Drivers using new tyre labels to choose the most efficient wheels could still be spending too much money, a new report suggests.
Emissions Analytics has found that tyres deemed to be less efficient under the new labelling system may actually produce the same performance as higher rated equivalents.
The most efficient tyres - that help a car produce the lowest carbon dioxide emissions as it drives along - are given an A-rating.
But according to Emissions Analytics' Nick Molden, tests indicate some F-rated tyres perform just as well as those rated B at medium speeds.
Tyres have carried labels with fuel efficiency ratings since 2012 but Mr Molden says there isn't enough data on them.
Emissions Analytics' research involved speeds of between 40 and 70mph and found little difference between the two tyre ratings up to 55mph.
Mr Molden says the results suggest people buying B-rated tyres will not save very much fuel if they drive mostly in urban areas, where speeds tend to be lower.
However, those who do plenty of motorway driving are likely to see more of a difference.
Copyright Press Association 2014