Trailer Tyre Pressures

[davidpbo]

Tyres 185 x R13s

4 wheel trailer.
Rubber suspension

Trailer weight 450Kgs
Boat cc 1900Kgs

What tyre pressures?

I used 55psi this time with boat on trailer.

I drop the pressure to 30 psi towing the empty trailer any distance to stop it bouncing too much.

I am wondering whether I could reduce both tyre pressures further maybe 45 and 25 ps to limit bounce.

 

[Tim D]

The correct tyre pressures depends on the combined weight of trailer and its boat and the size and make of tyres. You will need the following information to calculate correct PSI for any given combination:

(Gross) weight

Load rating of tyres at max PSI (the sidewall will have this information - something like 600kg at 44 PSI etc)


xxx kg (tyre load rating) x 2 = aaaa kg (combined max load of the tyres)

aaaa (combined max load) ÷ gross trailer weight = bbb

max tyre PSI ÷ bbb = ccc (inflate tyres to ccc psi)

You do the maths

 

[davidpbo]

I will have to have another look the sidewalls as I couldn't see that data.

 

[Lakesailor]

It is very tiny in a box adjacent to the bead.

I find that I get the best towing results by lowering the pressure until the sidewalls start to bulge a bit (very technical)
For instance on the Dockrell on 10" wheels (two wheels) the gross weight is 560Kgs.
The tyre are rated to 316Kgs each (so they are taking 280 kgs each) and whilst the maximum pressure of the tyre is something like 44 psi I find it rides best at about 35 psi.