Does anyone know if these new tyres make any noticeable difference to fuel consumption or are they just a gimmick?
I check my tyre regularly and they are usually pretty close to the recommended pressures.
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I found that the Conti Ecos were good, but I tried Michelen Ecos and they did not suit the car at all, the handling was ruined! I think the ecos do make a difference, but I suspect driving style, correct pressures, etc, will make more!
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Well all I can say is that they lasted close to 40k miles on my car, so whether they made a difference on my fuel or not, I don't know - but having just replaced them, I hope they did save me some pennies as I needed that to pay for the rubber!
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I have also been wondering about the claims made about these tyres. I am sure they do make a difference to fuel consumption, however Michelins are not cheap. Compared to say a budget tyre (many of which also have hard compounds) I wonder if the extra cost really can be off set against the saving on fuel over the life of the tyre.
It is something that really is difficult for the average motorist to monitor (without a test track and laboratory conditions) you are at the mercy of the manufacturers claims.
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I use Continental and am delighted with the results.
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Poor braking in the wet, but otherwise alright. A bit noisy when down to 3.5mm.
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My opinion is thus:
Surely the only way for them to work is to reduce friction?
If there's one place I certainly do not want there to be less friction - it's the tyres of my car.
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Rolling resistance. And it certainly shows in the wet...
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>>Surely the only way for them to work is to reduce friction?
Yes, but there's a distinction that's important.
I fully agree that the friction between tyre and road should not be compromised.
The rubber's internal friction, however, is something that could be safely minimized. This internal friction represents a mechanical loss, or hysteresis, and converts a proportion of the energy that goes into continuously deforming the sidewall and tread into heat, that represents a loss.
The problem is that the hysteresis can contribute to the tyre/road friction, and so, minimising internal friction usually does have a slight effect on tyre/road friction.
Nothing to do with rubber is ever simple or logical - a truly fiendish engineering material IMO!
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I knew it must be more complicated than my layman's version. Obviously I didn't realise just how much more!
I would always be worried though of the compromise. I will continue to buy my tyres based on grip levels.
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I will continue to buy my tyres based on grip levels.
And so will i, who am old enough to remember just how terrible michelin x and zx tyres were in the wet.
Anyway we've had the three days of summer, looks like wet grip is the number one priority again.
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2008 ADAC tyre test for 195/65 R 15 V tyres are on the web here: tinyurl.com/3skgto
You need to know that "Kraftstoffverbrauch" means "fuel consumption" and that a low score is best. Michelin Energy Saver is indeed the best of the bunch. It is also the hardest wearing.
These tests are conducted under careful conditions.
If I am not very much mistaken, the tyre test results in Which? magazine are the same as the ADAC ones - the same raw data is used, but they give different weightings to different tyres.
Edited by tyro on 27/05/2008 at 10:45
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In the end there will always be a compromise. Hard compond = long life and good rolling resistance, soft tyre does, but gives very good grip.
F1 has been doing these equations for 50 years.
I suppose the question for me is, 'is the reduced grip still comfortably inside that which I am likely to need in daily motoring?'
The problem is that when that kiddy runs out into the road (an event that happens every 25 years!) the soft tyres are what you need. However there is another alternative; drive within the cars capability. After all, who last did 0 - 60 in anythink like 3 times the car's spec, leave alone Clarksons burning tyre displays.
You pays your money and ...
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Happened to work the costs through the other day when looking for a new pair of tyres.
Fuel saving for my 12k a year was about £40 compared to average tyres but the outlay for a set (can only properly compare a full set) was £520 compared to £300 for the ones I bought (a wet weather balanced tyre).
Even with a claimed extra 40% life from the Michelins they still worked out more expensive per mile.
The figures look even worse for the Michelin if you sell the car before getting their full life, damage one, get an irrepairable puncture or suffer premature wear due to alignment issues.
Anyway for me wet grip is crucial and I'm happy to pay for that in other areas.
David
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Michelin claim that this tyre can save up to 200ml of fuel over every 100km travelled. What a sweeping generalisation this is. Also note those two magic words "up to"
When you take into account all the other everyday variables that are not mentioned; Engine size, driving style, differing road types, laden vehicles etc etc etc. The actual amount saved can be much reduced.
Personally I dont think they are worth the initial outlay. If you really want an energy saving tyre, then go for some Eco Contact 3's. They will be at least as good in the real world and more sensibly priced.
Edited by craneboy on 27/05/2008 at 21:42
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craneboy makes a very good point about comparing mpg.
It makes me laugh when I read on here how people are not achieving the stated mpg - especially when comparing a hybrid to a diesel for instance.
There are too many variables that affect mpg from one day to the next, did you accelerate exactly the same as the day before, is the ambient temp the same, was the overnight temp the same etc etc.
But on the subject of these tyres, then I have tried them and rate them highly, I cannot say I have noticed a difference in mpg for all the reasons I have stated but they are quieter and last allot longer than most other brands.
I put allot of faith in the consumers association tests and the Michelins just nudge the Continentals in terms of overall score (both are best buys though).
Interestingly enough the vredestein sportrac3 was the best overall, the only downside being that many people stock it.
(Mods - please tell me if I am breaking any rules using test data from a different site).
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Michelin claim up to 5% improvement in fuel economy compared to the non energy Michelin.
Cheaper brand tyres could well have a fuel penalty over the standard Michelin tyre let alone the energy equivelent.
The "Up to" comes about because the tyre will only save fuel if its rotating, if you're stuck in a traffic jam it will save you zero.
The demonstration I've seen saw a 406 and I think a Xantia? held on a ramp and then released, the distance the car covered was measured, the car then had the energy tyres fitted and returned to the same position on the ramp and released. The distance the car rolled with the engergy tyres fitted was considerably further, not far off twice the distance if my memory serves me correctly.
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1% per corner, reputedly. I can't see why this should not be true, probably a feature of carcass design and rolling resistance. This sort of feature would be an improvement on merely making sure your tyres are pumped up properly.
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My fuel economy was reduced by 5-10% when I changed from OEM fit Dunlop SP Sport 2000E tyres to Goodyear Eagle F1 GS-D3's on my car, which gives credence to the concept that tyre choice affects fuel economy.
However, the better the fuel economy and wear rate a tyre gives, the less grip it will give. Frankly I'm not cheap enough to dice with safety in the name of saving a few pence, so it was the best performing wet tyre on the market that was the only tyre good enough for me.
The 'low resistence' Dunlops were terrible - every roundabout in the wet was accompanied by flashing DSC lights. Since the Eagle's went on the light comes on only when provoked..
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According to the American DOT test results printed last week in Autobild showed that a 25% reduction in rolling resistance of tyres equalled an increase of 1% in economy so to gain an increase of 10% you probably have rewritten the laws of physics.
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However the better the fuel economy and wear rate a tyre gives the less grip it will give.
This may be broadly speaking true, but it is not always true in individual cases. There are some tyres (mostly pretty cheap ones) that are neither good for fuel economy / wear rate nor for grip - and are beaten on all fronts by other tyres.
Equally, there are some tyres that are hard wearing but don't give great fuel economy and vice versa.
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However the better the fuel economy and wear rate a tyre gives the less grip it will give. Frankly I'm not cheap enough to dice with safety in the name of saving a few pence so it was the best performing wet tyre on the market that was the only tyre good enough for me.
I'm not convinced about this argument either - the Conti Ecos were very good grip-wise in the wet, but the Michelens weren't - its what suits the car.
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If a tyre has a low rolling resistance that doesn't necessarily mean it has poor grip. The compound used, design of the carcass and tread all make a difference.
Edited by nick on 29/05/2008 at 09:56
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The Michelin carcases were the same, its the added ingredient to the rubber in the tread that makes the difference.
Michelin found that using the ingredient in some of the 4X4 tyres improved grip and changed over to it without rebadging them energy.
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