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4 Jul 2012, 14:30 (Ref:3101927) | #1 | ||
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Tyre Pressures in Trailer Tyres.
I've always run my trailer tyres at around 35-40psi pressure. I recently got a couple of tyres for someone and the sidewall figures said 90psi, these were 12 inch 8 plys. I've just bought myself a pair of 6 ply 13 inch and the figures read at 65psi, the tyres I've taken off say run at 45psi.
So should I be running the pressure at the amount it states on the sidewall or a bit lower as I am not loading them to the maximum amount? The sidewall states maximum weight of about 680kg Twin axle trailer probably grossing about 1800 kg maximum, except when I load it with hay and then it may go to over 2 tons. |
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4 Jul 2012, 15:04 (Ref:3101944) | #2 | ||
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The pressure marked on the sidewall is the maximum pressure to which the tyre should be inflated. Optimum pressure for a given application will vary & will always be lower than the permissible maximum.
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4 Jul 2012, 15:42 (Ref:3101973) | #3 | ||
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Tim take this advise from someone who mulled no less than 3 tyres in one trip a few months ago and fortunately I have a 6 wheel trailer or lord alone knows how I would have got home. I made the same assumption looked at the sidewalls 90psi, got a heavy car so thought way to go 80psi in each. On the way homeI lost two tyres where the rubber valve had literally blown out under the pressure as I am sure they increased as it was a hot day and did the third one in pulling out of a garage after having to stop every few miles to top up pressures. Its only then I realised the original tyres fitted by Brian James had metal bolt in valves so the moral is you must use these if you are going to run high pressures. I have now dropped down to 45psi with rubber valve stems and have had no further problems and they dont look under inflated at all.
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4 Jul 2012, 16:28 (Ref:3102005) | #4 | ||
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Size, type and load on the tyre govern optimin pressure.
I have a plate on my trailer (BJT) which tells me what to run at for a selection of tyres. Which is usefull. 35 psi is what I use. |
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5 Jul 2012, 17:04 (Ref:3102495) | #5 | ||
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We had a spate of tyre problems with a Motor Shuttle until we upped the pressure to about 80psi.
If the manufacturer of your trailer still exists, talk to them. |
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5 Jul 2012, 18:36 (Ref:3102526) | #6 | ||
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I use 8ply caravan tyres on my race box inflated to 45psi never had a problem, running road tyres at 80psi is asking for trouble if it is "handling" wrong then it is loaded wrong !
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5 Jul 2012, 21:24 (Ref:3102583) | #7 | ||
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There is a formula for working out tyre pressures, on the side of your tyres there will be a " maximum load single " at a maximum psi .
Lets say for example , it states 1460kg at 65psi on your tyre , and your trailer or caravan weighs 1075kg . What you do is 65 divided by 1460 = 0.0445 Then , times 0.0445 by 1075 = 48psi . |
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Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa ! |
6 Jul 2012, 08:15 (Ref:3102747) | #8 | ||
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Gordon, the weights stamped on the tyres are per tyre not gross weight, in my tyres case It's 640kg per tyre and 65psi
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6 Jul 2012, 11:07 (Ref:3102801) | #9 | ||
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I dont like 38psi in my road car as its too hard, imagine what 90psi would do in a trailer
You would have to imagine the trailer would bounce a bit (lot), having very little give in the sidewalls at that pressure to absorb even the slightest bump... |
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6 Jul 2012, 11:12 (Ref:3102803) | #10 | ||
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Use the right tyres for the job, and run the pressures recommended by the tyre or trailer firm.
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6 Jul 2012, 11:33 (Ref:3102814) | #11 | ||
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BJ recommend 36.2psi for my original tyres on my trailer which the sidewalls state 45 at full load. My new tyres have a stated pressure of 65 psi at full load and while I wouldn't run that high I think 36 will be too low.
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6 Jul 2012, 11:41 (Ref:3102816) | #12 | ||
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a simple rule of thumb is the trailer tyres needs to be inflated for the weight of itself and the car its carrying. On my 4 wheel trailer with a fiesta on board, i would put pressures equivilent of say a road going focus (35ish psi) - certainly not 80-90 psi which is dangerously overinflated.
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6 Jul 2012, 16:03 (Ref:3102920) | #13 | ||
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I dont think its dangerously over inflated if you have tyres built for the job and bolt in valves. The 10inch tyres on my 6 wheeler have 95psi stamped on the side as max so I am sure they must be safe at that with the obligatory bolt in valves (see my previous post), don't forget the BJ 6 wheelers is designed to take a fully loaded LWB sprinter in fact I have a customer who has a recovery firm and he has had to turn jobs down with his fleet where this trailer would have coped. Again though for carrying my 1400kgs Camaro I won't use them at anything like that pressure.
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6 Jul 2012, 16:26 (Ref:3102925) | #14 | |||
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Quote:
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10 Jul 2012, 13:26 (Ref:3104639) | #15 | ||
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For many years I've run a 4 wheel trailer on 145/80 X 12 tyres and always run at 45 lbs pressure.
I always now carry 2 spares as many years ago I was taking a friends race car to him in Harrogate and I must have run over something on the kerbside as both nearside tyres disintigrated at the same time. |
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13 Jul 2012, 10:01 (Ref:3105963) | #16 | ||
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One question being missed here, are you running commercial tyres or road tyres ? 8 ply are commercial trailer tyres so would expect to run them at higher pressures than the equivilant 6 ply road tyres.
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