In New Zealand, just two Mirage models are offered: LS (base) and GLS, both with the CVT automatic transmission only.
They both have identical drivetrain/technical specifications, yet the LS has a better fuel economy rating than the GLS, burning 6.1% less fuel. Why? Mitsu points to the wheel/tire spec on the two cars as the culprit.
N.Z. AA explains:
(Off-topic... I think it's funny that they call the 165 width tire "skinny", but not the tire that's only 1cm wider. Duh.)the difference is a result of the variance in wheel sizes. Skinny 14-inch steel wheels are fitted to the LS models while the GLS versions are fitted with 15-inch alloy-wheel rims with slightly wider tyres.
http://mirageforum.com/forum/showthr...e-Association)
Mirage LS
1.2 L
CVT automaticMirage GLS
1.2 L
CVT automaticCombined fuel economy: 4.6 L/100 km
21.7 km/L
51.1 mpg (US)4.9 L/100 km
20.4 km/L
48 mpg (US)Wheel & tire 14" Steel w/ Wheel Cover
165/65R1415" Alloy
175/55R15
How do different wheel /tire size and style cause the GLS to get worse fuel consumption?
- the slightly narrower tire will have a slightly better drag coefficient and smaller frontal area
- that flat plastic 14 inch wheel cover is probably more aerodynamic than the open spoke alloy wheel
- the different tires probably have different rolling resistance coefficients
- the bigger alloy wheels & lower profile tires may have more of their mass concentrated further away from the rotation axis, which would need more power to accelerate
I haven't compared the overall diameter of the 2 tires, but I assume they're very close. If they're not, though, gearing could also be slightly affected.
UPDATE (Jul 11/2013):
Mitsubishi again points at wheel/tire choice and its effect on fuel consumption, this time regarding the new Mirage Sedan G4 / Attrage:
22 KM/LITER. (with 14 inch wheels) Having the lightest body weight, it isn’t surprising that the Mirage G4 has the lowest fuel consumption in its class. [...] Equipped with 15-inch wheels, the Mirage G4’s fuel efficiency is rated at 21 kpl.
source: http://business.inquirer.net/131241/...ry-chapter-two
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FYI: here's a dramatic example of how these wheel size/style issues can affect fuel economy: