While checking the tyre pressures today which weren't too bad considering the number of potholes we have in the UK, I decided to check the tyre pressure of the full size spare as well which is fitted with a 205/55 R16 Muchelin energy.

Measured Tyre Pressure 45psi (3.1 Bar)

Maximum tyre pressure moulded into tyre wall 50psi (3.4 Bar)

Handbook temprary spare wheel R18 61psi (4.2 Bar (p237 of handbook)) which is way above the maximum rated pressure.

Pressure for a 205/55 16 tyre from fuel filler cap 33 psi (2.3 Bar)

95% of the time the car only has me, hence the lower tyre pressures taken from the filler cap.

So which of the above is the correct pressure for the spare?

I go for a bit more than the rest because I dont check it so often, but should it not be the same as the road wheels? unless its one of those POS super skinny ones

Well you order a full size spare but in reality it is a steel wheel the same size as the alloys fitted to the S and Greenline models, so I thoughgt it could be at 2.3Bar which is the standard pressure for those. The slightly higher pressure to compensate for the fact the other wheels are 225/40 R18 7.5J compared to the sprae 205/55 16 7J so it is a bit slimmer by 1/2 inch. Hence the lower speed rating as the corner with the spare will handle a bit differently.