So-called "range anxiety" might not be the only issue for New Zealand's growing ranks of electric vehicle owners - it seems many might be getting around on tyres that need a pump-up.

Of more than 500 owners just surveyed, nearly two thirds said they only check their tyre pressure every six months or so - and some others never bothered at all.

The findings come from Flip the Fleet, an ongoing citizen science project that regularly polls hundreds of EV owners around the country.

Earlier surveys have revealed how most EV owners wouldn't go back to petrol, and suggested how some blokes won't buy one because it might dent their macho image.


When asked in the latest survey about what sort of tyres they used or preferred, many couldn't say and others answered "round ones", "black ones" and "ones without a puncture".

Some said "pure laziness" prevented them from checking their tyres often enough, but smarter owners realised the importance of the tyres for vehicle efficiency and targeted low rolling resistance brands.

"Having properly inflated tyres is not just a legal requirement, it greatly increases energy efficiency and range of the EV and it keeps the drivers safer on the road," said Alan Wilden, an EV owner from Dunedin and spokesman for Flip the Fleet.

"Having the right pressure and making sure the tyres are well aligned greatly increases the life of the tyres too and means you save even more money from an EV."

Low pressure increased emergency braking distances, especially in wet conditions, but over-inflating tyres could be a problem too.

This increased the chances of getting a puncture and could change steering and lateral grip, making the car harder to control when evasive manoeuvres or emergency stops were required.

Best practice guidelines for all vehicle owners was to check the tyre pressure at least once a month as tyres naturally lost pressure since they were last pumped up.

Wilden predicted that petrol and diesel car owners would be less diligent.


"Our survey showed many owners have increased their tyre checks since getting an EV, so petrol and diesel car owners must be running on even flatter tyres."

New Zealand aims to have 64,000 EVs on our roads by 2021, including one third of government vehicles, through incentives such as allowing them to use special vehicle lanes, exempting them from road user charges and subsidising projects through the Low Emission Vehicles Contestable Fund.

As of June, 8696 EVs were registered in New Zealand - most of them in Auckland - marking a sharp increase from just 205 in the same month five years ago.