Caterpillar 24 Motor Grader
The largest motor grader Caterpillar builds, sized specifically to maintain the wide haul roads inside a mine rather than the narrower roads a construction grader typically finishes.
Overall height, top of cab: 4.5 m — about 2.5× an average adult's height (1.8 m). The machine is always drawn at the same size here; the human figure is what actually scales.
01Overview
The largest motor grader Caterpillar builds, sized specifically to maintain the wide haul roads inside a mine rather than the narrower roads a construction grader typically finishes.
02Purpose
Exists to keep haul roads within the tight tolerance mine-truck tyres depend on — a job that pays for the machine's size many times over in extended tyre life alone.
03Historical Development
Motor graders scaled up specifically to keep pace with the haul roads mining trucks depend on: a rutted or poorly cambered haul road wears tyres and suspension components on every truck that crosses it, all day, so a grader capable of maintaining a very wide road in fewer passes pays for its size many times over. Caterpillar's 24-class graders have occupied the top of that size range for decades.
04Core Components
- Long wheelbase frameStretched well beyond a construction grader's frame to keep the blade stable and the cut accurate across a wide haul road.
- Circle & drawbarThe rotating ring beneath the frame that lets the blade angle, tilt, and sideshift independently of the machine's direction of travel.
- Moldboard (blade)A blade roughly 24 feet long, the machine's namesake, that shapes and smooths the road surface in a single pass.
- Articulated or rigid frame steeringAllows precise, repeatable steering control critical to maintaining a consistent road crown.
05How It Works
Hydraulic cylinders rotate the circle beneath the frame to set the blade's angle relative to the direction of travel, then tilt and raise or lower it to the cutting depth the operator wants. As the grader moves forward, the angled blade shears off high spots and redistributes material into low spots and the road's crown, restoring the smooth, correctly cambered surface that keeps water shedding off the road instead of pooling and softening it.
06Engineering Principles
The powershift transmission's gear steps are tuned for the narrow, steady speed range grading actually requires, unlike a haul truck's broad speed range.
HydraulicsHydraulic CylindersEvery blade movement — angle, tilt, sideshift, lift — is driven by a dedicated hydraulic cylinder acting on the circle and drawbar.
Power TransmissionBearingsThe circle itself rides on a large-diameter bearing race that has to stay precise under constant vibration and dust for the blade angle to hold true.
07Performance Characteristics
| Operating weight | ~65.8 t |
| Blade length | 24 ft (7.3 m) |
| Wheelbase | ~7.9 m |
| Typical role | Mine haul-road maintenance |
08Notable Examples
- Major open-pit haul road networks worldwide24M-class graders run scheduled maintenance passes to keep haul roads within the tight tolerances mine-truck tyre life depends on.
09Interesting Facts
- A well-maintained haul road can double the useful tyre life of every truck that runs on it — which is why a mine will run a grader this large purely on road upkeep, never digging anything itself.
- Its blade can shift, tilt, and angle independently, letting one pass both cut a crown and cast material toward the road's edge.
- Despite its size, fine control is the point: a grader operator is expected to hold the blade within centimetres of a target grade all day.