At what tread depth to replace tyres?

[mawallace]

I took my car into the garage today, and at 4mm they said the tyres should be changed "for extra grip" in the winter.

now I know the legal depth is 1.8mm - and I have read 3mm as a recommened point to change.

Any thoughts of the group on here

[daz6215]

Legal is 1.6mm

[fungus]

I took my car into the garage today, and at 4mm they said the tyres should be changed "for extra grip" in the winter.

now I know the legal depth is 1.8mm - and I have read 3mm as a recommened point to change.

Any thoughts of the group on here

The IAM recommend replacing tyres at 3mm. Anything below that is getting a bit near the limit, which incidently is 1.6mm.

I remember reading an article in a magazine a couple of years ago, where they tested the braking performance of a Rover 75 in the wet, fitted with sets of tyres of differing tread depths, from new, approximately 10mm, down to the legal minimum.
I can't remember the figures, but the braking distances started to increase significantly as the tread depth dropped, especially below 3mm.

[zadocbrown]

You'll get a little more grip from a new tyre, but probably not a huge amount. I would probably leave it a while. Mechanics will be cautious because they know lots of people would drive out and not look at their tyres again for months, by which time they could be lethal.

[ExadiNigel]

This video has probably been posted before, but is quite informative...

http://www.youtube.com/watch?v=cVMqLmtOIYQ

Nigel

[martine]

This video has probably been posted before, but is quite informative...

http://www.youtube.com/watch?v=cVMqLmtOIYQ

Nigel

That brings it home then! Excellent vid.

[Angus]

Not seen that one before, makes interesting viewing. Especially as the front tyres on my van are at 2mm If only I could convince the lease company to change them

Accidentally drop a packet of nails/screws?

[Standard Dave]

I've found that garages of all kinds (dealers, independants, tyre-brake-exhaust) will tell you every time you go in that one of the pairs of your tyres is in need of replacement and that they have your size in stock can get them by this afternoon heres a quote for it I expect quite a few people get the tyres changed it's just business.

Tread depth is only of importance in the wet, snow or sleet and you need ehough tread to prevent it filling with water and causing aquaplaning, as has been mentioned I'm under the impression this is around 3mm for normal use.

There are economic and environmental reasons not to change tyres before there is a large reduction in safety or serviceability.

[TripleS]

I've found that garages of all kinds (dealers, independants, tyre-brake-exhaust) will tell you every time you go in that one of the pairs of your tyres is in need of replacement and that they have your size in stock can get them by this afternoon heres a quote for it I expect quite a few people get the tyres changed it's just business.

Tread depth is only of importance in the wet, snow or sleet and you need enough tread to prevent it filling with water and causing aquaplaning, as has been mentioned I'm under the impression this is around 3mm for normal use.

There are economic and environmental reasons not to change tyres before there is a large reduction in safety or serviceability.

I could suggest one or two minor adjustments to the wording there, but it would only be tinkering and wouldn't change anything much. It's nice to see somebody keeping a sense of proportion, Dave.

Best wishes all,
Dave.

[Angus]

Not seen that one before, makes interesting viewing. Especially as the front tyres on my van are at 2mm If only I could convince the lease company to change them

Accidentally drop a packet of nails/screws?

Usually a self tapper just on the edge does the job. Not that I would, you understand

Not for a moment was I suggesting YOU would

[MGF]

So when it is very wet the 'double your following distance' might make sense bearing in mind the vehicle in front could stop significantly quicker than you due to a difference in tyre tread depth. Obviously not much benefit of having 3mm tread if the vehicle behind only has 1.6mm

[TripleS]

So when it is very wet the 'double your following distance' might make sense bearing in mind the vehicle in front could stop significantly quicker than you due to a difference in tyre tread depth. Obviously not much benefit of having 3mm tread if the vehicle behind only has 1.6mm

I'd still try to avoid having it demonstrated that the following guy's 1.6 mm is insufficient: and we all have a pretty good idea how to do that, don't we?

Best wishes all,
Dave.

[ExadiNigel]

Not seen that one before, makes interesting viewing. Especially as the front tyres on my van are at 2mm If only I could convince the lease company to change them

Are you leasing the car directly or is the company you work for leasing the vehicle? Go into a load of spiel about your safety with lots of mention of the duty of care your employer is obliged to show towards you!

If that fails, I like the sound of the self-tapper!

[ExadiNigel]

....Company leased van. It comes down to who's paying for the tyres. They're included in the lease agreement, so the company won't pay for tyres. It was a previous manager who suggested the alternative method.

Yeah, your company is paying for the tyres so they need to ensure that the contract specifies a realistic depth for when the tyres can be replaced. The difference in tyre cost between replacement at 1.6mm vs 3mm is not a great deal if I remember correctly.

[GJD]

The difference in tyre cost between replacement at 1.6mm vs 3mm is not a great deal if I remember correctly.

Really? Assuming that a new tyre has 8mm of tread, and that the wear rate (as in mm of tread lost per mile travelled) is constant, then I make changing tyres at 3mm rather than 1.6mm to be a 28% cost increase - which I'd regard as quite a lot.

I think the first assumption is valid, if not a little conservative - 8mm is about the maximum I've measured for the tread depth of a new tyre. The second assumption may be open to challenge though.