Temporary Spare Tyre - Pressure

Poulgorm

What pressure should you put into a temporary spare tyre?

Checked mine today - for the first time in 3 years - unused, so far. It was at 22 psi. Inflated to 40 - it might be a long time before I check it again.

What pressure should I have put into it and what pressure should it be at, if I actually have to use it? Normal pressure - around 32psi ?

samih

I'd inflate to the max the tyre wall permits. Guessing it will be something like 50 psi. That way it will most likely be usable when you need it. The more air it has the longer the thread will last too should you ever need to use it.

djimi

Is it a space saver or a normal sized tire? 40psi sounds very high for a space saver.

MrDerp

Why not put a compact compressor in your boot? That way you might even avoid a change altogether.

Renegade Mechanic

Space savers typically have a far higher operating pressure than normal tyres. Most of the ones I see have a max of around 60 psi so 50 would be well safe, 55 ideal. Check the markings though. Also, the whole Max pressure thing is purely the max safe pressure. The tyre is absolutely guaranteed against failures at that pressure and under that load but much over and the guarantee is gone. Most normal car tyres are rated to 50psi now as opposed to 44. But either would be uncomfortable and potentially unsafe on the road.

A space saver is unsafe by its very nature, just look at the width of the thing. Hence the warnings about low speed and distance. Pressure will make no difference to the severely reduced handling and increased braking distance. Having a lower pressure will simply destroy the tiny sidewall as it needs it to support the weight so keep it at max or close (within 5psi).

Normal car spare wheel should be kept only a few psi over whatever pressure you keep your wheels at and checked every two months.

Poulgorm

Renegade Mechanic wrote: »

Space savers typically have a far higher operating pressure than normal tyres. Most of the ones I see have a max of around 60 psi so 50 would be well safe, 55 ideal. Check the markings though. Also, the whole Max pressure thing is purely the max safe pressure. The tyre is absolutely guaranteed against failures at that pressure and under that load but much over and the guarantee is gone. Most normal car tyres are rated to 50psi now as opposed to 44. But either would be uncomfortable and potentially unsafe on the road.

A space saver is unsafe by its very nature, just look at the width of the thing. Hence the warnings about low speed and distance. Pressure will make no difference to the severely reduced handling and increased braking distance. Having a lower pressure will simply destroy the tiny sidewall as it needs it to support the weight so keep it at max or close (within 5psi).

Normal car spare wheel should be kept only a few psi over whatever pressure you keep your wheels at and checked every two months.

Thanks Renegade, you seem to know what you are talking about. "Max 60 psi" is stamped on the space saver, so I will put it at 55 psi.