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Sun 28 Oct 2012 17:17

All - EU tyre labelling confusion - unthrottled

Seeing as the new tyre ratings are for rolling resistance, wet braking and noise are about to come into force, I thought I'd check out how my tyres fared. My tyres are 175/70R13T

The new Kleber came up with a pretty poor rating:

Rolling resistance: F, wet braking: C, noise 69

Fair enough, it's a cheap tyre. What about the old Michelin Energy?

Rolling resistance: E, wet braking: B, noise 68

Better, but not not great for a 'premium' price tyre.

What about other sizes. In 205/55 R16 91V the Michelin Energy scores

Rolling resistance: B, wet braking: A, noise 70

Curiouser and curiouser. Is the bigger tyre really more efficient than the smaller one, contrary to what we see in the real world? Well yes, if you test the tyre at its rated load. This is what they do. The smaller tyre is more heavily deformed under its maximum permitted load and hence has higher rolling resistence.The problem is that this you can't extrapolate this data down to the sort of loads that you normally experience while driving normally.

It's a bit like measuring fuel economy at the maximum speed a vehicle is capable of reaching! It doesn't tell you anything meanigful about how the economy of the vehicle at normal road speeds.

But this apples to oranges comparison isn't particularly helpful because of the unnecessary variable of load rating that's been thrown into the equation. Is this yet another example of EU bureaucrats wading into an area in which they know nothing, convinced that only they have the solutions to making the world a better place?

Edited by unthrottled on 28/10/2012 at 17:18

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Sun 28 Oct 2012 18:55

All - EU tyre labelling confusion - RT

I've noticed other apparent anomalies - Vredestein Quatrac 3 SUV which do well for wet grip in subjective customer tests of All-Season tyres but rates towards the bottom of comparable tyres for wet grip in the new labelling system.

I think that testing tyres at their rated load is the only way - heavier cars need tyres with higher load rating - generally customers will be comparing tyres of the same size and load rating, to fit their specific car.

Edited by RT on 28/10/2012 at 18:56

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Sun 28 Oct 2012 19:12

All - EU tyre labelling confusion - unthrottled

I think that testing tyres at their rated load is the only way

For emergency braking and speed load-yes. For fuel economy, no.There are other snags with testing at rated load: It underestimates the risk of aquaplaning.

generally customers will be comparing tyres of the same size and load rating

Up to a point. But for a given width of wheel, you can fit tyres of several different widths. If you use a class based system, you might be tempted to squeeze a 205mm tyre on to a rim aimed at a 185mm in the mistaken belief that you'll get better economy and braking because you'll switch from a 'B' to an 'A' rating.

In the same way, the most economical full size ute will still use more fuel than the least economical city car,

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Sun 28 Oct 2012 21:45

All - EU tyre labelling confusion - jamie745

Down the years our fine country has taken on the Germans twice and emerged victorious. We've sailed the seven seas, gone to all four corners and turned a quarter of the Earth pink. This fine island nation has led and changed the world so often it is not an occasion - but the norm. Great people have fought to retain the liberty of this Great Britain!

These days someone we've never voted for in Belgium can order us to put stickers on things.

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Sun 28 Oct 2012 22:07

All - EU tyre labelling confusion - RT

These days someone we've never voted for in Belgium can order us to put stickers on things.

That's because someone we collectively voted into power took the UK into the Common Market knowing how it might evolve - it's called democracy - where half the people don't bother to vote and nearly half the rest vote against it.

Edited by RT on 28/10/2012 at 22:08

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Sun 28 Oct 2012 22:14

All - EU tyre labelling confusion - jamie745

The word democracy cannot be applied to the EU because as an institution they fundamentally hate it. Nobody under the age of 56 has had a say on our membership of this and frankly nobody of any age in any country has had a say on what the EU actually does now.

Like Hitler just without the tanks.

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Mon 29 Oct 2012 09:49

All - EU tyre labelling confusion - primeradriver

Nobody under the age of 56 has had a say on our membership of this

No-one living in the North-East under the age of 1000 has had a say in our membership of 'England' -- and that rankles with me far more than membership of the EU.

This is a non-point. If you want someone to blame, blame Heath.

Edited by primeradriver on 29/10/2012 at 09:49

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Mon 29 Oct 2012 14:37

All - EU tyre labelling confusion - Roly93

The word democracy cannot be applied to the EU because as an institution they fundamentally hate it. Nobody under the age of 56 has had a say on our membership of this and frankly nobody of any age in any country has had a say on what the EU actually does now.

Like Hitler just without the tanks.

As the joke goes, Q : whats the smallest book in the world ? A: The book of EU benefiits to the UK economy.

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Tue 30 Oct 2012 12:18

All - EU tyre labelling confusion - GeoffC

It's a little confusing - I think it's best to take the labeling as a gudeline only - not as a presision measurment of performance. I have been scouring the pages of the internet comparing and generally being boring! My conclusion is that it gives Jo & Joanne Public a guide only - a bit like buying washing machines and fridges with labels on - only a guide - doesn't really give the full story of how they will perform on YOUR CAR with YOU driviing....

There are also overlaps: Looking at other review sites, from real world input, I would say that a good 'C' wet grip rating (for example) might be as good as, or better than, a poor 'B' rated one. Also - whatever happend to the letter 'D'??? Not seen any 'D' ratings for anything!

Yes sizing makes a difference as well as loading so IMO there are too many variable to be able to give an exact rating on any one tyre - just a rough guide. I would still check out what real world people have said on Tyre test sites.

Edited by GeoffC on 30/10/2012 at 12:20

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Tue 30 Oct 2012 12:59

All - EU tyre labelling confusion - Chris M

This looks like another scheme where manufacturers will tune their products to do well in the test at the expense of real world performance, just like fuel economy and NCAP.

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Wed 31 Oct 2012 11:28

All - EU tyre labelling confusion - Engineer Andy

Not sure why the "D" ratings are unused - I did remember reading something that had to do with vans, but can't remember where. A general explanation can be found here (no endorsement of the website/service generally - just the result of a web search):-

www.tyre-shopper.co.uk/eu-tyre-labelling.asp

Seems the "F" ratings are not used on the wet grip ratings as well, according to them.

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