fuel economy

Does tyre pressure affect fuel consumption

In a number of our blog articles here at Sell My Car Essex we’ve discussed getting good fuel efficiency from your car. As part of that, we’ve discussed tyre pressures. But do they really make a difference and, if so, how much?

Does tyre pressure affect fuel consumption

The short answer to the first part of the question, yes tyre pressure does affect fuel consumption, an under-inflated tyre it increases the car’s drag increasing fuel consumption. One study – by the National Highway Traffic Safety Administration in the USA – concluded that a 1% drop in tyre pressure (compared to what it should be) resulted in a 0.3% reduction in fuel economy. A not always noticeable 10% under-inflation increases fuel consumption by 2% and a hopefully fairly obvious 20% under-inflation does it by 4%.

As well as under-inflated tyres being a huge safety problem, making sure they’re inflated correctly could mean as much as a £4 saving in terms of the average UK tankful of petrol (June 2022 figures) over driving on 20% under-inflated tyres.

Bear in mind that tyres might naturally lose one or two PSI each month, and that temperatures can make a difference, so it’s worth checking tyre pressures regularly.

As well as the safety and fuel economy points made already, there are other reasons to have good, correctly inflated tyres in place:

  • You reduce the risk of uneven tread wear, so your tyres could last longer
  • You minimise the rolling resistance, so your engine doesn’t have to work unnecessarily harder
  • Braking is, in many cases, more efficient

Make it a regular routine to check your tyre pressures and inflate where you can. If budget allows, invest in an air pump with an accurate meter to let you do it at home, so you don’t have to go to the nearest petrol station with a working air facility. Many of these can plug into the car’s electrical outlet so they can be kept in the car for tyre emergencies, although there is a limit to what they can do in puncture situations or at other times when there is a rapid loss of pressure. Some high-end portable air pumps include a facility to fill a punctured tyre full of foam so you can get it to the nearest garage for a replacement tyre (or, depending on the foam type used, a repair).

Tyres, of course, are just one factor affecting performance.  If your tyres are top notch and the pressures are perfect but you’re still experiencing poor fuel economy, there could be one or more factors at play and it might – just might – be time to sell your car and use the cash towards a newer model. Enter your reg number at Sell My Car Essex and let’s see if we can give you a great valuation.