Horse Box Quiry

Does anyone have any idea of the correct tyre pressures for a horse box? we have a double hunter trailer, just had it serviced and we were told that the tyres should be at 40psi or higher, seemed high so after a second opinion.
Cosidering we are looking at two ton towing, that that was his suggested off load pressure.....
Thanks, Peter.

I know it doesnt help much as I cant remember the formula, but more info would be needed, weight of loaded trailer, tyre load ratings, max pressures, axle loadings.

http://www.tyresafe.org/data/files/caravan 08.pdf This may help you work it out.

Our caravan is only 1200kg, but the handbook recommended tyre pressures are 47 psi ... and you can really tell iwhen they get below 42ish ..

single or double axle? what make of trailer? is there not a plate on the inside of the jockey door with the recommended psi stamped on? 40psi is not that high, some of the ifor trailers recommend 50-55 psi!!