Tires Filled Rear Tires

[allpontiac]

Really nice day here in NC - got the Ford New Holland 1715 out and did some work on my building site. After reading some of the threads here, checked the torque on my lug nuts - three of the four wheels were loose. Only had the tractor for two months so decided to check the air pressure in the tires - front ok but to my surprise, the rear tires are filled. No wonder the FEL has been working so well!. So my question is do I adjust the air pressure to compensate for the water or go with the factory recommendations. Put the valve stem on top to check pressure but still get water - what is the proper procedure for checking air pressure on a filled tire? Thanks, Lewis

 

[JD3130]

You need to check your manual or with the dealer. From my JD manual the tires on mine should not be that full?? When the stem is at the top, they should be above the fluid.
PS. If you get freezing weather there I hope to heck you have the correct mixture in them? Psi is the same.

 

[RoyJackson]

You should take the weight off the rear tires when you check the pressure. Then the valve stem should be at the 12 O'Clock position. If you still get fluid coming out, they're overfilled.
I can't tell you where to jack your tractor, but I put a floor jack under the draw bar bracket of my 790.
BTW, you need an air/liquid pressure gage for this. They look just like a regular pressure gage but have a spring loaded measurement stem that pushes the fluid back out.

 

[sherpa]

Where do you live in NC, I live in Mortimer, NC.
Sherpa

 

[btolle]

Nothing is ever as simple as it seems. See the Fiirestone Agricultural Tire Data website for more information than you ever wanted to know about ag tires.

BTW, if you read the inflation data on the side of the tire it will say somethng like "Max inflation pressure XX pounds at XXXX pounds of load" or something to that effect. That is not necessarily the correct pressure for a particular tractor.

To be **** about it (and I am on my Jeep and motorhome) you would have to weigh the tractor front and rear and then use an inflation table to ascertain the correct inflation pressure. The more weight, the more pressure is needed.

With filled tires you need to adjust the inflation tables to account for the weight of the fill. I can't remember the formula but I posted information about that a month or so ago and can't seem to find my reference at the moment.

While inflation tables are one guide, another way to determine optimum pressure is at University of Missouri tire information It tells you how to determine the optimum tire pressure for a given implement by driving the tractor until the rear wheels make 20 revolutions with the implement in the ground, then drive it with the implement NOT in the ground and use a formula to determine the amount of slip. A tractor tire should actually slip about 10% for optimum performance.

As a practical matter, I adjust my tire pressure so that NEARLY the entire tread lays flat on the ground when parked on concrete, that seems to give me the best traction/ride combination which happens to be 10 or 15 pounds less than the maximum inflation pressure shown on the tire.

At the maximum pressure (which was what the dealer had them at when I picked it up) it beat me to pieces with the rough ride and the tires slipped excessively in my soil conditions.

Bill Tolle

 

[tomrscott]

Anybody know which of the tires at that Firestone site equate to what we would call an R4 on a CUT? There are so many different Firestone varieties it is complicated. They don't seem to be grouped by R1, R4, etc.

 

[allpontiac]

Thanks everyone for the info - I am suprised at how much is involved but will get an air/liquid gauge and start there. SHERPA, I live in Mooresville on Lake Norman about 30 miles northwest of Charlotte. Will soon be building a new house on Highway 152 about half way between Mooresville and China Grove. Have 6.25 acres of woods there and am now clearing an area for the house.

 

[sherpa]

allpontiac
Yea I know where Mooresville is. I used to live in Hickory. You are there in Nascar country. I have a part time neighbor up here that lives on Lake Norman. I am way back in the mountains under Blowing Rock.
Sherpa

 

[btolle]

</font><font color="blue" class="small">( Anybody know which of the tires at that Firestone site equate to what we would call an R4 on a CUT? There are so many different Firestone varieties it is complicated. They don't seem to be grouped by R1, R4, etc. )</font>

Look in the Industrial tires section. Firestone seems to think R4's are only for skid steers.

Bill Tolle

 

[bugstruck]

According to my manual the inflation pressure on R4 420/70-24 6PR tires is 20 psi. with no liquid. They also instruct as Roy posted earlier that no fluid should be present above the valve at 12 O'Clock position. My dealer advised I run my fluid filled tires at 8 to 12 psi with 10 to 12 used most often. You need an air cavity in the tire for compression over obstacles (deformation). Fluid won't compress. Stands to reason the pressure would be somewhat lower on a filled tire as less air cavity means less available compression zone. My R4's look and feel right so far at the dealer recommend/set pressure. With my backhoe on the lugs are making full contact (edge to edge) on a flat surface with no discernable sidewall bulge. I haven't looked that close with the hoe off but I imagine the outer edges of the lugs are off the floor somewhat without the hoe.

The dealer advised they don't have a set pressure rule like the manufacturer. They inflate according to each situtation being careful not to exceed the max. psi. It's more a visual thing. My salesman is a former farmer and he said nothing beats sticking you finger between lugs and moving them up (tire to floor) and down once you think you have the inflation right (visually). You can feel the amount of movement on R1 and R4 tires. He advised that the visual and finger method is how they dial them in and just use the gauge for equalizing. Tire wear over time is a factor on the finger method. Not very scientific but mine are right. Seems to work.

My be worth a shot.

Good Luck,