Sub 750kg trailer tyre pressures

[WESTY66]

Hi, done a bit of googling on the above and found a myriad of different answers so I thought I’d ask on here for personal experience. I have a trailer which I’m carting my Harley about, the total weight is around 600kgs Tops, fully loaded. It has 155 70 R12C tyres on, 104/102N.
Can anyone with relative experience give me a heads up on the pressures I should be using? They’re currently at 45psi but I haven’t been anywhere with it yet and setting off to Austria on Friday.

 

[Howard H]

Any use Ady ?although Ivor Williams should know they seem quite high !

 

[David and Sally]

I too have a small trailer and a bike trailer.

TBH I pump them up till they 'look' right but not too hard that they bounce when towed.

Highly unscientific. I'm not sure it really matters with a trailer tyre unless under a lot of weight or high speed.

Probably circa 35 psi I guess.

 

[Waveski]

I’ve been towing dinghy trailers for years and use tyre pressure of about 30 psi. The tyres and wheels are the same size and specification as the original mini car. The weight of boat and trailer would probably be about 400 kgs max. I also have a large box trailer for rubbish runs to the tip etc Wheels are the same as the dinghy trailer but loading could be much as 750kgs so I use a tyre pressure of 35kgs. Never has any problems and tyres seem to wear ok.
I’ve never seen any real definitive pressure specifications and I go on the old mini pressures.

 

[WESTY66]

Yes

Any use Ady ?although Ivor Williams should know they seem quite high !View attachment 327360

I seen that table Howard, I thought they were a bit high!!

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[tacr2man]

pressure listed here , also other sizes .
The tyres are more than capable of carrying the load , so maximum inflation /load pressure isn't needed .
In a constant ambient , In this case inflate to 50psi , then drive approx 20 miles and recheck pressure , you are looking for a 4 psi rise . If it is more then they need to be increased by 1 psi for every 1psi increase over the 4psi .
If there is less than 4 psi rise then when cold deflate by 1 psi for every 1psi less than 4psi from original pressure .
You will need to redo for new weights carried .

 

[Ridgeway]

i run mine at 3.40 Bar (50 psi) , pretty sure they are the same size as the OP mentions

 

[pappajohn]

Yes

I seen that table Howard, I thought they were a bit high!!

Also meaningless.
175-60/14 could be on a 3500kg plant trailer at 95psi or a 1000kg box trailer at 35psi.

Also, 20.5 x10 is listed twice, one at 36psi...one at 70psi.
Obviously for two completely different trailers.

 

[WESTY66]

Also meaningless.
175-60/14 could be on a 3500kg plant trailer at 95psi or a 1000kg box trailer at 35psi.

Also, 20.5 x10 is listed twice, one at 36psi...one at 70psi.
Obviously for two completely different trailers.

Yep PJ it’s a minefield, I’m going to have a go at tacr2man methodology?
Also I’ve pumped em up to 60 psi as it’s easier to let them down than pump em up. Also I read somewhere that if pressures are too low the tyres could overheat???‍

 

[PeteH]

Ive had a Little trailer with a 400kg limit, for some years now (in excess of 5). I keep them at 30psi regardless of load. So far they appear to have suffered no harm. Biggest issue (in my case) is the time it spends static, I keep checking for tyre wall cracking so far so good .

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[Emmit]

Hi,
For what it's worth I include a site that used by tuggers (which I suppose is what you are in these circs)

Because you've got tyres, well over the necessity, the site recommends, wait for it, 23psi.

Tyre Pressure Calculator | Meet the Trudgians

the-trudgians.com

 

[tuscancouple]

Can anyone with relative experience give me a heads up on the pressures I should be using?

Tyre pressures for our trailer, which is plated at 1300 kgs and carries two Harleys, is 60psi. This was recommendation of trailer manufacturer and has never caused a problem in years of towing

Mick

 

[TheTwoOfUs]

One of the dangers of having the pressure too low is that the tyre becomes the suspension, there being more give in them than in the Indespension units which can cause the trailer to wallow. I know this from when I towed a trailer behind the Wing when anything untowards is obvious - believe me.

 

[TheBig1]

a ball park figure of 40psi works for most small trailers

 

[dpsuk999]

On my smart trailer with a smart car I have mine set at 65psi for the past 4 years and never had a problem

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[tonyidle]

A pressure up to the limit for the tyre will never cause a problem on a trailer. The correct pressure will however let the tyre do its job as part of the suspension.

 

[tacr2man]

Tyre pressures should be quoted with tyre spec as tyre pressure limits for tyres vary considerably dependent as much on their construction as by load .

 

[Vipar]

As an ex class 1 (HGV) driver London to Athens we used to run at 95 psi then check tyre temperatures by touch if they were warm then we added 5 lbs checked again after another 20 miles once they were cold to the touch we knew that the pressure was right for wear and tear and maximum grip in the wet worked for me for 20years lorry tyres a expensive done the same on my MH

 

[WESTY66]

Update. I put 60 psi in and did 190 mls to harwich, tyres felt ok, got off the ferry at the hook of holland and drove to Taufkirchen (south of Munich) 550 miles or so and 31 degrees most of the way, checked in at the aire, took off the trailer, parked the Moho up and went back to check the pressures 20 mins or so since they stopped rolling, tyres Luke warm and still 60psi in!! It towed very well?

 

[Vipar]

Can’t beat a good feel much better than a mechanical device ????

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