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Retarding performance, Gross weight – Milton CAT 777F User Manual

Page 23

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23

777F Off-Highway Truck specifications

0

10

20

30

40

50

60

70

80

0

5

10

15

20

25

30

35

40

45

50

0

50

lb x 1000

mph

km/h

15%

Speed

Continuous Grade Length

Effective Grade

(Grade Minus Rolling Resistance)

0

30

60

90

120

150

180

210

240 kg x 1000

Gross Weight

1st Gear

5%

10%

100

150

200

250

300

350

400

450

500

4th Gear

5th Gear

6th Gear

30%

2nd Gear

3rd Gear

25%

20%

E

L

7th Gear

To determine retarding performance: Add lengths of all
downhill segments and, using this total, refer to proper
retarding chart. Read from gross weight down to the percent
effective grade. Effective grade equals actual % grade minus
1% for each 10 kg/t (20 lb/ton) of rolling resistance. From this
weight-effective grade point, read horizontally to the curve
with the highest obtainable gear, then down to maximum
descent speed brakes can properly handle without exceeding

cooling capacity. The following charts are based on these
conditions: 32

° C (90° F) ambient temperature, at sea level,

with 27.00 R49 tires.

NOTE: Select the proper gear to maintain engine rpm at the highest
possible level, without overspeeding the engine. If cooling oil
overheats, reduce ground speed to allow transmission to shift to
the next lower speed range.

Retarding Performance

With ARC Only
ARC and Engine Brake

E – Typical Field Empty Weight
L – Target Gross Machine Operating Weight 163 293 kg (360,000 lb)