Tyre Pressure
Submitted: Sunday, Feb 20, 2011 at 16:16
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sun chaser
G'day i just heard about putting 42psi in my caravan tyres when i get up north on the hot roads to protect the walls of my tyres. Does anyone do this and is it true?
Peace
Reply By: Member - Joe n Mel n kids (FNQ - Sunday, Feb 20, 2011 at 17:42
Sunday, Feb 20, 2011 at 17:42
short answer is no...... but !!!
You need to know the weight of the van, the type of tyres, remember heat will increase the pressure also so at 42psi cold it could possibly get to 50psi hot and some tyres will be so hot you can not touch them with bare hands .....
Higher pressures will be better for fuel economy, will add stability to it with less rolling and will run cooler with loads, only "protection" to side walls will be they wont flex as much...
Lower pressures will soften the ride and tend to adsorb corrigations better .... but will run hotter as the tyre is flexing more
Another thing to think about is a balloon, pump it up hard and the slightest touch with something sharp it will burst, half blow it up and it is harder to pop, the same goes for tyres, very hard tyres will blow out with only a small sharp object, let them down and it can flex in the tread and sides before it will penetrate..
Cheers
Joe
AnswerID:
446062
Follow Up By: CSeaJay - Sunday, Feb 20, 2011 at 20:42
Sunday, Feb 20, 2011 at 20:42
Joe
Your whole answer is informative but I respectfully disagree with your direct answer an first para.
Running tires high on high speed btumen is best and 42 is not too hgh.
FollowupID:
718391
Reply By: Fred G NSW - Sunday, Feb 20, 2011 at 18:08
Sunday, Feb 20, 2011 at 18:08
Sun chaser, you need to read what the ratings on the tyre fitted to your caravan are, and don't exceed them.
The Barum's I run are rated to 65 psi and 950kg load rating each.
I run them now at 45psi after experimenting with pressures, and find that pressure works great for those tyres on that caravan. I don't run 45psi for the road heat, but more for the weight and ride and economy, and the tyres don't overheat. You may need to experiment a bit as
well to get it right. I'm no tyre expert, but that works for me.
I sure hope they are still available when it comes time to replace.
Cheers from Fred
AnswerID:
446068
Reply By: snapper49 - Sunday, Feb 20, 2011 at 19:26
Sunday, Feb 20, 2011 at 19:26
If your tyres are getting that hot they are under inflated
High pressures will not heat a tyre up
Most caravan tyres are light truck and readily accept pressures around 45-65 lb
I rum my coromal corvair single axle at 50lb
Never had any problems and definately havent had hot tyres
AnswerID:
446074
Follow Up By: Member - Graham H (QLD) - Sunday, Feb 20, 2011 at 20:56
Sunday, Feb 20, 2011 at 20:56
All tyres warm up with travel How do you know how hot they are
I have tyre monitors so I know exactly whats going on.
4lb from cold to hot is the norm and friction between the tyre and the road warms them up..
I have found that the sunny side ones usually run 3deg hotter than the cold side.
If they were under inflated they would rise to a higher pressure so obviously they are not.
Cheers.
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718392
Follow Up By: snapper49 - Monday, Feb 21, 2011 at 01:04
Monday, Feb 21, 2011 at 01:04
Im taking about this quote
" 42psi cold it could possibly get to 50psi hot and some tyres will be so hot you can not touch them with bare hands"
If tyres are getting that hot there is something wrong and its usually under inflation for the load they are carrying
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Follow Up By: Member - Graham H (QLD) - Monday, Feb 21, 2011 at 09:30
Monday, Feb 21, 2011 at 09:30
Ok I agree that post was most uninformed an 8lb rise definitely signifies the tyres were too low for a start
But they do heat up if underinflated.
Another thing that makes them hot on a car is those full width stone guards.
I had one when we started out and one not very warm day the rears on the car were up to 65deg. fronts were only at 40.
Took the stoneguard off and they went straight back to 45deg.
Never ever used it again. It did have a bit cutout of the middle but still impeded the airflow under the car.
FollowupID:
718443
Reply By: CSeaJay - Sunday, Feb 20, 2011 at 20:53
Sunday, Feb 20, 2011 at 20:53
Short answer is yes it is ok. Assuming sealed hot roads
On high speed gravel I'd definatly drop them
On low speed off road I'd drop thm more
I have a rule of thumb a served me
well. Van tires as high as highest car tire (usually rear tire)
On low seed/sand the van is as low as the lowest car tire - usually front
CJ
AnswerID:
446087