Question about rear tire air pressure

[catalina0029]

I am new to this so pardon the stupid question.
I have a '64 4000 gas.The rear tires are brand new Firestone Traction Field & Road 13.6 x 28. The tire says not to exceed 35 psi when setting the bead. The specs on the web for the tire says 42 psi Max.

Max Single Air Pressure(PSI) 42 The maximum air pressure this tire will support. This does not represent the amount of air pressure your tires should have at all times. Consult with your owner's manual to determine the best air pressure you should use for your vehicle.

I've looked in the owners manual. I do not plan on filling the tires with liquid. What should I run for air pressure?
I plan on running a 5' brush cutter and a finish mower.

 

[showcrop]

I would start at 10 lbs since there is no load being carried.. You will be told that you want the bottom 2/3 lugs to be flat if on pavement but that will give you a lot more "squat" than you want.

 

[flatpkr]

Id put in 20 lbs and see how the tire sits on the ground, you want just a slight podding out of the tire on the ground. Put in more or less as needed to
get that slight podding out of the tire.
Jim

 

[SVcummins]

Why wouldnt he want more floatation

 

[SVcummins]

 

[grizz02]

An AG tire is not a car or truck tire you want to try to get 3 bars on the dirt at the bottom so 10 to 12 lbs usually does the
trick , you want the tire at the bottom to be bulged out a little when you look from the rear

 

[Jim.ME]

(quoted from post at 13:25:57 03/21/21) I am new to this so pardon the stupid question.
I have a '64 4000 gas.The rear tires are brand new Firestone Traction Field & Road 13.6 x 28. The tire says not to exceed 35 psi when setting the bead. The specs on the web for the tire says 42 psi Max.

Max Single Air Pressure(PSI) 42 The maximum air pressure this tire will support. This does not represent the amount of air pressure your tires should have at all times. Consult with your owner's manual to determine the best air pressure you should use for your vehicle.

I've looked in the owners manual. I do not plan on filling the tires with liquid. What should I run for air pressure?
I plan on running a 5' brush cutter and a finish mower.

Pressure for seating the beads is not the same as the operating pressure. "Seating the beads" is getting the beads out into the position they belong at on the rim during installation. It is not unusual for the beads to be in away from the rim flanges when first installed. Then when you first apply air, the beads move out to the rim flanges. The recommendation is that you do not use more than 35 PSI to get them out to the flanges. If more is required they may need some lube or they are not installed correctly, wrong size, etc. -- something is wrong. Once they are seated you inflate to operating pressure.

 

[SVcummins]

I run 22 psi when carrying my lely on single tires it weighs
3000 pounds 3020 has 15.5.38 tries

 

[Case Nutty 1660]

16 lbs min for your size tires, if carrying some thing really heavy up to 18 psi no more, running less is very hard on sidewalls,, especially with today's tire compounds, only thing I run 10 psi in are my outside duals 20 psi on the inside on the tractor in the pic

 

[SVcummins]

Are they different size ? I. Sure hope thats not a recent picture

 

[diesel fumes]

ditto with sv cummins; that chart is a very good reference point. you want a barely noticeable bulge looking at it on solid flat surface

 

[Bruce from Can.]

Less pressure, softer ride.

 

[RobCons]

I've got a 1963 model 4000 with the same size tires. I have about 12 lbs in them and it does fine.

 

[casecollectorsc]

For normal operation the dealers here say 1 pound for every inch of width. For your tire I would run 13-14 psi. 20 psi on that size
tire would have it round on the bottom instead of flat. The tire should have good ground contact for maximum traction. Another example
is a 18.4x 34 tire runs 18 psi....simple.

 

[Case Nutty 1660]

taken yesterday why and yes all are the same size might be the angle

 

[Case Nutty 1660]

 

[SVcummins]

I have to run my pressure that way on my 3020 duals because the insides are new and the outsides are about 25% tread . That is dry for March

 

[Case Nutty 1660]

We are still in a drought,, I have never ran duals on my 2whl drives with the same air,, they ride like they ave steel wheels and it is very hard to things doing so,, I am planting in good H20 at the moment,, and we got 2 plus of nice wet snow yesterday,, hopefully we keep getting some as we go along

This was all melted and soaked right in the ground by 10 am yesterday

 

[Texasmark1]

I drive up on a concrete floor. Adjust the air pressure so that the edge of the lug just touches the floor, from an air pressure that raises the edge
off the floor (ballooned). Results are a few # less than the normal rated 18 psi....with max 35 # seating rating for my tires of that size.

 

[sotxbill]

ON bias belted tires.... air up just till the bulge JUST goes away, but as others have said... the bottom cleats are flat on the ground.

This will be very delicate as.. a bit low and you have sidewall bulge and will cause cracks in the sidewalls. Too high and the cleats will not lay flat and you will loss traction and if a bit more, the center of the tread will crack early. Especially on these new import tires from he77. They will crack like crazy.


Radials not usually used on smaller tractors but will almost always have a bulge as they flex differently.

As an old farmer said... "Bias tires MIGHT give you two lugs on the ground, where a radial can give you three lugs on the ground easily."