Tyre pressure
Submitted by randall df223 on Tue, 2014-04-01 21:17
Here's a question thats as long as a piece of string....
Max pressure on the boat trailer tyres is 65 psi. When we drive to monkey mia soon we will load the boat up reasonably, but not over the trailer weighting. I have set the tyre pressure to 55 psi. Is this enough? Should I go to 65 psi or should I check the pressure one hour into the journey?
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hilly9
Posts: 282
Date Joined: 13/10/12
i'd just always set them
i'd just always set them about 5 psi higher than your vehicle
randall df223
Posts: 6454
Date Joined: 08/08/11
My vehicle recommendations
My vehicle recommendations are really soft... 29 psi front, 32 psi rear when loaded.... I just think that is so not enough.
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Vinesh87
Posts: 2751
Date Joined: 02/04/11
The 65psi is only for the
The 65psi is only for the max load. How heavy is the atm and close are you to that?
randall df223
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Date Joined: 08/08/11
The trailer springs are
The trailer springs are rated to 1200kg and I reckon fully loaded we would be close to 1000kg.
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Vinesh87
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Date Joined: 02/04/11
Whats the max loading for
Whats the max loading for the tyres. should be written next to the 65psi
randall df223
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Date Joined: 08/08/11
Says max load single 670 kgs
Says max load single 670 kgs (its a single axle trailer)
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randall df223
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Trailwr springs are 600 each
Trailwr springs are 600 each side
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Vinesh87
Posts: 2751
Date Joined: 02/04/11
Ok so your running about 80%
Ok so your running about 80% of your max load.
I would be running them at about 60psi. Normally the tire will say e.g 65psi max load at cold inflation so even though roads are hot you should be able to go to 65psi cold.
From memory a good rule of thumb is:
Pump the tyres up to 60, load the boat up and go for a decent drive for the tyres to heat up. Re check the tyre pressure and if it has gone up by more than 4psi you need to increase the pressure a bit. If they have gone up by less thean 4 psi you could drop a little.
But i'm no wheel guy haha
P.s I run my Trophy tyres at 50psi which is the Max! But i am on the limit!
Starbug
Posts: 563
Date Joined: 27/08/09
Sounds close to the mark. My
Sounds close to the mark.
My trailer is rated to 2000k. Twin axel running 8ply LT tyres that have a 680kg rating at 65psi cold.
Trailer plate recommends running 410kpa cold pressure (59.5psi)
So I guess you should run 60psi if you are at 1000kg.
kempy
Posts: 810
Date Joined: 28/05/09
Pump ours up to 60psi if not
Pump ours up to 60psi if not the tyres try to rip off the rims when turning tight corners.
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Rig
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Date Joined: 27/12/06
65
Sounds like a similar setup to me, I run mine at 65psi which are the tyres max. No probs yet
randall df223
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65 when cold??
65 when cold??
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Rig
Posts: 2925
Date Joined: 27/12/06
Thinks so
Yeah I think so. The spec on my tyre side wall says 65 cold. I have done a few trips like that up to kalbarri no problems. The tyres are 6 months old think they are black lion brand LT.
my boat weighs a bit and on a single axle anything less than 50 and they bag out a bit
sea-kem
Posts: 14984
Date Joined: 30/11/09
I go 55 psi Randall as they
I go 55 psi Randall as they will expand with heat when driving. But as said depending on the load you are taking, you need to consider they aren't overinflated to cause uneven wear.
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randall df223
Posts: 6454
Date Joined: 08/08/11
Thanks everyone. I reckon I
Thanks everyone. I reckon I am in the ball park between 55 and 65 psi. Years ago I read an article about tyres and the way I understand it is if theyre not inflated enough you get too much bulging and too much heat in the side walls. Thats when you get blow outs (we had two last year! Could have been old tyres as well). But ive never been sure as to how much is too much pressure to start with.
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tim-o
Posts: 4657
Date Joined: 24/05/11
Yep underinflation is baaaad.
Yep underinflation is baaaad. But you dont want them overinflated too. If theyre LT tyres, 60 is fine. On a vehicle, pressures a set relative to weight to achieve a balance between correct tyre contact, and comfort. Harder settings will give a harsher ride but lower settings although more comfortable, if too low will wear out tyres more and generate more drag thus more heat. The boat doesnt care about the ride. Go with 60 and check pressures at stops, they WILL get higher after driving especially on hot roads during the day. And another point, even if the tread is still good, quite often on trailers the tyres perish before wearing out, so check for cracks in the tyre which indicate they are old, and replace them if so
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randall df223
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Date Joined: 08/08/11
Cheers Tim. These are 12
Cheers Tim. These are 12 months old. I replaced them last year when we had the blow outs. The previous ones were on the trailer when I bought the boat. God knows how old they were.
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Starbug
Posts: 563
Date Joined: 27/08/09
OK as you have LT rated tyres
OK as you have LT rated tyres your inflation pressures will be high. They are designed to run at higher pressures, and will only achieve their load rating at these pressures.
If you are saying the load rating is around 650kg then I would be running them at the max pressure or close to it for the load you are carrying.
Tyres degrade after 5 to 7 years. Rubber goes brittle and micro cracks appear in the sidewalls leading to blowouts. Regardless of wear you should be looking at replacing them after this period of time.
tim-o
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Sun (uv) perishes the rubber
Sun (uv) perishes the rubber so keep them out of the sun when possible
I am, as I've said, merely competent. But in an age of incompetence, that makes me extraordinary.
Starbug
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Date Joined: 27/08/09
That and ozone. Granted ones
That and ozone. Granted ones exposed to UV will deteriorate quicker, but even tyres that are garaged will fail.
cell
Posts: 215
Date Joined: 06/07/13
+1 Tim-o when driving up
+1 Tim-o when driving up north down South allow for rd heat I would be settin between 5-10psi lower then rating a blow out on a boat trailer at speed could result in a costly trip, hope your trip goes well can't wait to see some pics, it's epic country up that way
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Ian S
Posts: 71
Date Joined: 20/01/14
Cold inflation pressure
Is the important figure, don't worry about what they are when hot, the manufacturers take all of that into account when setting inflation pressures.
As you are running near the maximum load go for 65psi.
rocklobster
Posts: 363
Date Joined: 27/12/09
As an indication, over a
As an indication, over a period of time overinflation causes the tyre to wear in the centre of the tread and underinflation causes the tyre to wear on the outer sides of the tread ( underinflation also causes excessive heat build up due to the sidewall flexing constantly with the rotation of the tyre = blowout ) . 60psi will be a good starting point
randall df223
Posts: 6454
Date Joined: 08/08/11
Here's the report on tyre
Here's the report on tyre pressure. Started yesterday with 60psi. Checked them one hour in and they were well and truly off my tyre guage (which has a max of 60psi). The needle went hard around. Let the tyres cool at northampton and increased the pressure to 65 psi cold. Checked this morning after about two hours at a roadhouse and the pressure was 69 psi both tyres. So from now on, towing the boat fully loaded, the tyres will start at 65psi. :)
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tim-o
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????? So you had well over 60
????? So you had well over 60 when hot and now you are increasing the cold start pressure??? If 60 gives you ideal tyre footprint I would maintain that pressure so you would need to set at maybe 50 cold
I am, as I've said, merely competent. But in an age of incompetence, that makes me extraordinary.
tim-o
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Date Joined: 24/05/11
Edit, I just read what Vin
Edit, I just read what Vin said above, so you have followed that I guess which kinda makes sense, because if the pressure is too low, you will create more heat in the tyre and will increase the pressure by more
I am, as I've said, merely competent. But in an age of incompetence, that makes me extraordinary.
Vinesh87
Posts: 2751
Date Joined: 02/04/11
Haha I know when you read it
Haha I know when you read it sounds stupid but yes not enough pressure bulges and heats up the sidewalls.
Well thats what I have been told anyway, seems to work!