Question of the week: Is there an ideal tyre pressure to avoid potholes?

David Ross, Editor
Fri, 09 May 2025

Dear Honest John,

"I drive a Suzuki Vitara with Continental tyres set at the higher Eco pressure for economy. This gives great miles per gallon on motorways, but on potholed roads around town the ride can be bumpy. I can reduce the tyre pressure to the lower Comfort setting, but would softer tyres be more likely to suffer damage from potholes? Alternatively, is there another make of tyre that would give both good economy and a softer ride?"

- RG

Dear RG,

Tyre pressures are always something of a compromise. Lower pressures allow more deflection of the tyre which is good for ride comfort, whereas higher tyre pressures are better for economy as they reduced rolling resistance. As there is no pressure level that will account for all circumstances it is a matter of deciding which characteristics are most important to you and how you drive.

High tyre pressures reduce the likelihood of a puncture occurring from the tyre being pinched but also carry a potential higher risk of being punctured by a sharp edge or debris than a lower pressure, so there is no perfect pressure but a compromise between the two extremes is likely to give the best puncture resistance.

You can use a retail website such as blackcircles.com to view a wide range of tyres in the required size which also shows the economy rating, but ride quality is typically determined by the aspect ratio or sidewall size of a tyre in relation to its overall size and tyre pressures.

You may also wish to consider fitting smaller wheels, as these would typically have a taller sidewall for better ride quality and less width, which usually results in lower rolling resistance and therefore better fuel economy.

You could also consider fitting XL-rated tyres which are designed to carry heavier loads and have tougher sidewalls.

Ask HJ

Did hitting a pothole break my car?

In October I hit a pothole at speed. Immediately afterwards warning lights came on and the car started juddering and wouldn’t accelerate properly. Luckily there was a refuge close by and I pulled over. When we came to a halt there was a lot of smoke coming out of the exhausts and a strong smell of fuel in the cabin. I called the roadside assistance and the car was recovered and spent five weeks at the closet dealership while it was tested and repaired. A fuel sensor and spark plugs were replaced and the final diagnosis was that I had put bad fuel in the car as apparently the fuel had separated when the technicians drained the tank. I’m really flummoxed as to how I could have driven 100 miles at speed on bad fuel only for this to manifest the instant that I hit the pothole. It would be great if someone could explain this to me please as the dealership can’t.

It does seem unlikely that putting bad fuel in your car would have caused this issue to occur at the exact moment you struck a pothole, but there are a few factors to consider. Firstly we would be asking what exactly the technicians meant by 'bad fuel' - if this was the case we would want to try and trace where the fuel was purchased and investigate further. It is also worth bearing in mind that fuel added to the tank would not immediately enter the engine unless the tank was almost empty, so even if the fuel was bad you would have been able to drive normally for some time. If you are unsatisfied with the technician's explanation you may wish to consider having the car inspected by an independent engineer.

Answered by David Ross

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