Tyre tread depth

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Mon 9 Jan 2017 19:10
Tyre tread depth - Doc

I have just bought two new tyres and was surprised to find the tread depth to be just under 7mm. I thought that new tyres were generally at least 8mm.

The tyres were not 'budget' but the same as the original fit: Kumho Solus KH17 165/60 R14 T (75)

Is this a new trend?

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Mon 9 Jan 2017 19:18
Tyre tread depth - Engineer Andy

Its probably more like the gauge isn't completely accurate, so 7mm is ok. Many new tyres have 'only' 7mm of tread nowadays. The last two replacement sets I've had on my cars (going back to 2005) have had 7mm deep treads.

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Tue 10 Jan 2017 10:10
Tyre tread depth - brum

I first noticed this with Michelin crossclimates and queried with Michelin. They confirmed that tread depth new could be as little as 6.5mm iirc, depending on manufacturing tolerances and 7mm was normal.

Ive since noticed a lot of the new tyres Ive bought recently are 7mm including some Conti Premium contact tyres which in the past definitely measured at 8mm.

I still see stated specs eg at Camskill, of 8mm, so it seems to me that some tyre makers are simply reducing the new depth to increase turnover. Continental are vigorously lobbying governments to increase legal minimum treads depths to 3mm as well, so their aim is to reduce tyre life by over 40% and increase sales.

Michelin has stated that there is no need to increase the minimum legal limits based on their testing and real world data from accident statistics.

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Tue 10 Jan 2017 12:42
Tyre tread depth - Brit_in_Germany

I was wondering if the EU labelling scheme might be responsible. Would a 7mm tread depth have a lower rolling resistance and/or lower noise rating than one with 8 or 9 mm?

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Tue 10 Jan 2017 12:54
Tyre tread depth - RT

I was wondering if the EU labelling scheme might be responsible. Would a 7mm tread depth have a lower rolling resistance and/or lower noise rating than one with 8 or 9 mm?

Possibly - the tread blocks move around more the deeper the tread is

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Tue 10 Jan 2017 12:55
Tyre tread depth - brum

Michelin has said that as tyres wear, their rolling resistance reduces, leading to improved fuel economy.

But I think if anything its more about increasing sales and profit.

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Tue 10 Jan 2017 14:11
Tyre tread depth - Andrew-T

Ive since noticed a lot of the new tyres Ive bought recently are 7mm including some Conti Premium contact tyres which in the past definitely measured at 8mm.

Yes they did. Looks like a barefaced way to make tyres wear out sooner. I was wondering why my present car needs a new set after 25-30K while SWMBO's old 205 Dturbo could get 50K twenty years ago.

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Tue 10 Jan 2017 14:56
Tyre tread depth - RobJP

Ive since noticed a lot of the new tyres Ive bought recently are 7mm including some Conti Premium contact tyres which in the past definitely measured at 8mm.

Yes they did. Looks like a barefaced way to make tyres wear out sooner. I was wondering why my present car needs a new set after 25-30K while SWMBO's old 205 Dturbo could get 50K twenty years ago.

The 205 Dturbo had 78 hp though, and ran on 13" wheels with 165/70 tyres. What's the current cars hp and wheel/tyre size ?

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Tue 10 Jan 2017 15:10
Tyre tread depth - skidpan

The 205 Dturbo had 78 hp though, and ran on 13" wheels with 165/70 tyres.

Agree.

Could get 50,000 out of a set of Michelins on my Escort back in the late 70's. Car had about 80 bhp and 175 70 13 tyres. They were rock hard Michelins with only 6mm on from new.

Cars are now much heavier and rubber tends to be softer to give the extra grip we have come to expect. The obvious result is more rapid wear.

Put a driver of today on a set of those Michelins from the 70's on a damp road and they would die.

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Tue 10 Jan 2017 18:15
Tyre tread depth - brum

Put a driver of today on a set of those Michelins from the 70's on a damp road and they would die.

Awaiting John F's response in 3,2,1......

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Tue 10 Jan 2017 18:36
Tyre tread depth - RobJP

Put a driver of today on a set of those Michelins from the 70's on a damp road and they would die.

Awaiting John F's response in 3,2,1......

What, you mean to say those ancient tyres - and their old-hat compounds - aren't perfectly fine ?

Some mistake, surely ...

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