20p Tyre Tread Test

Joe_Horner

ChumLee wrote: »

Or Tommy Asbo on his moped with 0.5mm of tread and a provisional licence pishing down with rain on the way back from his CBT.

Yeah, him too.

Colour me cynical, but I reckon the reasoning goes something like this:

Hauliers are cost conscious, so leave them with the 1mm limit that used to apply to everyone (and let them have re-cuts into the bargain).

Tommy Asbo isn't going to take any notice anyway, so let him have slicks cos he'll probably kill himself anyway.

The great middle ground of "responsible car drivers" will pay for absolutely anything "cos it's safety innit" rather than have their responsibility questioned. So let's up their limit from 1 to 1.6 and then convince them that they really need twice that. Some will even start changing at 4 or 5mm because they're getting "close to the 3mm limit".

ChumLee

Joe_Horner wrote: »

Yeah, him too.

Colour me cynical, but I reckon the reasoning goes something like this:

Hauliers are cost conscious, so leave them with the 1mm limit that used to apply to everyone (and let them have re-cuts into the bargain).

Tommy Asbo isn't going to take any notice anyway, so let him have slicks cos he'll probably kill himself anyway.

The great middle ground of "responsible car drivers" will pay for absolutely anything "cos it's safety innit" rather than have their responsibility questioned. So let's up their limit from 1 to 1.6 and then convince them that they really need twice that. Some will even start changing at 4 or 5mm because they're getting "close to the 3mm limit".

The winter tyre brigand.

sillygoose

I used to, and still do with my personal vehicle change when below 3mm.

But feel some pity for all the millions of company car drivers, the lease companies won't let you change until typically below 2mm. A car on a soaking motorway with 1.8mm tyres feels pretty alarming to drive at times.

Not me of course :whistle: but I wouldn't be surprised if the odd driver near the 2mm cutoff level finds a deserted lay-by some night and does a few burn-out and emergency stops to make sure they are low enough to qualify for a change next day...

ChumLee

sillygoose wrote: »

I used to, and still do with my personal vehicle change when below 3mm.

But feel some pity for all the millions of company car drivers, the lease companies won't let you change until typically below 2mm. A car on a soaking motorway with 1.8mm tyres feels pretty alarming to drive at times.

Not me of course :whistle: but I wouldn't be surprised if the odd driver near the 2mm cutoff level finds a deserted lay-by some night and does a few burn-out and emergency stops to make sure they are low enough to qualify for a change next day...

Probably not as alarming as a Cortina with 1.1mm of tread in 1975 but both legal.

Incidentally before we became metric what fractions of a inch were everyone debating to be unsafe but legal?

Joe_Horner

sillygoose wrote: »

But feel some pity for all the millions of company car drivers, the lease companies won't let you change until typically below 2mm.

Bear in mind that the lease companies (and their insurers) will have done the sums and found that using that extra mm before changing doesn't have any significant effect on the accident rate for the fleet despite what the various "look at your stopping distance" reports might suggest.

If there was any real, quantifiable, risk that they hadn't addressed in order to save money on tyre changes then there's a real chance that the first time someone got killed by one of their drivers because they only had 2mm of tread left they'd find themselves in court on corporate manslaughter charges.

Joe_Horner

ChumLee wrote: »

Incidentally before we became metric what fractions of a inch were everyone debating to be unsafe but legal?

Curiously enough, we weren't. Tyre checks were only added to the MOT in 1968, and the limit was defined as 1 mm from the start because we knew we were going metric by then

Before that, if it held air it was legal.

sillygoose

Joe_Horner wrote: »

Bear in mind that the lease companies (and their insurers) will have done the sums and found that using that extra mm before changing doesn't have any significant effect on the accident rate for the fleet despite what the various "look at your stopping distance" reports might suggest.

If there was any real, quantifiable, risk that they hadn't addressed in order to save money on tyre changes then there's a real chance that the first time someone got killed by one of their drivers because they only had 2mm of tread left they'd find themselves in court on corporate manslaughter charges.

No they won't. 1.6mm is the legal requirement so they are covered by that from corporate manslaughter.

The only reason they change below above 1.6mm at all is because companies wouldn't be very happy with their drivers refusing to drive illegally today because their tyre is 1.6mm and the tyre agent can't get the right size for a week to change it.

The only calculation they will have done is how tight a margin they can squeeze it down to and still get away with it.

ChumLee

Joe_Horner wrote: »

Curiously enough, we weren't. Tyre checks were only added to the MOT in 1968, and the limit was defined as 1 mm from the start because we knew we were going metric by then

Before that, if it held air it was legal.

We only went metric proper a couple of years ago when you were no longer allowed to buy a pound of spuds. Schools in the 70s still taught feet and inches.

ChumLee

sillygoose wrote: »

No they won't. 1.6mm is the legal requirement so they are covered by that from corporate manslaughter.

The only reason they change below above 1.6mm at all is because companies wouldn't be very happy with their drivers refusing to drive illegally today because their tyre is 1.6mm and the tyre agent can't get the right size for a week to change it.

The only calculation they will have done is how tight a margin they can squeeze it down to and still get away with it.

Is that illegal?

Joe_Horner

sillygoose wrote: »

No they won't. 1.6mm is the legal requirement so they are covered by that from corporate manslaughter.

The fact 1.6mm is legal doesn't give a defence in itself. Plenty of things that are perfectly legal but can lead to manslaughter charges if they lead to death from a known, or reasonably knowable, risk.

Seeing as every man and his dog is told repeatedly that the performance of tyres reduces dramatically under 3mm, a company that has a policy of using them to 2mm simply to save costs would need to be able to show that such widely known performance loss wasn't a significant factor in any subsequent fatalities. The lease companies and their insurers will have the figures to show that.