French magazine calculates the real savings using low-rolling resistance tires
Every time an automaker announces a green signature label, one of the factory-installed features to reduce fuel consumption is probably low-rolling resistance tires. French magazine Autoplus did a test drive on a regular car, to see how much fuel these tires save. The magazine wanted to run the test because France is considering adopting a bonus/malus system on these tires for 2010, whereby tires that save fuel would get a tax exemption.
For the challenge, Autoplus got two Peugeot 308s, one fueled by gasoline and the other fueled by diesel, and they kept on changing their tires. They tested fuel consumption with regular tires and with "CO2 reducing tires." Their verdict? Keep security in mind. Only low-rolling resistance tires that came from well-known brands (Michelin, Goodyear, Continental and Pirelli) performed correctly and kept braking distances and other security features almost intact. Their winner was Michelin (which are made in France) which stayed safe while offering fuel savings of 1 percent with gasoline and 3.8 with diesel fuel. Of course, it doesn't matter if your tires are lrr type or not - keep them properly inflated.
[Source: Autoplus]
Reader Comments (Page 1 of 1)
T2 7:45PM (6/20/2008)
Does Autoplus know how to scientifically test ? Why on earth introduce the diesel variable ?
I would think you should have more onus on comparing the driving style of all the participants first. Then use two identical cars to get a better sample size. Finally put LRR tires on each car and retest.
The best test put on by Driving Television had cars follow each other on a planned route with drivers swapping vehicles every half hour.
These figures are meaningless. LRR tires are the oxygenated copper speaker wires of the industry. Even Toyota gave up on them with the introduction of the 2004 Prius.
T2
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T2 7:48PM (6/20/2008)
Rubbish !!!!!
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rj 8:35PM (6/20/2008)
If lrr tires are a safety hazard, I don't see why they are even allowed.
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Andy 9:43PM (6/20/2008)
Could someone explain to me how a Diesel engine can tell whether it is being loaded by tire resistance versus something like, say, gravity? All the engine sees is the crankshaft.
This sounds like pretend science to me.
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Chris M 11:14PM (6/20/2008)
Um, Toyota is still using LRR tires, though they did switch to one with a much longer tread life.
Yes, LRR tires will reduce fuel consumption by reducing rolling resistance, but keeping the tires fully inflated has a much more substantial effect.
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why not the LS2LS7? 12:40AM (6/21/2008)
Tires know which kind of fuel your car runs on and perform differently accordingly?
That makes no sense. Sounds like this test is bunkum.
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mike baz 5:59AM (6/21/2008)
I bought such tires from Toyo, bad decision, everything is worse except I do get better mileage on the highway. Won't repeat my mistake.
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Philip 6:54AM (6/21/2008)
The extra weight of the diesel engine on the front tyres may have caused the additional gain in efficiency over the petrol engine?
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BrianM 10:40AM (6/21/2008)
FWIW, I found similar results myself. Happened to have Kumho Touring A/S tires (can't find the treadwear rating currently, but they were ranked in the top 5 LRR when I bought them) for 80k miles, and then swapped to Nokian WR with substantially lower treadwear ratings. I've only got about 12k on the tires (7~8 months), but have found a decrease in fuel economy of about 8% or so. That means going from 49mpg average to about 45mpg average.
My tires are properly inflated, checked every 400 mils or so (weekly, and whenever I fill up), car is in good running condition and I'm the main driver ~ so driving habits are the same.
I did *NOT* find any reason, other than winter performance (I live in Wyoming), to change. The tires handled beautifully, left me with no complaints on practiced panic stops and I never found the ABS to come on in those practice braking sessions. If I lived somewhere that I didn't spend 5 months driving in the snow (or wanted to deal with the hassle of changing wheels/tires), I'd still be running the Kumhos in the summer.
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Wildgoosechase73 1:08PM (6/21/2008)
I'm sorry but I have a problem with low traction tires......
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MikeW 3:26PM (6/21/2008)
People aren't going to have to shop for low rolling resistance tires, low rolling resistance features will make it into all tires.
We are to the point where general all season tires can generate 1g peak deceleration on braking, and better ($) all seasons can generate 1g average braking.
Basically all the customers expectations are met, so next was treadlife (see Michelin HydroEdge 800 UTQG), and now it is on to rolling resistance.
France doesn't need a mandate for improved tires, as the US didn't need a mandate to phase out filament bulbs.
LED based lighting will replace CFLs by 2010. (now what to do with all that mercury?)
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Bill 4:18PM (6/21/2008)
Trivial amount of mercury in a CFL compared to the mercury in the fly ash of the extra coal burned by sticking with an incandescent instead of relamping to the CFL.
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Dave 10:16PM (6/21/2008)
What we need is an easy way to compare the rolling resistance between tires. Just like how tires are rated now for treadwear, top speed, load carrying, wet weather braking, etc, they need to be rated for rolling resistance.
Then let the consumer make the decision on what tire best fits their needs (or desires).
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