Tyre pressure measurement 22 September 2022 at 8:48PM edited 22 September 2022 at 8:53PM in Motoring 55 replies 1.7K views

jimmo

Iceweasel said:

Are we now metric - we've been metric since 1972. No school in UK has taught in Imperial since then.

Let me think about that over the next pint.

RobM99

Beer in pints, football pitches are in imperial, horses in hands, fathoms still in use? Feet for altitude. 

400ixl

Jenni_D said:

And to circle back to (part of) the original question ... tyre pressures should be as per the tyre manufacturer recommendations, not necessarily what's printed in a handbook or on a wheel arch.  

Tyre pressures on vehicles should be as per the vehicle manufacturers recommendations, but should not be outside of the tyre manufacturers recommended range. Tyre pressure depends on the weight distribution of the vehicle and load it will be carrying. The tyre manufacturer just sets the safe range for its product.

sevenhills

400ixl said:

Tyre pressures on vehicles should be as per the vehicle manufacturers recommendations, but should not be outside of the tyre manufacturers recommended range. Tyre pressure depends on the weight distribution of the vehicle and load it will be carrying. The tyre manufacturer just sets the safe range for its product.

VW recommend 61 PSI, but the local authority that I work for think they know better and write 65 PSI on the wheelarch.

Mr.Generous

jimmo said:

Iceweasel said:

Are we now metric - we've been metric since 1972. No school in UK has taught in Imperial since then.

Let me think about that over the next pint.

Loads of imperial stuff knocking about - even when my time is up and I'm 6' under (rather than 1.83mtrs) there's no getting away from it. What size screen has your TV got? What size fence panels are in your garden? The tyres on your car show the rim size ... in inches, mens jeans are 34" waist - ever seen them shown in mm? - and before someone else says it - yes manhood !!

Ectophile

The tyres on your car show the rim size ... in inches

But the first figure on most tyres is the width in millimetres.

The three numbers are the width in millimetres, then the ratio of the sidewall height to width (as a percentage), followed by the rim size in inches.

They do that because rims have been made in inch sizes for so long that it would be a major hassle to go metric.  The manufacturers would have to come up with a completely new set of tyre sizes.

facade

RobM99 said:

Beer in pints, football pitches are in imperial, horses in hands, fathoms still in use? Feet for altitude. 

A cricket pitch is one chain, horse races are in furlongs (10 chains), ship speed in knots....

UK spanner sets are DIN, Japanese cars are ISO, so you can't undo half the bolts because the DIN spanners don't have 15,16.18 or 21mm...

jimmo

facade said:

RobM99 said:

Beer in pints, football pitches are in imperial, horses in hands, fathoms still in use? Feet for altitude. 

UK spanner sets are DIN, 

What's DIN? My spanners and sockets are AF

sevenhills

Ectophile said:

They do that because rims have been made in inch sizes for so long that it would be a major hassle to go metric.  The manufacturers would have to come up with a completely new set of tyre sizes.

I believe cycle tyres all used to be 20" and 26" but we now have metric, 70cm

facade

jimmo said:

facade said:

RobM99 said:

Beer in pints, football pitches are in imperial, horses in hands, fathoms still in use? Feet for altitude. 

UK spanner sets are DIN, 

What's DIN? My spanners and sockets are AF

DIN = Deutsches Institut fur Normung (German Institute for Standardisation) ISO = International Standardization Organization. (Yes they use Z's in the spelling)

They set the nut size (AF and height) that should be used with different thread sizes.

An M10 thread has a nut that is 16mm AF ISO or 17mm AF DIN.  If you have a partial spanner set to DIN sizes, there is no 16mm AF spanner.