Tire pressure question

[Mike82ndABN]

Just to play it safe, I thought I would ask the experts here what I can safely run in my tires. They are radial according to the tire.

 

[Retiredwarhorses]

It's printed on the tire...and in the -10

 

[Mike82ndABN]

Yea I saw the tire and I've read the dash ten and dash twenty. Just trying to get real world opinions from you guys, who I value greatly. I have this fear of a split rim shooting through my head as I air up.

 

[jadatis]

I am able to calculate it for you but need more information about tires and car and use of it.
Will give text I used in other topics and saved , so I wont have to write it all over again , but might have some off the subject text for here.

Tirepressure advice is all about load on tire and speed ( and sometimes about alighnment - camber angle).

So if you can give details of car and tires , I can calculate an advice pressure with some reserve for things like, pressure-loss in time, unequall loading R/L, incidental extra load, misreadings of pressure scales,and misyudging of weight, etc.

This is from tires next and can be read from sidewall:
Maximum load or loadindex.
Kind of tire to determine the AT-pressure/pressure needed for the maximum load up to maximum speed of tire, or if lower 160km/99m/h/reference-pressure, wich is not the maximum pressure of tire.
Maximum speed of tire, most given as letter ( Q=160km/99m/h,N=140km/86m/h fi)
If you have offroad or tires looking like that , with large profile blocs that cover a part of sidewall, also mention, they are allowed lesser deflection then a normal road tire, and wich the tire maker used to determine the maximum load (to my conclusion the case for the Bridgestone tires on Ford Explorer in the Ford/Firestone affaire) Looking at your picture , it shows large profile blocks , but they dont seem to cover part of sidewall so probably they dont have to be lowered in maximum load for the reason I gave above.
If you cant find all of it give sises of tire and Loadkind, then I will google for it.

From car next and mostly can be found on same plate as the original pressure advices:
GAWR and GVWR ( Gross Axle/Vehicle Weight Rating)
But best would be to determine the real weights in your use on seperate tires or estimate it as acurate as possible, by weighing per wheel(pair) or axle.
Maximum speed , you dont go over for even a minute in your use, eventually different for different situations, for instance when towing or fully loaded.This apart from trafic regulations, if you drive faster then allowed give that speed. Nature punnisches with tire-failure, police only with a penalty.
Give all that and I will calculate and give a picture of one of my filled in spreadsheets in my answer.
If other then original tires, indead as is already answered other advice is needed, a stiffer tire ( fi C-load instead of P-tire) needs a higher pressure for the same load, or the other way around, has lower loadcapacity for the same pressure.

Greatings from a Dutch pigheaded self-declared tire-pressure-specialist.

 

[Mike82ndABN]

I'm honored you waited since March 2014 to make your first in this thread.

 

[jadatis]

I'm honored you waited since March 2014 to make your first in this thread.

Can be that I registered then to react on a topic , most likely about tire-pressure or tires, and it took a while before aproving, and I forgot to answer to the topic then.

But in addition : The sise of your tire gives me the idea that you have pretty oversised tires for the vehicle ( but can be wrong).
this can mean that only one tire can bare the complete Gross axle weight rating ( wich is the highest weight you are allowed on the axle by law).
ten a pretty low advice pressure can be the outcome.
Mayby even as low as 20 psi .
For on track ( Wich I think your vehicle also comes often , yudging the sand on rimm) 80% of pressure for on road is allowed and for on Sand even 50% , wich means in sand mayby even as low as 10 psi !!!!!!!!!!!!!!.

But lets calculate to see if I am right.

 

[Mike82ndABN]

I've been meaning to find out, if an airplane attempted to take off on a treadmill, would it be able to do so? Let's say the airplane needs to reach 100 mph to take off and the treadmill belt is coming at the planes tires at 100mph.

 

[jadatis]

I've been meaning to find out, if an airplane attempted to take off on a treadmill, would it be able to do so? Let's say the airplane needs to reach 100 mph to take off and the treadmill belt is coming at the planes tires at 100mph.

Huhh???

Must be I am from Holland ( Europe) that I cant make the sense of this post.
What is a Treadmill.

 

[Mike82ndABN]

It's a thing you run on at the gym. Moving belt under your feet. If you run 10 mph and the belts spins at 10 mph, you stay stationary. What about an airplane?

 

[DatGuyC]

It's a thing you run on at the gym. Moving belt under your feet. If you run 10 mph and the belts spins at 10 mph, you stay stationary. What about an airplane?

Not sure if this is a joke question, but an airplane doesn't rely on its tires to push it along....

So a treadmill would have no effect on the movement of the airplane, otherwise how would they fly in the air?

 

[Mike82ndABN]

Right, but would the resistance from the treadmill cause drag?

 

[DatGuyC]

The airplanes tires would spin twice as fast, but that's about all that would happen.

 

[jadatis]

OK then to the air the plane is standing still and it needs airspeed to lift off.
I have more unorthodox ideas and one of them is the about desighning an Airport at sea.
For that I came by a book in the library from a Dutch specialist Henk Tennekes.
Its the reason why planes best take of and land against the wind.
Example when wind is 100 m/h and plane is able to lifty off at 100m/h , then it needs zero runway when taking off against the wind.
When wanting to take of with this wind in back , it needs even 200m/h groundspeed to get 100m/h airspeed.
The same for landing, but will never reach the landing stripp .

But wind and direction is a serious factor used by airplaines and airports.

 

[Mike82ndABN]

Jdatis, and if the plane increased speed to 120 and the treadmill matched it to 120 in the opposite direction, and then 150 for the plane and 150 for the treadmill, is there a point where friction melts bearings? Or tires explode? If the plane keeps increasing speed and the treadmill matches the speed, can it ever lift off?

 

[jadatis]

I thought this topic was about tire-pressure!

But the speed of plane is made by the turbines and so when airspeed is made by that 100 m/h and treatmill speed is 100m/h then tires rotate as if speed 200m/h , and will sertainly blow by the heatproduction. this needs higher tire pressure to give lesser deflection so bending of rubber of tire, so lesser heatproduction.
But everything has its end, you cant go highening up the pressure endlessly.
But now I realise that if realy this , then plane almost lifts of so weight on wheels practically zero so no deflection so no heatproduction.
This only for the tires , not for the wheelbaring

 

[Mike82ndABN]

Thanks. I've always wondered about the physics on it

 

[tigertank]

so tire pressure u guys use is?

 

[Mike82ndABN]

So yea back on topic. My hmmwv has radials and 12 bolt rims. What are you guys running, 25 to 30 psi ?

 

[jadatis]

Then you still have to give me more information, see my first post in this topic and forum.

 

[Mike82ndABN]

Why would you need my information to tell me what you run in your tires. Sounds crazy.