dealer for spotting that it needed doing, even on a 7 year old car, but I'm a bit surprised that the tyres aren't an issue.

Does the MOT check that the tyres are up to the legal minimum, or simply that they're black, round, and attached to the car?

{Dropped the word 'Honda' from the subject header, as this discussion relates to all cars, and not one specific make - DD}

Edited by Dynamic Dave on 04/12/2007 at 12:21

MOT tyre requirements - Dynamic Dave
Does the MOT check that the tyres are up to the legal minimum or simply
that they're black round and attached to the car?


www.motuk.co.uk/manual_410.htm

.
MOT tyre requirements - Pugugly {P}
1. 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
Note: Each side of the central band of the tyre can be devoid of tread (ie. ?bald?) and still meet the pass.

I seem to think that the pre-EU regs were far more stringent and that "Our" regs were downgraded to match the rest of the EU.
MOT tyre requirements - Cliff Pope
So 3/4 of the breadth of the tread must have 1.6mm, and also the entire outer circumference. How wide is the outer circumference - about 1/8 of the breadth?
That doesn't leave a lot than is permitted to be "bald"?
MOT tyre requirements - Group B
So 3/4 of the breadth of the tread must have 1.6mm and also the entire
outer circumference. How wide is the outer circumference - about 1/8 of the breadth?



Its says 'around' the entire outer circumference, so it means the central 3/4 must have 1.6mm tread, you cannot have a bald patch within the central 3/4 of the breadth. But the outer 1/8ths of the breadth can be bald, so for a 205 tyre you can have one inch (25mm) bald around the circumference.

I'm surprised you are allowed to have any totally bald bits. With no sipes on the outer edges of tyres, how are they supposed to shift water and not aquaplane?

Edited by Rich 9-3 on 04/12/2007 at 11:37

MOT tyre requirements - Bill Payer
So 3/4 of the breadth of the tread must have 1.6mm and also the entire
outer circumference. How wide is the outer circumference - about 1/8 of the breadth?


I was confused when I read that too - but I think perhaps we're both confusing "outer circumference" with "outer edge"?

I *think* the word "outer" is un-necessary - the regs mean that there must be tread around the whole cirumference - no bald spots.


My Merc had a advisory on its MOT when the NSF tyre is bald on it's outer edge - most Mercs wear there tyres like that. The rest of tyre has 3-4mm on it.
MOT tyre requirements - Cliff Pope
It's certainly confusing. It says the centre 3/4 must have 1.6 mm "and also the entire outer circumference". Not "whose entire (outer) circumference".
So what is the significance of "and", "also" and "outer" ?
MOT tyre requirements - Group B
I agree its badly worded isn't it.

for a 205 tyre you can have one inch bald around the circumference.


I should have said, "for a 205 tyre you can have one inch width of bald tread around the outer edges".

My car wears its tyres unevenly too, personally I have taken 1.6mm as a minimum on any part of the tread, not allowing any part to go bald.
Dunlop SP Sport 9000 tyres have shallower tread on the edges than in the middle. This 'outer edge' description for the MoT partly explains why these tyres are like this, but I still think its silly of Dunlop to do this.

;o)

Edited by Rich 9-3 on 04/12/2007 at 13:30

MOT tyre requirements - rustbucket
I have always found the wording re tyre treads very open to debate and very much to the descretion of the Police man about to hand you a ticket.So I always get tyres changed when any of the tread is down to 2mm.So there is no argument. It has always ammazed me that HGV 's are allowed 1mm tyre tread.
--
rustbucket (the original)
MOT tyre requirements - Bill Payer
Dunlop SP Sport 9000 tyres have shallower tread on the edges than in the middle.


Most tyres do - the grooves gradually disappear as the tread runs into the sidewall. So at some point there's always going to be 0 tread depth, even when they tyre is brand new.
MOT tyre requirements - Group B
Most tyres do - the grooves gradually disappear


On SP Sport 9000s there is a definite step (not gradual reduction) in the depth of the grooves between the outer tread blocks, so the outer 30mm (or 25?) of the tread has less tread depth than the middle section. I assume this is to make the outer tread blocks stiffer for better cornering performance?

This would work okay to MoT specs if your car wears its tyres evenly; but my car also wears the edges quicker, so the tyres needed changing sooner than they would have if the tread depth was constant across the width.

;o)
MOT tyre requirements - Bill Payer
This would work okay to MoT specs if your car wears its tyres evenly;


Most cars wear the edges of the fronts quicker, but Merc's are noted for it, and for wearing the centres of the rears. I run the fronts slighter higher pressure and the rears slightly lower (I'm talking about a couple of lbs) in an attempt to help even the wear out a bit.