82.3-0000010 OM
76
3.2.8.2 Methods for selecting the optimal internal pressure in tires, depending on
working conditions and load on the tractor axle. Variants of tractor front and rear tire com-
binations
Tractor tire pressure must be selected using the tire manufacturer's information ta-
bles with a predetermined effective wheel load and tractor speed.
The tables for permissible loads, speeds and tire pressures vary depending on the
tire size and tire manufacturer. There is no universal range of tire loads, speeds and pres-
sures, that suits all tire manufacturers. The load characteristics shall only be considered
with regard to the particular tire manufacturer.
Determining the optimal internal tire pressure is achieved by actual weighing of the
tractor with the implement on a motor vehicle scale.
The procedure for selecting the tire pressure in tractors "BELARUS-82.3" is as fol-
lows:
I) Measure the load on a single axle of the tractor with the implement by weighing.
When weighing, the following conditions must be observed:
(a) If equipment is attached to the tractor's RLL and there are no front weights, then:
- the front axle is weighed (with the RLL lowered);
- rear axle is weighed (with RLL lifted).
b) If a tractor is equipped with front weights and there is no equipment on the RLL,
then:
- the front axle is weighed (the RLL position is irrelevant);
- the rear axle is weighed (the RLL position is irrelevant).
c) If the tractor is equipped with front weights and there is equipment on the RLL,
then:
- the front axle is weighed (with the RLL lifted);
- the rear axle is weighed (with the RLL lifted).
d) If there is no equipment on the tractor's RLL and no front weights, both front axle
and rear axle are weighed with any position of the RLL.
II) The load on a particular wheel is determined by dividing by two the load value of
the tractor's front or rear axle, respectively. Then, on the basis of the specific load and
speed, the tire pressure is selected according to the tire manufacturer's table of loads and
pressures.
Example of selection of wheel tire pressure is shown in Figure 3.2.2. Tables of
loads, speeds and pressures in tires should be read starting from the tractor travel
speed 1, at which the agricultural operation will be performed. According to the line asso-
ciated with the speed, find the permissible load on the tire 2, which must exceed the value
of the current load on the front or on the rear tractor axle, divided by two. Then use the ar-
row to go up to the corresponding value of air pressure in tire 3.
Figure 3.2.2 – Example of selection of wheel tire pressure
The tire pressure selected in accordance with the table in Figure 3.2.2 is the minimum
pressure and should only be used as a guidance. In case of pressure increase, from mini-
mum pressure and above, it must not exceed the maximum permissible pressure according
to the table in Figure 3.2.2 (in this case not more than 160 kPa at a speed of 30 km/h). All
tire pressure readings refer to a "cold" tire that has been outdoors for several hours.
km\h
Load on tire, kg, at internal pressure, kPa
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