tire pressure ????

logan97 · Jan 26, 2010

while checking the tire pressure on my newly acquired B7800 the rears had 8 on one side and 5 on the other there is also fluid in them. I got the stems at 12 0'clock and re-checked yet the fluid still comes out when the gauge is put on.Will they accept air or does some of the fluid need drained? The manual says do not fill tires more than 75% with the valve stem at 12 0'clock. If I have to drain some liquid is this stuff toxic? it has not froze in the last cold spell. Recommended inflation pressure 16 back,22 front the manual does not mention pressure when ballast is in them. what would be a safe pressure with the ballast ? What size compressor is needed to get up to pressure?

gwdixon · Jan 26, 2010

Pressure is pressure. Since water is not compressed the pressure should be the same as specified in the manual, filled or not.

There may have been liquid left in the valve stem that squirted out when it was put at 12 o'clock. If the tire takes air, which it should given the pressures they are at now, then all is well. You could bleed all of the air out and then refill if it makes you nervous. That way you would know if there was air in the tire originally.

Since water expands when it freezes and water does not compress that is the reason the tires should not be filled with 100% water. The air gives it some space for wiggle room.

Any compressor will work that will make 22 pounds. It may take longer with a small compressor but otherwise no problem.

There are several different fills that can be used in tires. Don't drink any of them.

The front tires should not be filled especially if you have a FEL.

DanD78 · Jan 27, 2010

I would bleed air out of the rears with the valve stems straight up until fluid stops then check the pressure. I think you will find that 22 in the rears will be way too much. I sould guess in the 10~12 range. Drive a wet tire over concrete and look at the print it leaves behind. If it only touches in he center you have too much air for the weight you have on the back at the time.

I fill the front tires on all my small tractors even with a loader. I have even filled skid steer tires. Like said before, Pressure is pressure. I have never had one pop off the bead but i also blow them up to the top range for the tire.

Dan

BXpanded · Jan 27, 2010

Don't bother to bleed the fluid. It's pretty difficult to get much more than a 75% fill even if you're trying and most people don't try that hard. Air it up to whatever pressure you want with any compressor. I like to keep the pressure fairly low on filled tires as the ride is a bit better.

Remember, if you start to let the fluid out of the tire, it starts to go flat ON THE BOTTOM pushing the fluid higher in the tire. You'll end up letting out fluid until the tire is completely flat. When you refill to pressure with air, the tire may be only 30% filled.

If you decide you really want to make sure the fluid is not above the valve at TDC, inflate the tire somewhat above the desired presssure then let out some fluid to drop the pressure to your intended final pressure. Re-inflate and repeat until no more fluid comes out.

radioman · Jan 27, 2010

Are you sure you are overfilled ? or stem has stuff still in it causing to be overspray? I would move stem to 12ish oclock position and then give it a shot of air to push fluid in away from stem. Then its a best way to check the pressure. I noticed after I had fluid added to tires, and inflate to recommnded pressure, it has a hump in tire. I let nearly 10lbs out and it was much better ride and more surface for best traction.

Baby Grand · Jan 28, 2010

I think BXpanded is on the right track:

Remember, if you start to let the fluid out of the tire, it starts to go flat ON THE BOTTOM pushing the fluid higher in the tire. You'll end up letting out fluid until the tire is completely flat. When you refill to pressure with air, the tire may be only 30% filled.

As a check, you can jack up the axle enough to get the tire off the ground and have the valve stem at about 12 o'clock, you should be able to bleed off the valve without draining any fluid other than a bit of spray from what's left in the valve stem.

Turn the wheel until the valve is about where you want the fluid level, drain any fluid that is still above the valve and then air up. Recheck pressure when you've got the wheel on the ground.

-Jim

gwdixon · Jan 28, 2010

If the valve is on the top, at 12 o'clock, then the tire is let go flat it will only flatten to the rim on the bottom. Any extra would drain out the valve through the top. There would be no additional collapsing of the tire.

Then filling the valve with air to the desired pressure should be pretty close to a good air/water mixture - maybe a bit less than 60% because the valve is at the top of the rim rather than at the top of the tire.

Baby Grand's idea of jacking up the tire and letting out all of the air with the valve at 12 o'clock makes sense. Just visually, it would appear that at that position the rest of the tire is about 75% below the valve and would be perfect to just fill it with air from that point.

Maybe someone who has seen a dealer fill a tire or had a tire repaired and refilled can chime in on how the refill process is done. I have seen a special valve attachment that is used to fill tires but have no experience with it.

art · Jan 28, 2010

The pumps we use today will over fill a tire although it normally is not done to an extreme if the operator is paying attention. To have them much over 75% is a lot of work to do!

Front tires with a loader, run them at the max air recommended, rears a poster above told of the full foot print technique for the optimum traction.

bstrom · Jan 28, 2010

My recommended tire pressure was 20 lbs rear. After the dealer filled them with rimguard he told me they were filled to 75% and set at 14 lbs, so I think you definitely want less air after they are filled. Mine were off the tractor when they were filled. When I put them back on and went to check the pressure, the beet juice came out and made a mess of my gauge even with the stem at 12:00. I think that is because the weight of the tractor was pushing the fluid up so I think it is a good idea to jack up the tractor before checking the pressure as a poster did previously mention. I haven't tried it yet though.