Trailer tyre pressures

[Joe_Cole]

I have a four wheel trailer carrying my boat, which weighs about 2 tonnes. The tyres are marked "6.00/6.90-9 Max 85psi. Max load 625kgs"
Different people have recomended that I use tyre pressurs between 40 p.s.i and 110 p.s.i.! Obviously the maximum I should use is 85 p.s..i, but can anybody tell me what the best pressure to use is?

Regards

Joe Cole

 

[snowleopard]

asked the manufactures of my trailer (1 ton boat, 4 wheels). they implied that the pressure wasn't critical but went for a high figure (40psi in my case). as long as there is only a small amount of deflection of the side wall where the wheel is in contact with the road you shouldn't have any trouble. you're interested in low wear, cool running, not great cornering. truck tyres are always pumped up till they're almost rigid.

here's a formula to tell if you're in the right parish:

work out, for your car first (tyre pressure x tread width x no of wheels)/vehicle weight

then do the same for the trailer. it should be similar or a little higher.

 

[Dean]

Hi, had my four tyres changed yesterday, they carry about 2 1/2 tonnes.
I was told run them at 60 PSI.

 

[Guest]

Your tyres seem typical 9 ply trailer/van tyres. I agree with other respondent that 60/65psi should be about right , and recommendation is always hard inflate to reduce sidewall flexing and consequent heating. However if in doubt ask the experts. I have found
Indespension Ltd
238, Waterloo St
Bolton Lancashire
BL1 8HU

Tel: 01204 397999 to be very helpful.

 

[Avocet]

Whatever you do, don't exceed the maximum pressure on the sidewall! Also, if you run them too low, the trailer will be harder to pull and the tow car will use more fuel. On the other hand, if the trailer suspension is too hard, lowering the tyre pressures will improve the ride and give the boat an easier time of it. If you get the pressures too low, the tyres will overheat and (at worst) blow out. trial and error is the best thing. Start close to the recommended maximum and if it all works, leave it at that. If the trailer bounces about too much, lower the pressures a bit and stop after (say) 5 miles on the motorway and feel the tyres to see if they're significantly hotter than the ones on the car. If not, and the trailer is still bouncing, lower the pressures a bit more until you get the best compromise.

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