Surely you could save the same amount through a myriad of other factors?
Yeah but you could do those AS WELL as getting Energy tyres.
I gained about 2mpg in the Prius, 3-4mpg in the Passat, which are doing 52-63mpg and 50-54mpg respectively (although this was not tested scientifically, the difference was obvious).
The biggest difference with them though and possibly of greater benefit to the environment is that they last for absolutely ages – possibly twice as much as normal tyres – despite only costing a bit more. 25k on the Michelins on the Prius and they only seem half gone. Got Nokians on the Passat and they are excellently quiet.
They are not simply harder compounds, they contain scilica which is well known as a tyre additive that improves wear and decreases rolling resistance. It’s the same for bike tyres.
Oh and beware reading google articles. Early versions of Michelin scilica tyres (E3A I think) weren’t so good in the wet – but newer ones are better. I’ve certainly never had a problem.
http://www.tyres-online.co.uk/technology/silica.asp
I recommend Nokian V – brilliant.