Proper tire pressure?

2dawoodz · Jan 31, 2011

Checked a friend's tire pressure on his Ford NH 1920. Front was 21 and rear was 6 & 8 psi. Rear seems low to me but little sidewall deflection. Not sure how much sidewall deflection I should be seeing. Owner does not have a manual. Thanks.

Soundguy · Jan 31, 2011

rear tires generally run lower psi... as a rule of thumb i air them up till the look good in profile. it's a bit of a compromise between tire patch, traction and were pattern.. also have to consider load carried and bulge.

i don't even use an air gage anymore. just air em up till the 'look' correct.

i know there's a science to it.. but you can do it like it's an art and it works out just as good..

soundguy

nickel plate · Jan 31, 2011

I keep my tires, all 29 of them

including the wheel barrow eyeballed below but near the range of the max PSI stamped on the tire casing.

Reg · Jan 31, 2011

A lot depends on whether or not there is a LOADER.
Over 40 psi is not uncommon for R4s on tractors with loaders.

The Firestone web site has/had a load/pressure table for just about every tractor tire.
The max pressure molded into the sidewall is only suitable for max load - generally a bad idea to run at that pressure, also a bad idea to be loaded at or close to the max anyway.
For field work you generally want drive tires "a bit squishy" {a very precise technical term}
You can read the soil to detect slippage - it takes practice (-:

638 · Jan 31, 2011

I run my BX rear tires so that I have full tread on the ground when I'm on concrete. Fronts are at or near max presure because of the front loader.

SandburRanch · Feb 1, 2011

I would caution anyone working on inclines about just eyeballing and guessing at tire pressures. Old tires that have hardened over the years don't show sidewall squat as well as newer tires.

Did the tractor roll over because the tire bead broke from the rim or did the roll over cause it to break away. If the operator is dead the investigating team may never know. I've used both eyeball and gauge methods and in my younger days I've even kicked a tire or two but in later years I prefer the gauge. It doesn't hurt my toe so bad.

2dawoodz · Feb 1, 2011

This tractor does have a front loader and 4x4 ability. I just wasn't sure about running max pressure like I do in my street vehicles. Thanks for everyone's input!

jimmysisson · Feb 1, 2011

Seem to remember an old rule of thumb with ag tires was one bar on the ground and two others touching. I'd guess that at maybe 10 #??
Jim

Soundguy · Feb 2, 2011

imho.. if the side angle is soo bad that a couple inch drops makes for a roll condition.. you already don't need to be on that side angle.

soundguy

SandburRanch said:
I would caution anyone working on inclines about just eyeballing and guessing at tire pressures. Old tires that have hardened over the years don't show sidewall squat as well as newer tires.

Did the tractor roll over because the tire bead broke from the rim or did the roll over cause it to break away. If the operator is dead the investigating team may never know. I've used both eyeball and gauge methods and in my younger days I've even kicked a tire or two but in later years I prefer the gauge. It doesn't hurt my toe so bad.