Relying on the sticker inside the door may not be ideal. It must assume a particular vehicle loading that might not b right and it assumes the tyres are the ones supplied with the new vehicle. That may not be correct either.
The correct tyre pressure depends on the load that the tyre is carrying and the specific tyres being used. None of us here know that important information.
Start by getting the vehicle weighed when in maximum "touring" loads (full of fuel and water and ready to go).
Then get the load/pressure tables from the manufacturer of the tyres you are actually using. All tyre manufacturers have them, but sometimes they are hard to get.
It is worth the effort to get the pressure correct. Pressures either too high or too low will increase wear rates and reduce performance.
My own experience and what I have been learning of late, one plan of attack is pumping your tyres to what you may thing is good when they are cold say 65 psi. go for a drive about hour and test your pressure again now if they have increased by more then 4 psi you will need to add more air, now if they are with in the 4 psi you can then deflate the tyres.
It can be pain staking but the rewards are there with ride comforts, cornering and stopping along fuel econ, tyre wear savings.
I only this week from my motor racing engineer friend tells me if you place a straight edge under neath the front and back of your tyre now measure the foot pint and all your tyre around the vechile should be the some. As yet myself have not gone down this path trying to make my new tug handle the job of towing my caravan better.
I am using the 4 psi method and so far so good I believe I am almost there 36 in the front, 42 in the the rear of the crew cab ute towing my single axle 2 tonne caravan with 198 KGS on the ball. I am running 42 psi on the caravan. Now after 3000 kilometre trip I do believe I have it near right. The car feels great, my back is not suffering all good.
Just remember to start off with cold temperatures and retest at hot. I been checking mine at lunch time after a 1 to 2 hour drive.
I do hope this is of some help as I have spoken with tyre salesmen and none have agreed with the other. So it's a fun learning curve. Ralph.
Hi. We have had 1 since new and the maximum pressure on the pirellies that came on it new say 70 psi maximum cold pressure. I find 65 to be a nice ride and handling.
Err 10lb higher rather than 10lb lower.. As said above.. Check tyre temps ( with hand on tread) when stopping every now and then.. If they feel hot.. Check pressures.. Chances are they will be low pressure for the weight..
This has been a question on my mind for a while now. We have a Jayco Starcraft 20 footer with dual axels the compliance plate is in kpa and I can't find a conversion.
I'm running 44psi atm. Maybe a bit soft?
Safe travels
-- Edited by Phil C on Saturday 25th of October 2014 12:48:31 PM
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P B Crockart EX RAAF Electrician,
Aircraft Avionics tech. Senior high school teacher.
Relying on the sticker inside the door may not be ideal. It must assume a particular vehicle loading that might not b right and it assumes the tyres are the ones supplied with the new vehicle. That may not be correct either.
The correct tyre pressure depends on the load that the tyre is carrying and the specific tyres being used. None of us here know that important information. Start by getting the vehicle weighed when in maximum "touring" loads (full of fuel and water and ready to go). Then get the load/pressure tables from the manufacturer of the tyres you are actually using. All tyre manufacturers have them, but sometimes they are hard to get.
It is worth the effort to get the pressure correct. Pressures either too high or too low will increase wear rates and reduce performance.
Cheers, Peter
Best advice on this thread from Peter.
Using the cold to hot pressure difference method "the old method" relies on the volume of air in the tyre and the temp rise to provide an answer. If you UNDER inflate the temp will get hotter quicker BUT you risk destroying your tyre.
The "old" method was 3psi rise in pressure for a 13' or 14" wheel when I learned engineering and cannot IMHO be equated to modern tyres.
As Kiwi says higher pressure better than low.
-- Edited by Baz421 on Saturday 25th of October 2014 09:30:27 PM
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Why is it so? Professor Julius Sumner Miller, a profound influence on my life, who explained science to us on TV in the 60's.