At what tread depth to replace tyres?

[ExadiNigel]

I make it about 21/22%

[GJD]

I make it about 21/22%

Depends which way round you do the sums. Someone who is used to replacing their tyres at 1.6mm then changes strategy and starts replacing them at 3mm instead would see a 28% cost increase. Someone doing the opposite - initially replacing at 3mm then changing strategy to start replacing at 1.6mm would see a 21.875% cost saving. That's the beauty of percentages .

I think the first way round is more representative of the discussion in the thread.

All still depends on my simplifying assumption of constant wear rate.

[jont]

I think the first way round is more representative of the discussion in the thread.

All still depends on my simplifying assumption of constant wear rate.

I always worked it out that a set of new tyres was less than my insurance excess...

[TripleS]

I make it about 21/22%

Depends which way round you do the sums. Someone who is used to replacing their tyres at 1.6mm then changes strategy and starts replacing them at 3mm instead would see a 28% cost increase. Someone doing the opposite - initially replacing at 3mm then changing strategy to start replacing at 1.6mm would see a 21.875% cost saving. That's the beauty of percentages .

I think the first way round is more representative of the discussion in the thread.

All still depends on my simplifying assumption of constant wear rate.

FWIW I would expect the wear rate to be greatest when the tyres are new, due to the increased flexing of the deeper tread blocks. This will concentrate the load and increase the abrasion on the edges of the tread blocks When the tread depth is more shallow they'll be likely to stay flat on the road surface. Well that's how I see it: all muddled thinking as usual.

Best wishes all,
Dave.

[ScoobyChris]

I always worked it out that a set of new tyres was less than my insurance excess...

That must be an impressive excess (or cheap tyres)

Personally, I tend to run my tyres down to the legal limt before changing them...

Chris

[TripleS]

I always worked it out that a set of new tyres was less than my insurance excess...

That must be an impressive excess (or cheap tyres)

Personally, I tend to run my tyres down to the legal limt before changing them...

Chris

Some folk might criticise you for doing that, but I wouldn't. I do the same; and I don't feel there's anything wrong with it, so long as we maintain awareness that there will be reduced grip in wet conditions, and we make the appropriate adjustments to driving style. OTOH we get better grip when it's dry, er, I think....

Best wishes all,
Dave.

[jont]

I always worked it out that a set of new tyres was less than my insurance excess...

That must be an impressive excess (or cheap tyres)

£350 excess, £250 for a set of tyres (or at least was in January when I last changed them).

[waremark]

So why is there not a more vocal campaign to increase the permitted minimum tread depth to be increased? How have the authorities decided to impose a requirement for ESP systems, but not to increase the minimum tread depth to 3 mm?

[waremark]

So why is there not a more vocal campaign to increase the permitted minimum tread depth to be increased? How have the authorities decided to impose a requirement for ESP systems, but not to increase the minimum tread depth to 3 mm?

PS Personally, my ideal is to do a track or handling day once the tyres get to 3mm, and to get value out of the rest of the tread that way.

[GJD]

£350 excess, £250 for a set of tyres (or at least was in January when I last changed them).

Is that for all four or just a pair?

I guess you probably have quite little wheels on your roller skate, so that must help .

[jont]

£350 excess, £250 for a set of tyres (or at least was in January when I last changed them).

Is that for all four or just a pair?
I guess you probably have quite little wheels on your roller skate, so that must help .

All 4. These days they certainly count as little at 15"f,16"r. £45/corner for fronts, £80 for the rears IIRC.

[fungus]

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.

What price do you place on safety?

[Gareth]

What price do you place on safety?

Think of the children!

[ScoobyChris]

What price do you place on safety?

This site makes interesting reading http://www.rospa.com/roadsafety/info/tyre_tread_depth.pdf, especially on the 2nd page where it shows the graph. Even 1 mm of tread worn away on a new tyre increases the stopping distance on smooth concrete significantly - perhaps we should all change our tyres a lot earlier than 3mm?

Chris

[jont]

Even 1 mm of tread worn away on a new tyre increases the stopping distance on smooth concrete significantly - perhaps we should all change our tyres a lot earlier than 3mm?

Or perhaps we shouldn't be using concrete for road surfaces?