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New tyre tread depths changes? - brum

I raised this issue a few weeks ago but no one seemed interested. I measured some new Michelin Crossclimate tyres as having only 7mm tread instead of the 8mm I expected all new passenger tyres to have. Michelin confirmed in writing that crossclimates have only between (iirc) 6.7 to 7.0mm of tread new.

Now Ive bought 2 brand new Conti Premium contact 2 tyres for another car for its MOT and was surprised to see them report them at only 7mm. I confirmed that reading, with even less near the edges.

Both sets were XL rated.

Am I losing my mind? Im sure the last set of the same brand/model/size of tyre I bought a few years back started at 8mm.

Continental are lobbying to have the minimum legal tread depth increased to 4mm, Michelin very sensibly are against any change citing no proof from accident stats. If Conti got their way then legally we would have to change our tyres at least twice as frequently as is now the case. Great for business, really bad for the environment and the consumer.

New tyre tread depths changes? - Bolt

I actually cannot see the logic of Michelin, apart from materials used to make the tyre last longer/possibly?, tyre tread depth will make a difference to the amount of water that the tyre is able to remove from the road to grip.

So why not increase min depth of tread, apart from costing us more the safety side IMO is of benefit, I`m with Continental

New tyre tread depths changes? - brum

This is not intended to be a discussion about the merits of the minimum depth of tread. What I am questioning is why new tyres are appearring with only 7mm of tread instead of what I thought is the standard 8mm.

Call me cynical but this is like reducing the size of a mars bar and hoping people dont notice.

New tyre tread depths changes? - Falkirk Bairn

8.00mm tread, disposed at 1.6mm = 6.44mm rubber to be word with use

6.7mm tread (michelin) disposed at 1.6mm = 5.1mm rubber to be worn with use

(5.1/6.4)x100 = 80% ie 20% less rubber = 20% fewer miles per tyre?

A big difference - almost 5 renewals 0f 6.7 mm tyres required instead of 4 renewals of 8mm tyres.

New tyre tread depths changes? - brum

Not just michelin but as I pointed out the continental now has only 7mm when new.

New tyre tread depths changes? - JonestHon

Replaced the back set on our 2010 Yaris last week.

The new budget pair is branded 'Kormran' and using my standard tyre gauge and measuring twice, the depth showing is 7.9mm.

New tyre tread depths changes? - Engineer Andy

8.00mm tread, disposed at 1.6mm = 6.44mm rubber to be word with use

6.7mm tread (michelin) disposed at 1.6mm = 5.1mm rubber to be worn with use

(5.1/6.4)x100 = 80% ie 20% less rubber = 20% fewer miles per tyre?

A big difference - almost 5 renewals 0f 6.7 mm tyres required instead of 4 renewals of 8mm tyres.

You're assuming the Michellin tyres last the same as either they used to or of competitors. One of the reasons I bought CC+s was because reviews, including user reviews said that they lasted a good bit longer than tyres of comparable performance, and testing showed they performed better when worn than competitors.

I suspect that the lesser tread depth means they can produce them cheaper - whether Michelin pass that saving onto customers is another thing. They normally are amongst the most expensive tyres comparing them on a like-for-like basis.

I should note that the move to lower starting tread depths is not new - my previous set of Dunlops were 7mm when new, as were my old Micra's last set (2003 ish) - Bridgestone RE720s (lovely tyres).

Higher tread depth tyres tended to be all season or winter tyres than were softer and wore quicker as a result (especially the all season tyres) when used outside of the coldest weather. Modern all season tyres are much better on that score, especially with those 'summer biased' ones like the CC+ and Bridgestone equivalents available. Even those like the GYs are still quite decent on wear compared to the previous generation.

I used to change out tyres at around 6 years old, start to crack, got noisy or when their wet weather performance or noise started to get a bit hairy. I'm now likely to do the same with my CC+s but stretch the timesframe (whatever comes first) to 9-10 years, as that is what seems to be what Michelin are sort-of recommending as the lifespan of their newest long-lasting tyres.

We'll see how they do - I normally replace on age as I rarely do over 9k miles per year, and mostly under 5k.

New tyre tread depths changes? - Bolt

This is not intended to be a discussion about the merits of the minimum depth of tread. What I am questioning is why new tyres are appearring with only 7mm of tread instead of what I thought is the standard 8mm.

Call me cynical but this is like reducing the size of a mars bar and hoping people dont notice.

I think you mean getting value for money, I have never checked a new tyre to see how deep the tread is, I only go on condition and correct tyre pressures.

as they are the only thing between you and the road the last thing I worry about is how much usefull tread I`m getting, when they wear to approx 2-3mm I replace no matter their mileage! not that you have a choice

New tyre tread depths changes? - gordonbennet

I suspect the two premium makes mentioned have reduced the new tread depth to stay at the top of the tyre comparison reports/articles, re tread squirm depleting that all important handling score.

I don't buy either Mich or Conti, not better enough for the price IMHO and knocking another mm off the tread isn't going to help persuade me nor anyone else if they can be bothered to check...actually i like Nokian for this clever trick, they have tread depth sipes cut into the tread at various points, as they wear so the current depth appears, all tyres should have this feature IMO.

The Hankooks i put on the Landcruiser last year came with just under 13mm tread, i can measure barely any wear in almost 2 years of commute and other use.

Edited by gordonbennet on 20/10/2016 at 22:14

New tyre tread depths changes? - Brit_in_Germany

If you buy your Crossclimates expecting them to count as winter tyres for your continental skiing holiday, in Austria you may be in for a bit of a shock then. There, there is a minimum tread depth of 4 mm to count as a winter tyre, so you only have 3 mm of wear available.

New tyre tread depths changes? - simm228

New Continentals down to 6mm, scandal

New tyre tread depths changes? - Cyd

Very interesting Brum. I've recently bought new Goodyear EfficientGrips in two different sizes, Goodyear F1s and Uniroyal Rainsport 3s. All measured 8mm new, according to my measuring stick.

New tyre tread depths changes? - Engineer Andy

I remember my Bridgestones on both my cars were 7mm to start with, as were my Mazda3's current set of Dunlop SP Sport FastResponse tyres, bought 4 years ago. Its not as though these are really low profile tyres, just relatively standard 205/55 R16s.

Maybe they are higher tread depth on higher profile tyres or older designed ones, or as some say, it could be a 'handling thing' for the tyre tests - manufacturers do like to promote their 'rubber band' tyres these days, presumably thinking everyone who buys car tyres is an 18yo chav in a pimped-up supermini, and not middle-aged people with a bad back who wants to get to work without slipping a disc driving over a small defect in the road.

New tyre tread depths changes? - GolfR_Caravelle_S-Max

I've put £480 CrossClimate+ 215/60 R16 99V XL All Season / snow & winter tyres on a 2 tonne 2007 2.5t S-Max

They have done almost 10,000 miles and hardly worn down - see below.

Tread measured using a gauge.

  • NSR 7mm
  • OSR 7mm
  • NSF 6mm
  • OSF 6mm

This week, I have driven in deep snow up and down hills with no problems!

I would buy them again.

r.ebay.com/qgNfYb

New tyre tread depths changes? - HGV ~ P Valentine

Depends on the make, anything less then 7 and I would consider using another brand of tyre. but they are usually 7 or more if brand new.

Bt I know high profile tyres are showing less grip but they reckon to have more then your standard tyre, reckon you need advice from a tyre technician if you are not one yourself or call the tyre manfacturers themselves and ask them direct.

Edited by 30 yr's a Professional Driver on 03/03/2018 at 13:51

New tyre tread depths changes? A big fat ripoof - Bilbo1234

I recently bought new continentals that were only 6.5mm. Its a ripoff and they will never see my business again. The last new tyres I checked were 9mm a few years back.

New tyre tread depths changes? A big fat ripoof - Terry W

Tyre companies make their money from selling tyres - so reducing the life (by stealth) 20% to increase sales is understandable but not commendable business practice.

The cost of tyres for a normal car (high performace etc aside) really is quite trivial.

On an average mileage (say 12k pa) a tyre will last typically 2-3 years.

A full set of michelins may cost ~ £400. The annual cost is £130-200. By reducing new tyre tread depth the cost increases by 20% (£30-40 pa)

Against the costs of fuel for a similar mileage of ~ £1200 pa, or depreciation on a small new car £2-300k pa it is below the radar.

New tyre tread depths changes? A big fat ripoof - edlithgow

Against the costs of fuel for a similar mileage of ~ £1200 pa, or depreciation on a small new car £2-300k pa it is below the radar.

It'd be a great big Death Star stylee blip on my radar screen, but then I don't have those other costs you mention.

Don't buy new tyres either, so I can't make assumptions on tread depth at the time of purchase and have to measure it.

Sounds like that'd be a worthwhile thing to do new too.

New tyre tread depths changes? A big fat ripoof - Bolt

Don't buy new tyres either, so I can't make assumptions on tread depth at the time of purchase and have to measure it.

I buy a new set about 18m- 2yr so I cant be bothered to check what I get, Civic gets through more fronts than backs and had the geometry checked in case I knocked suspension out, but its perfect so assume its just the way Civics are

I`m on my 5th Civic now and they have all been the same, though at the moment I have 1.4 so will wait and see how good this is on tyres, Bloke I bought it from put 4 different tyres on so had to change them, but he was really good on servicing, full dealer servicing but terrible on replacing tyres ?

New tyre tread depths changes? A big fat ripoof - dan86

I`m on my 5th Civic now and they have all been the same, though at the moment I have 1.4 so will wait and see how good this is on tyres, Bloke I bought it from put 4 different tyres on so had to change them, but he was really good on servicing, full dealer servicing but terrible on replacing tyres ?

Some people will spend a fortune on a car and like you say even the servicing of a vehicle but will neglect the only part of the car with contact with the road surface. I personally try and keep the tyre on each axel the same and if I have to replace one due to a unrepairable puncture the one on the other side gets done as well. New tyres always go on the rear and the ones from the rear on the front.

New tyre tread depths changes? A big fat ripoof - edlithgow

FWD usually wear faster on the front. I would replace 2 at a time, moving the backs to the front as the fronts wore out, but the last set aged-out so I had to replace them all.

New tyre tread depths changes? A big fat ripoof - Andrew-T

The cost of tyres for a normal car (high performance etc aside) really is quite trivial.

You could make it sound even more trivial if you stated it in pence per mile. Like any other statistic it can be misunderstood. The fact is that as buying tyres happens only rarely it feels like a big hit, so many people try to minimise the pain by buying cheap or leaving it as late as possible. Probably the same ones that don't think twice (or even once) about the cost of filling the tank.

New tyre tread depths changes? A big fat ripoof - madf

When I bought Michelin C Climates for the Jazz they had 8mm tread new.

After 15k miles, now 6mm rear, 5.5mm front.

At £420 ish they were not cheap, but they should last 50k miles.

Not had any snow to test them, but great on muddy hills (beekeeping)

New tyre tread depths changes? A big fat ripoof - up north

The issue will be when tread wears down then they'll be as useful as summer tyres.

New tyre tread depths changes? A big fat ripoof - edlithgow

The fact is that as buying tyres happens only rarely it feels like a big hit, so many people try to minimise the pain by buying cheap or leaving it as late as possible. Probably the same ones that don't think twice (or even once) about the cost of filling the tank.

Don't see why that's at all "probable".

Surely the default assumption would be consistent cheapskate-ism, (which is certainly what I aim for)?

The fact is that, when buying tyres, you have the option of buying cheap and leaving it as late as possible. Going electric, LPG conversion, or vegetable-oil in diesels aside, you have effectively no options when filling the tank, obsess about it as you will.

New tyre tread depths changes? A big fat ripoof - Andrew-T

<< Going electric, LPG conversion, or vegetable-oil in diesels aside, you have effectively no options when filling the tank, obsess about it as you will. >>

Ed, you have ignored the possibility of not driving at all, maybe using other modes of transport or none (two feet). There are still some who adopt the now-traditional American routine of walking only from the front door to the car.

New tyre tread depths changes? A big fat ripoof - edlithgow

<< Going electric, LPG conversion, or vegetable-oil in diesels aside, you have effectively no options when filling the tank, obsess about it as you will. >>

Ed, you have ignored the possibility of not driving at all, maybe using other modes of transport or none (two feet). There are still some who adopt the now-traditional American routine of walking only from the front door to the car.

That's right.

Mostly because, when comparing tyre and fuel purchase, which is what I was doing, because it was what you were doing in the post I was responding to, it wouldn't make any sense, would it?

That might even be why you ignored it. Dunno.

As it happens I get pretty close to not driving at all, which is a persuasive reason not to buy new tyres. Low insurance, lowish tax and zero depreciation on the Skywing dull the dumbness a bit, but items with a time limited service life, like tyres, maybe batteries, and conventionally motor oil (though I ignore the time limit on that) start to look proportionately more expensive.

New tyre tread depths changes? A big fat ripoof - simm228

Just got caught on two front 19" Continental Eco 6, new tread 6mm, £170 ea, I had 2.5 on my old ones, never again.

New tyre tread depths changes? - FoxyJukebox

On almost every occasion over the last few years that I have HAD to change tyres-it was because a repair could not be safely done.

New tyre tread depths changes? - edlithgow

On almost every occasion over the last few years that I have HAD to change tyres-it was because a repair could not be safely done.

That's another of my reasons for not buying new tyres. An unrepairable puncture on a new Michelin would hurt me more than on a just-bought part-worn, and is just, or almost, as likely.

I suppose it might also be reason not to be too bothered about tread depth on new tyres, if you feel you are likely to bust rather than wear them out. That was my impression when I did more miles and wasn't at all conscious of tyre age.

Now, my tyres are likely to age-out instead.

New tyre tread depths changes? - skidpan

Tyres are a minor motoring expense compared to all your other costs so why risk your life (and that of others) fitting used tyres that you probably have no idea why they were discarded by the previous user.

Take my Superb. Its currently on Michelins but should I ever need to buy replacements (unlikely unless I get an irreparable puncture) I would go on line and check current deals on known brands - today the Goodyear Efficient Grip Performance would win at £86.

A set of 4 would cost about £400 all in and based on my experience with the previous Superb if rotated front to back annually would last about 40,000 miles for the set, for me that would be 5 years.

Over those 5 years I would spend £1500 on insurance, £750 on RFL, £4000 on fuel, £1000 on servicing, total £7250. Then there is the depreciation, that is likely to be over £20000 over 5 years taking the total to over £27000.

As I said, tyres are cheap.

New tyre tread depths changes? - edlithgow

"Tyres are a minor motoring expense compared to all your other costs so why risk your life (and that of others) fitting used tyres that you probably have no idea why they were discarded by the previous user."

Well, one reason would be that for me they are probably the safest option, because I'm unlikely to throw away tyres with usable tread. This means that if I bought new tyres, they might last long enough to become dangerously old.

Reprehensible, I daresay, but I know myself well enough to see the danger.

"Over those 5 years I would spend £1500 on insurance, £750 on RFL, £4000 on fuel, £1000 on servicing, total £7250."

Yeh? Well, I wouldn't.

"Then there is the depreciation..."

No. There isn't

New tyre tread depths changes? - Bolt

On almost every occasion over the last few years that I have HAD to change tyres-it was because a repair could not be safely done.

Ive had same thing last few years although had reasonable wear out of my tyres, if it wasn't a screw went through tread edge it was a 6 inch roof nail, last thing was a philips screwdriver nov last year so know what you mean

Too many untidy tradesmen round my way !

New tyre tread depths changes? - Terry W

50 years ago when I got my first car remoulds were the order of the day - along with breakers yards for spare parts, diy servicing, cheap 20-50 oil etc. Even drilled out the carburetter air correction jets and mixed paraffin with 4 star to make it go further on a tank.

So I can understand why some need to save money to stay mobile.

I am still somewhat careful with money (skinflint). But one thing I will not economise on now are decent tyres. They are the only thing that keeps you in contact with the road rather than a hedge. I also change them at about 3mm tread, particularly if autumn/winter is approaching.

New tyre tread depths changes? - Andrew-T

... one thing I will not economise on now are decent tyres. They are the only thing that keeps you in contact with the road rather than a hedge.

While this statement is unarguable, it has become a bit of a mantra, as if to justify any replacement of tyres. Anyone with a healthy bank balance may happily shrug off £400 or more for a new set, but a bangernomics aficionado comparing that with the value of the car gets a different perspective.

If one's driving habits or the prevailing conditions are a priority in deciding when to replace tyres, fine. Presumably tyres become steadily less 'safe' as they wear from new. An arbitrary depth of 1.6mm (at one time 1mm) has been chosen as a compromise which I am happy to accept, as I am not a mad driver and I drive very little after dark or in freezing conditions.

New tyre tread depths changes? - skidpan

"Over those 5 years I would spend £1500 on insurance, £750 on RFL, £4000 on fuel, £1000 on servicing, total £7250."

Yeh? Well, I wouldn't.

In the UK those costs are unavoidable.

£300 a year is what I pay, many pay more. pay nothing and it will cost you far more, possibly even your liberty.

£150 a year is the norm for RFL, pay nothing and it will cost you far more.

If you do about 8000 miles a year @50 mpg it will cost you about £800. There is no way to avoid that unless you choose to fill up and not pay which will eventually lead to the loss of your liberty.

Servicing is purely optional but in reality not wise but your choice.

Driving on tyres that have limited grip due to age or lack of tread is not really clever either. Tyres that may have hidden damage is not clever either. Have an accident which is attributed to faulty tyres and its possibly a custodial sentence.

Since you live in a 3rd world country it may be acceptable to have lower standards with little or no legal deterrents but I prefer to have higher standards. I accept that many scroats live to your rules over here but that does not mean its acceptable.

Edited by skidpan on 14/12/2020 at 14:50

New tyre tread depths changes? - edlithgow

Well, as you gracelessly acknowledge, I'm not in the UK

But when I was in the UK, I managed to (legally) avoid a lot of those costs, by not being you.

There's a lot of that about.

No servicing, because DIY, and no depreciation, because bangers. Not so much petrol (which here is close to US prices) because low mileage. Low insurance, because 3PFF

In Taiwan, be it ever so Third Worldy, this is more difficult because no one else does it, and they disapprove of it perhaps more than you do. Cars must be new and shiny to avoid unbearable shame, and mechanical cluelessness rules.

To be fair though, if a sense of smug superiority triggers a knee-jerk assumption of multiple illegality and associated name-calling in the Taiwanese, I'm not aware of it, but then I don't know the Chinese for scroat.

I'm the only staffer asked to produce my registration documents to get a parking permit, which I suppose is a mild form of the same thing, but given the prevailing mechanical cluelessness that's understandable. It is, after all, the worst looking car I've seen in Taiwan, outside of the aboriginal villages. Old ladies come up and shake their heads at it.

I rather like that.

Part-worn tyres are overpriced here and if both are worn out they probably work out more expensive than new ones. I believe in the UK a lot of them come from Germany, which mandates that they be replaced as a full set, inevitably producing a supply of part worns. This, and the level of competition (Taiwanese in general don't buy anything used), seems to make them a better deal in the UK than they are here.

Edited by edlithgow on 15/12/2020 at 00:18

New tyre tread depths changes? - edlithgow

Presumably tyres become steadily less 'safe' as they wear from new.

A questionable assumption.

DRY performance (braking and handling) is inversely related to tread depth, as the "squirm" comments above hint. In the UK, with its unpredictable but fairly uniformly distributed pattern of light rain, it would be hard to predict the net effect of tread depth on safety. Probably need some fairly sophisticated sums.

In Taiwan, OTOH, with a reliable dry season and rainy season wetness concentrated in a few sustained multi-day downpours, it seems quite likely that baldish tyres are statistically safer.

This would be especially true for me since I hardly ever need to drive, so can avoid adverse conditions, and I have relatively narrow tyres, less subject to aquaplaning than "modern" wide rubber.

This ignores the effect of rubber ageing. Older tyres are thought to be less safe, but unpredictably so. IIRC, studies on tread depth effect have often excluded ageing as a variable by shaving the tyres.

Edited by edlithgow on 14/12/2020 at 15:08

New tyre tread depths changes? - KB.

Is edithgow having a bit of a larf here?:

Just being a bit provocative and awkward?

And what is 'driving in Taiwan on baldish tyres' going to add to any sensible debate?

New tyre tread depths changes? - edlithgow

Is edithgow having a bit of a larf here?:

Just being a bit provocative and awkward?

And what is 'driving in Taiwan on baldish tyres' going to add to any sensible debate?

Depends what you want to debate about. I gather it isn't 'driving in Taiwan on baldish tyres'

What then, is your post going to add to any sensible debate?

Generally, an argument that conflicts with received opinion is not met with "sensible debate".

Its met with name calling.

See above.

New tyre tread depths changes? - industryman

There are advantages to reduced tread depth on new tyres.

As mentioned above, better handling and grip on dry roads.

Lower rolling resistance (= improved fuel efficiency).

Lower drive-by noise.

The latter two feature on the label attached to new tyres, hence giving perceived advantages to the tyre buyer/tyre dealer selling the tyre.

New tyre tread depths in the 6 to 7mm region will not affect wet grip except in extreme conditions where aquaplaning could be expected.

New tyre tread depths changes? - RT

There are advantages to reduced tread depth on new tyres.

As mentioned above, better handling and grip on dry roads.

Lower rolling resistance (= improved fuel efficiency).

Lower drive-by noise.

The latter two feature on the label attached to new tyres, hence giving perceived advantages to the tyre buyer/tyre dealer selling the tyre.

New tyre tread depths in the 6 to 7mm region will not affect wet grip except in extreme conditions where aquaplaning could be expected.

Since tread depths below 3mm make aquaplaning more likely, the reduction in new depth makes the value much lower for those who change tyres at 3mm

New tyre tread depths changes? - edlithgow

There are advantages to reduced tread depth on new tyres.

As mentioned above, better handling and grip on dry roads.

Lower rolling resistance (= improved fuel efficiency).

Lower drive-by noise.

The latter two feature on the label attached to new tyres, hence giving perceived advantages to the tyre buyer/tyre dealer selling the tyre.

New tyre tread depths in the 6 to 7mm region will not affect wet grip except in extreme conditions where aquaplaning could be expected.

Since tread depths below 3mm make aquaplaning more likely, the reduction in new depth makes the value much lower for those who change tyres at 3mm

Several of those people have said they don't care to compromise on performance merely to save money, so for them thin rubber would have cachet.

Prestige tyres are thinner tyres. Market them like After Eight Mints.

Or condoms

New tyre tread depths changes? - Brit_in_Germany

If (and it may be a very big IF) the rubber compounds are more resistant to wear than the older compounds I guess the reduction in original tread depth could be justified in that the tyres have the same working life.

There was also some bleatings by Michelin a couple of years ago that the "modern" tread patterns do not suffer from lack of grip at low tread depths compared with the older patterns. Not sure I believe that one though.

New tyre tread depths changes? - galileo

If (and it may be a very big IF) the rubber compounds are more resistant to wear than the older compounds I guess the reduction in original tread depth could be justified in that the tyres have the same working life.

There was also some bleatings by Michelin a couple of years ago that the "modern" tread patterns do not suffer from lack of grip at low tread depths compared with the older patterns. Not sure I believe that one though.

To quote Mandy Rice-Davis, "they would say that,wouldn't they?"

New tyre tread depths changes? - alan1302

If (and it may be a very big IF) the rubber compounds are more resistant to wear than the older compounds I guess the reduction in original tread depth could be justified in that the tyres have the same working life.

There was also some bleatings by Michelin a couple of years ago that the "modern" tread patterns do not suffer from lack of grip at low tread depths compared with the older patterns. Not sure I believe that one though.

To quote Mandy Rice-Davis, "they would say that,wouldn't they?"

You would have thought they would not say it as it prevents people buying newer tyres from them...

New tyre tread depths changes? - Andrew-T

If (and it may be a very big IF) the rubber compounds are more resistant to wear than the older compounds I guess the reduction in original tread depth could be justified in that the tyres have the same working life.

Hmmm. As a simple rule of thumb, Grip is a consequence of Friction, and Friction usually leads to Wear. So in simple terms, long-lasting rubber doesn't usually come with the best grip. Rubber techies have been looking for a holy grail to get round that for a long time.

New tyre tread depths changes? - Bolt

If (and it may be a very big IF) the rubber compounds are more resistant to wear than the older compounds I guess the reduction in original tread depth could be justified in that the tyres have the same working life.

There was also some bleatings by Michelin a couple of years ago that the "modern" tread patterns do not suffer from lack of grip at low tread depths compared with the older patterns. Not sure I believe that one though.

iirc they also said there was a compromise in grip due to the harder rubber making for less rolling resistance, giving better fuel economy, which would account for the longer lasting tyre-depending on use.... don`t like the idea of less grip though

New tyre tread depths changes? - edlithgow

If (and it may be a very big IF) the rubber compounds are more resistant to wear than the older compounds I guess the reduction in original tread depth could be justified in that the tyres have the same working life.

There was also some bleatings by Michelin a couple of years ago that the "modern" tread patterns do not suffer from lack of grip at low tread depths compared with the older patterns. Not sure I believe that one though.

iirc they also said there was a compromise in grip due to the harder rubber making for less rolling resistance, giving better fuel economy, which would account for the longer lasting tyre-depending on use.... don`t like the idea of less grip though

Well, this is likely to be another "unacceptable factiod" but the compound on the surface of bald tyres, which is supposed to be internal and isn't supposed to contact the road surface, is softer...so...another reason for bald tyres having better grip in the dry.

I really should get some.

New tyre tread depths changes? - Bolt

If (and it may be a very big IF) the rubber compounds are more resistant to wear than the older compounds I guess the reduction in original tread depth could be justified in that the tyres have the same working life.

There was also some bleatings by Michelin a couple of years ago that the "modern" tread patterns do not suffer from lack of grip at low tread depths compared with the older patterns. Not sure I believe that one though.

iirc they also said there was a compromise in grip due to the harder rubber making for less rolling resistance, giving better fuel economy, which would account for the longer lasting tyre-depending on use.... don`t like the idea of less grip though

Well, this is likely to be another "unacceptable factiod" but the compound on the surface of bald tyres, which is supposed to be internal and isn't supposed to contact the road surface, is softer...so...another reason for bald tyres having better grip in the dry.

I really should get some.

That depends on if you intend driving in the rain, not that you mentioned it.

New tyre tread depths changes? - skidpan

Well, this is likely to be another "unacceptable factiod" but the compound on the surface of bald tyres, which is supposed to be internal and isn't supposed to contact the road surface, is softer...so...another reason for bald tyres having better grip in the dry.

As far as I am aware only Bridgestone used that type of technology (they called it dual compound) from the late 90's for about 10 years but they have abandoned it now.

The 2 tyres that I know for a fact that were made like that were the absolutely magic RE720 and the S02. They were both very popular in racing where tyres from the MSA List 1A were required since when they were shaved to about 4mm the tyres were instantly down to softer rubber and had incredible grip in the dry compared to any other road tyre available. But when they were down to under 2mm (the dry grip was even better) the wet grip was just as bad as other tyres.

The S02 was replaced by the S03 and with no dual compound the grip was much reduced.

From 1991 to 1995 I had 3 sets of RE720's on the Caterham and there was nothing better.

New tyre tread depths changes? - edlithgow

Thanks for the info on that specific technology, which I'd vaguely heard of but didn't know details.

Was the rationale that it would compensate for rubber ageing, so you'd get closer to steady-state performance as the tyre wore slowly in normal use?

I meant more generally though, because I've been plausibly told all tyres have soft compound on the inside. In combination with the lack of tread, which increases the contact surface, this gives bald tyres better performance in the dry.

As I noted earlier, I don't have to worry much about wet weather. If I wasn't so lazy and irresponsible I'd try and get some.

I dunno how much more likely they are to suffer catastrophic failure (and I'd bet no one else does either) but they will wear quickly, so i'd be changing them often, and I don't seem to be as good with the tyre irons as I used to be.

Plus the rational argument that they are actually safer is not likely to be any more appealing to Taiwans cops, should they take an interest, than it is on Internyet forums.

Edited by edlithgow on 19/12/2020 at 01:05

New tyre tread depths changes? - skidpan

Was the rationale that it would compensate for rubber ageing, so you'd get closer to steady-state performance as the tyre wore slowly in normal use?

Exactly that.

I meant more generally though, because I've been plausibly told all tyres have soft compound on the inside. In combination with the lack of tread, which increases the contact surface, this gives bald tyres better performance in the dry.

Do not confuse road tyres that are bald with slicks that are designed to have no tread. Once the rubber has worn below a certain point on slicks they will offer no grip. The ones I used many years ago had holes moulded into them over the tyre and if you went below those marks you would die, the carcass offered no grip and that will also happen with a road tyre.

New tyre tread depths changes? - edlithgow

I was basing it on this description of the rubber between groove and carcass , from a tyre expert with industry connections.

"Typically that rubber is a cool running compound - meaning it doesn't wear well. If a good wearing rubber compound were to be used, the tire would run hotter and that would hurt the long term endurance - leading to more structural failures. That would be a bad thing!"

He didn't actually say that compound was sticky. I was assuming it , based on the association between "stickiness" and rapid wear, but maybe that association isn't universal and wouldn't apply here. If I get a chance to cautiously test it and by some bizarre fluke I don't die, I'll let y'áll know.

The intuitive positive association between better dry performance and low/no tread depth is less speculative since it has experimental support, though it will never be the focus of industry funded research for obvious commercial and legal reasons.

Tire Rack Tests: An honorable exception

www.tirerack.com/tires/tests/testDisplay.jsp?&...1

"While new tires can't match the dry road handling of worn and nearly worn out tires, they do come very close to equaling their ability to stop in dry conditions".

www.theday.com/article/20160430/BIZ09/160439995

"Conversely, shallower tread can actually improve vehicle handling in dry conditions. Consumer Reports says the lower tread depth puts more of the tire in contact with the road, improving cornering as well as braking. This quality makes tread-free tires ideal for professional car racing, but not for everyday driving where you're sure to encounter wet or snowy conditions at some point."

No. I'm not.

So optimising performance for my local conditions might be statistically safer, if I could be bothered.

www.ectri.org/YRS11/Documents/Final%20website/Sess...f

80% of accidents in Finland occur in the dry. That number seems very likely to be higher in Taiwan

Low tread was over-represented in dry accidents too, which they suggest is due to an association between low tread depth and other illegal or unsafe driver behaviour.

So its complicated. Surprise!

Edited by edlithgow on 22/12/2020 at 11:21

New tyre tread depths changes? - simm228

Just bought two new Continental Premium eco 6 x 19" tyres @£170 ea, tread new, 6mm. We are being ripped off, shop around for best tread.

New tyre tread depths changes? - Andrew-T

Just bought two new Continental Premium eco 6 x 19" tyres @£170 ea, tread new, 6mm. We are being ripped off, shop around for best tread.

So why did you buy them ? :-)

New tyre tread depths changes? - badbusdriver

Just bought two new Continental Premium eco 6 x 19" tyres @£170 ea, tread new, 6mm. We are being ripped off, shop around for best tread.

6 x 19" is not a size of tyre(*). It could be a size of wheel, but unlikely as I'd expect most 19" wheels to be at least 8" wide.

(*) Not on a car anyway, possibly some kind of agricultural, military or specialist off road tyre?.

But, if you buy a car with enormous low profile tyres, you are going to pay a lot to replace them. So if this is a problem, buy a car with more a modestly sized wheel/tyre combo.

New tyre tread depths changes? - mcb100
The deeper the tread gauge (block height), the more it will squirm or distort whilst cornering, creating heat and adding to instability - particularly when initially turning into a bend. The hotter the tread runs, the faster it wears.
There has to be a trade-off point between the ability to shift water successfully and dry road handling, and maybe with improved chemistry in the compound used to construct the tyre tread, that effective sweet spot decrees that a mm or two is lost from the depth when new.
It’s a complicated science, allied to the fact that a new tyre with 6mm will roll more easily, and thus more economically, than one with 7mm.
New tyre tread depths changes? - RT
The deeper the tread gauge (block height), the more it will squirm or distort whilst cornering, creating heat and adding to instability - particularly when initially turning into a bend. The hotter the tread runs, the faster it wears. There has to be a trade-off point between the ability to shift water successfully and dry road handling, and maybe with improved chemistry in the compound used to construct the tyre tread, that effective sweet spot decrees that a mm or two is lost from the depth when new. It’s a complicated science, allied to the fact that a new tyre with 6mm will roll more easily, and thus more economically, than one with 7mm.

You're not wrong but it's further complicated by big variations in the void ratio - so tyres designed for maximum wet grip will squirm and wear more than tyres designed for maximum dry grip.

Void ratio: The amount of space between the tread block surface compared with the space taken up by the grooves (or voids) defines the void ratio.

New tyre tread depths changes? - Terry W

Tyres are a compromise - generalities:

  • hard compound = slower wear
  • soft compound = more grip
  • low tread depth = limited resistance to aquaplaning
  • deep tread depth = better rain and snow performance
  • high aspect ratio = more compliant/softer ride
  • low aspect atio = more pricise handling and steering response

This is before the complexities of tread design, tyre noise and carcase materials. There is no right answer - just a matter of priorities and choices.

Personally I will continue to pay a fairly small amount extra for better quality - in the expectation that they may help keep me from hedges and rear end collisions.

New tyre tread depths changes? - Flyboy1

New to this site but used to read Telegraph column before stopped getting news paper,

I would be very pleased with 7mm tread depth on new tyres but have just purchased a pair of rear tyres when old ones got to 2 and 2.5mm as did not want tot risk another 600mile round trip taking mum home after Xmas. Had a set of 295/35 R20 105Y POTENZA SPORT XL fitted to my car recommended by Bridgestone and various web sites as better than the older Potenza S001. The old tyres used to only have 7mm of tread depth but checking tread when home these new ones had only 5mm in centre and 4 on outer with 2 on the shoulders. That is some 30% less. This to me seems to be a rip off and wish now I had spent my £500 on pair of the older tyres which have never given any grip problems wet or dry from new until replacement. Not only am I now expecting limited mileage but also question the environmental impact. Isn't it about time tyre companies publish the tread depth? If RAC got the 3mm min depth through then these would only last few thousand miles before outers were on limits.

New tyre tread depths changes? - Xileno

Welcome to the forum. 5mm seems very mean, I recently got two new tyres and they were 7mm, down from 8mm for the last pair about three years ago. I suppose it's yet another thing we need to check when choosing tyres, make sure we get a decent amount of rubber.

New tyre tread depths changes? - badbusdriver

New to this site but used to read Telegraph column before stopped getting news paper,

I would be very pleased with 7mm tread depth on new tyres but have just purchased a pair of rear tyres when old ones got to 2 and 2.5mm as did not want tot risk another 600mile round trip taking mum home after Xmas. Had a set of 295/35 R20 105Y POTENZA SPORT XL fitted to my car recommended by Bridgestone and various web sites as better than the older Potenza S001. The old tyres used to only have 7mm of tread depth but checking tread when home these new ones had only 5mm in centre and 4 on outer with 2 on the shoulders. That is some 30% less. This to me seems to be a rip off and wish now I had spent my £500 on pair of the older tyres which have never given any grip problems wet or dry from new until replacement. Not only am I now expecting limited mileage but also question the environmental impact. Isn't it about time tyre companies publish the tread depth? If RAC got the 3mm min depth through then these would only last few thousand miles before outers were on limits.

Seems a bit strange to ask Bridgestone what kind of tyre they recommend for your car, they are not going to recommend anything other than Bridgestone are they?.

If you want an unbiased recommendation, you need to be looking at tyre reviews and tests. If doing this, it is quite possible you'd find out in advance what depth tread the tyre comes with.

New tyre tread depths changes? - mcb100
The lack of tread depth on the shoulders isn’t the disadvantage you’d initially perceive it to be.
Under normal running, the car sits on the centre portion of the tyre, where you have the deepest grooves for clearing water.
On a dry road, whilst cornering briskly and generating lateral G, the car will create body roll and, in turn, utilise the outer shoulders. Given that it’s dry (otherwise it wouldn’t create the same degree of body roll) the seeming lack of tread depth will give better steering feel, and, ultimately, grip.
From looking at a couple of reviews of this tyre, it is described as a high performance tyre and thus its longevity will be compromised by the job it has been designed to do.
New tyre tread depths changes? - thunderbird

Think its fair to say these are not tyres for a regular hatch

295/35 R20 105Y POTENZA SPORT XL

is a size for a very high performance vehicle such as a Porsche etc. These tend to come with a lower tread depth to improve the stability of the tyre in hard use. If high performance tyres were made with a full depth tread (especially on the shoulders) they would possibly overheat and then the tread would wear even faster. I have seen some tyres in the past that have very little tread depth on the shoulders when new because of this.

A search on the web quotes them as having 6.3 mm in the centre when new. Are you measuring the full tread depth or from the raised indicator?

Have you tried asking Bridgestone about this matter?

New tyre tread depths changes? - mcb100
I do think there’s considerably more to tyre design than just tread depth, and that shouldn’t be the primary consideration in selecting one tyre over another.
Has the chemical make up of the ‘rubber’ improved to such an extent that manufacturers can offer a lower tread depth, offering better handling, better fuel consumption and lower noise levels than previously?
Have CAD and millions of miles of testing in different conditions shown that a more effective tread pattern will offer better water dispersal with 6mm than older tyres with 8mm?
I’m not privy to the answers to the questions, but I’d wager that a massive company like Bridgestone probably have a shrewd idea what they’re up to when it comes to designing new tyres.
New tyre tread depths changes? - bathtub tom
I’d wager that a massive company like Bridgestone probably have a shrewd idea what they’re up to when it comes to designing new tyres.

And obtaining the maximum money from the customer.

New tyre tread depths changes? - Officina red
Hi just for information,I asked Hankook what tread depth when new was on their Ventus S1 Evo 3 K127 tyre, the reply was 6.6 mm
Edit
Had a reply from Yokohama their tyre Advan Fleva V701 has 7.5mm

Edited by Officina red on 11/01/2022 at 20:49