Trailer wheels tyres

Tyres too hard will shake the boat to bits, too soft and they will get hot and possibly blow out or roll off the rim.

Start at about 40psi for a mid weight boat, if the tyres get warm add 5psi and try again. If nothing warms up let 5psi out and see if it's warming up, if so put the 5 back in. If still cold let another 5 out etc. Also note the heat of the hub, if that gets warm it needs a service. 

The 60psi on the side wall is the max for the tyre at max load, 300kg per axcel for 8 inch I think, most boats all loaded up on the trailer will be 200kg ish so the max should not be needed. 

Ian 99, I'd say you haven't experienced a blowout from an over pressurised tyre - 60 and 90 psi have been mentioned here!

I've seen (and helped clear up) the aftermath of a trailer tyre blowout at high speed on a French autroute and it is messy. With heavier trailers it can even overturn the towing vehicle, that gets really messy!

I'm sure that somewhere here on the 'net there'll be a page with advice on tyre pressures for lightweight trailers but I can't actually be bothered to look at present. I'll stick with what I've done for 30 or so years and keep my tyres in good condition and pressures around 30psi. In possibly hundreds of thousands of miles I've had 1 blowout and maybe half a dozen flats (oh yes, and a lost wheel!!)

Ever heard of it happening? http://www.trojantrailers.co.uk/store.php?faq=4 doesn't appear to suggest it is a risk.

I thought everyone who towed dinghies regularly used low tyre pressures. AFAIK it is standard advice and I'm pretty astonished with some of the suggestions on this thread.

At 25psi with those small tyres, I'd have thought there's a fairly high risk you'll hit a bump and stretch the bead away from the rim enough to lose all the air in the tyre.

I'm sure that somewhere there must be a list of tyre pressures for axle loads for tyres, but I think 6 ply tyres go up to 75psi at maximum axle load of about 500kg.

Remember as well that those small wheels are only rated up to 60mph - anything above this they start to get seriously warm! Not that anyone ever exceeds the speed limit with a trailer of course

If you can, fit ten inch wheels with radial tyres - these allow a maximum speed of 150kph

Having experienced a "blowout" on a boat trailer on the motorway a few months back (not my trailer) I can say with reasonable authority that it is a complete non event in comparison to one on a car due to the trailer being so light. My passenger (the owner of the boat and trailer!) didn't even realise there was anything major wrong - he thought the banging was the trailer strap come loose. On getting out though, having coasted down from about 50 to 0mph, there wasn't much left of the mudguard, interesting skid marks on the side of the boat, and no sign of any tyre left (spread over about 1/4 of a mile of M4), just a completely destroyed wheel rim.

I'd be a lot more worried about killing your hull. Trailing is bad for hulls but softer tyres are better because the boat is bounced around less. I really wouldn't pump dinghy trailer tyres to the max. 25psi should be plenty. Keelboat trailer tyres are different and need high pressure, due to the weight of the boat.

Regarding changing tyres, I think it is pretty difficult to DIY without the tools that tyre shops use to peel the tyre on and off the wheel. A good type shop will change a trailer tyre for you - I've had to get it done due to a puncture.