Tyre Fuel Efficiency Ratings - any real world experience Options

[TonyS]

Hi,
I'm looking for tyres for our Freelander 2 and notice that most have the Fuel Efficiency rating of either C or E, with some more expensive options being B. According to something I saw the difference between A and G is 7.5%, it's not clear whether that's 92.5% vs 100%, or 100% vs 107.5%. Either way if it's a linear scale then the difference between C and E would be 2.5%. What I was wondering was whether people have seen real world differences either for better or worse between different rated tyres?

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[Redivi]

According to National Tyres, the difference between grades is 3 or 4%
'D' isn't used

https://www.national.co.uk/information/comp...-tyre-labelling

Reduced rolling resistance is often at the expense of increased wet braking distance and doesn't feature in my tyre decisions

[The Rookie]

The test relates to tyre rolling resistance ONLY.

At circa 60mph aero drag is much much higher than tyre rolling resistance, even a 10% improvement in the tyre is likely to see just a 1% improvement in fuel economy (and well within test to test variation so you'd need to drive hundreds of miles to be able to actually confirm it.

You gain more by making sure the tyres are always properly inflated, by leaving unnecessary clutter at home and a LOT more by driving style.

Like for like by all means pick the one with lower rolling resistance but I wouldn't sacrifice other attributes for it.

This post has been edited by The Rookie: Wed, 24 Apr 2019 - 12:20

[DancingDad]

Given the choice between wet grip and fuel rating, I'll have grip every time.

[TonyS]

The test relates to tyre rolling resistance ONLY.

At circa 60mph aero drag is much much higher than tyre rolling resistance, even a 10% improvement in the tyre is likely to see just a 1% improvement in fuel economy (and well within test to test variation so you'd need to drive hundreds of miles to be able to actually confirm it.

Thanks, that is a very good point and logically I don't see how tyre measurements can possibly account for anything else.

I suppose some of the informal comments are based on the same misunderstanding that I had, for example from National Tyres "The difference between each category means a reduction or increase in fuel consumption of 3-4%." Even though at the top of the same page they say tyres only account for 20% of the power used.

[notmeatloaf]

The explanation from Goodyear seems more thought out.

The difference between an A rating and a G rating could mean a reduction in fuel consumption of up to 7.5%. To put this in real terms, choosing A-rated tyres instead of G-rated tyres could save you more than 6 litres of fuel every 1,000 kilometres.*

At an average petrol price of £1.10 per litre, that adds up to cost savings of more than £220 over the life of the tyres.*

Don’t forget, you’ll also be reducing your environmental impact!

*Based on an average consumption of 8 litres/100km, a fuel price of £1.10/litre, and an average tyre mileage of 35,000 km. Actual fuel and cost savings may vary depending, among other things, on tyre pressure, vehicle weight and driving style.

What the wet grip ratings mean
In an emergency situation, a few metres can make all the difference. For a passenger car applying full brakes from 50mph, a set of A-rated tyres will brake up to 18 metres shorter than a set of F-rated tyres. *

Note: You should always respect the recommended stopping distances when driving.

Seems to me a very sensible thing to rate, seeing as before all people had to go on were the brand. Plus, like electrical appliances, it pushes manufacturers to improve their tyre design - clearly having an "F" wet braking test will mean the only people to buy it are those foolish enough to want some ditch finders.

[The Rookie]

I suppose some of the informal comments are based on the same misunderstanding that I had, for example from National Tyres "The difference between each category means a reduction or increase in fuel consumption of 3-4%." Even though at the top of the same page they say tyres only account for 20% of the power used.

Black circles is even worse!

Putting the scores into perspective, if fitting the worst scoring tyres in this category, you could end up using 6 litres more fuel every 625 miles than if you fitted 'A' rated tyres - so, potentially, 'A' rated tyres could save you enough in fuel bills to buy a new set of tyres!

It's bad enough using an obtuse 6l/625 miles (which is of course 1000km, but why not use 9.6litre per 1000 miles) but its also very dependant on what the current economy of the car is making it meaningless.

To try and make sense of that my current vehicle does 36.7mpg (WLTP, actual is 35mpg but I'll use 36.7) which is 7.7l/100km, or 77litres/1000km. So that 6l claimed saving is nearly 10%, so sounds like BC are talking BS and using rolling resistance as total resistance saved!

[Redivi]

I discovered the difference between A and B rating wet grip the day I drove my wife's budget shod Fiesta

Driving at what I regarded as perfectly normal speed on my tyres, the front end went wide on two wet roundabouts in a row

She's now got a Picanto that came with 155/70/13 Chinese ditch-finders
It understeers in the dry and is very twitchy to keep in a straight line

The trouble is that there aren't many good tyres in that size and they have so much tread that I won't have an excuse to change them for some time

[The Rookie]

I won't have an excuse to change them for some time

This would be a good one.......

It understeers in the dry and is very twitchy to keep in a straight line

Much better than Chinese tat and not that expensive
https://www.blackcircles.com/catalogue/hank...kUaAsOlEALw_wcB
or
https://www.blackcircles.com/catalogue/avon...f?tyre=22505380

[samthecat]

I won't have an excuse to change them for some time

This would be a good one.......

It understeers in the dry and is very twitchy to keep in a straight line

Much better than Chinese tat and not that expensive
https://www.blackcircles.com/catalogue/hank...kUaAsOlEALw_wcB
or
https://www.blackcircles.com/catalogue/avon...f?tyre=22505380

Wife had the Avon ZT5s on her Hyundai, they were fine. That originally came on some hard compound crap that could only be described as dangerous in the wet.

[Redivi]

Thanks

I think what I'll do is follow recommendations for the Toyota Aygo that's very similar and has a lot of suspension components in common

[notmeatloaf]

Not that one tyre proves the whole system works but I put Firestone Roadhawk tyres on recently - EU A for grip - and they are absolutely fantastic. Quick road with sharp bends near me and no understeer at all even if you really throw it around.

Definitely wouldn't have got that on a £50 tyre a decade ago. I used to use ZT5s but they are rubbish in comparison.

[TonyS]

Not that one tyre proves the whole system works but I put Firestone Roadhawk tyres on recently - EU A for grip - and they are absolutely fantastic. Quick road with sharp bends near me and no understeer at all even if you really throw it around.

For a moment I thought you meant you'd fitted just one tyre. In my case I actually have, the car had one tyre completely worn and unsafe/illegal, so we replaced that with whatever was cheapest. With this combination, new tyre on one side, worn on the other, the car pulls quite markedly towards the side with the worn tyre. Whether that's do do with different diameters or rolling resistance I don't know. Either way it's annoying so I hope moving the odd tyre to the back might reduce the effect.

[Redivi]

Better check the front suspension, ball joints and tracking if one tyre is wearing as badly as you say

[cp8759]

All the tyre data you want: http://www.tyrereviews.co.uk/Tyre-Tests/#summer

[nigelbb]

I have always gone for the tyres that are highest rated in wet weather. For my Range Rover I have the choice of A to E. At 50mph the difference in braking distances between each grade is roughly 3m. Making the difference between A and E 12m. I don't know how realistic these braking distances are in real life but it seems crazy that it should be legal to sell tyres that perform so much worse than the best. It's not even necessarily the most expensive ones that ar graded A.

[The Rookie]

Well Blackcircles have now changed their claims following an explanation of the laws of physics.
https://www.blackcircles.com/general/tyre-l...ling/tyre-label

The EU's somewhat more scientific approach is explained here.
https://ec.europa.eu/energy/sites/ener/file...20-%20tyres.pdf

This post has been edited by The Rookie: Fri, 3 May 2019 - 09:40