Views: 0 Author: Site Editor Publish Time: 2025-12-15 Origin: Site
Reading a load chart is one of the fastest ways to reduce risk, prevent overloads, and make confident lift decisions—especially on a Truck Mounted Crane, where capacity can change dramatically with outrigger position, boom length, and working radius. This guide breaks down how to read a truck mounted hydraulic crane load chart in minutes using a simple, repeatable workflow you can apply on real jobsites.
What you’ll get: a practical “3-step method,” a worked example, common mistakes to avoid, and a platform-by-platform view of how different training and industry sources describe load chart reading.
A load chart is not just a table of numbers—it’s a set of operating limits tied to a specific crane configuration. It tells you the maximum rated load the crane can lift under defined conditions. Those conditions usually include:
Outrigger / stabilizer setup (fully or partially extended)
Boom length and boom angle
Working radius (distance from the crane’s rotation center to the load’s center)
Attachments (jib, fly, hook block type, winch line, etc.)
Any special restrictions (in-motion ratings, wind limits, side loading restrictions)
Most Truck Mounted Crane charts include these elements:
Load Ratings Table: capacity values based on boom length and working radius.
Range / Working Area Diagram: a reach map that shows height vs radius across boom angles/lengths.
Notes & Limits: the “fine print” that controls how you must interpret the numbers.
Rated (Gross) Capacity: the capacity shown in the table before subtracting lifting gear and line components.
Net Capacity: your real allowable load after deductions (hook block, rigging, etc.).
Working Radius: the horizontal distance from the crane’s center of rotation to the load center.
Boom Length / Extension: the boom’s deployed length used for the chart column.
Boom Angle: the angle of the boom (some charts list “loaded boom angle”).
Outrigger Setup: the stabilizer spread/condition that determines which chart applies.
The fastest reliable approach is a 3-step workflow: match the configuration, lock the working position, then convert gross to net. If you follow this order, you avoid the two biggest errors: reading the wrong chart and skipping deductions.
Before you look at any capacity number, confirm you’re reading the chart for the exact crane and setup you’re using:
Crane model and the correct chart series (manufacturer often publishes multiple pages).
Outriggers/stabilizers: fully extended, intermediate, or retracted—this matters a lot.
Attachments: jib/fly installed or stowed, auxiliary hook, etc.
Reeving/parts-of-line requirements (some loads require multiple falls).
Operating mode: on outriggers vs “on rubber,” creep, or in-motion limits (if your crane provides them).
Minute-saver: if your crane setup doesn’t match the chart page exactly, stop and find the correct page first. Reading the “closest” chart is how overload events happen.
Once you have the correct chart, determine the crane’s working position. You need two things:
Working radius at the lift point (pick and set locations can differ).
Required height / reach to confirm the boom can physically reach the placement point.
Working radius is not simply “distance from the truck.” It’s measured from the crane’s center of rotation to the load’s center when the load is hanging. You can estimate it using:
Jobsite measurement (tape/laser), or
Lift plan geometry, or
The range diagram if you know boom length and angle
The range diagram acts like a reality check: it shows whether your chosen boom length/angle can reach the required height at the necessary radius. If the diagram says you can’t physically reach the point, the capacity table doesn’t matter yet.
Now you’re ready for the table.
Most tables are set up like this:
Radius (rows) down the side
Boom length / extension (columns) across the top
Capacity (cells) at the intersection
Find your radius row, find your boom length column, then read the number where they meet.
Your allowed lifted load is usually less than the number shown because you must subtract weights that the crane is also supporting. Typical deductions include:
Hook block or headache ball
Slings, shackles, spreader bars
Any auxiliary lifting devices attached to the hook
Stowed jib/fly components if the chart requires deduction for them
Multipart blocks or additional line components where specified
Rule of thumb: if it hangs from the hook or is supported by the crane during the lift, it usually counts in the lifted weight. Your goal is a conservative, defensible net number.
Between radii: use the more conservative (lower) capacity—don’t interpolate unless the manufacturer explicitly allows it.
Boom length not listed: use the next longer length or follow manufacturer instructions (longer boom often reduces capacity).
Angle differences: if the chart references loaded boom angle, confirm your working angle aligns with the range diagram and note requirements.
Below is a generic example to show the workflow. Use your manufacturer’s numbers—not these placeholders.
Crane: Truck Mounted Crane on fully extended outriggers
Task: lift a packaged unit from a staging area and set it onto a platform
Pick radius: 8 m
Set radius: 10 m (farther because of swing/placement)
Required hook height: 12 m at set point
Rigging + hook block: total 0.35 t (example deduction)
Select the chart page that explicitly states: fully extended outriggers, no fly jib installed (or fly installed if it is), and the correct reeving mode for your line.
Confirm that your intended boom length and angle can reach 12 m at 10 m radius. If not, adjust boom configuration (or reposition the truck) before reading capacity.
Use the set radius (10 m) for the controlling capacity because it’s the larger radius. In the load table, find:
Row: 10 m radius
Column: your chosen boom length
Cell value: Rated (gross) capacity at that condition
Then compute net allowable load:
Net capacity = Rated capacity − (hook block + rigging + lifting devices)
If your net allowable load is still comfortably above the load’s verified weight (including packaging and any handling frame), the chart side is acceptable—then you continue with site checks, ground conditions, and lift planning requirements.
On a truck mounted hydraulic crane, outrigger spread can be the difference between a safe lift and a rejected lift. Load charts typically assume a specified outrigger condition and ground support. In practice:
Ensure outrigger pads are appropriate and placed correctly
Confirm ground bearing is sufficient (especially near trenches, backfilled areas, or soft soil)
Keep the truck level within manufacturer limits—small tilts can reduce stability margin
Boom Truck (telescopic) charts: table-based ratings plus a range diagram.
Loader crane / knuckleboom diagrams: graph-style reach vs load curves or zones.
The reading logic is similar: match configuration, determine radius/reach, then use the correct value for the operating position and apply any required deductions.
Many charts include cues (such as bold lines, footnotes, or specific annotations) to differentiate between:
Stability-limited zones (where tipping is the controlling factor)
Structure-limited zones (where boom/structure strength is the controlling factor)
For day-to-day decisions, you don’t need to debate which limit applies—you need to follow the chart’s rules and notes exactly. But recognizing the concept helps you understand why capacity can drop sharply as radius increases.
Fix: confirm outrigger setup, attachments, and operating mode first. If anything changes, re-check the chart page.
Fix: radius is measured from rotation center to load center under load. Measure it or derive it from your lift plan and range diagram.
Fix: use a standard deductions checklist. If your team uses common rigging sets, pre-weigh and label them so you can subtract quickly.
Fix: if your Truck Mounted Crane has different ratings for stationary vs moving, treat moving ratings as a separate chart with stricter limits.
Fix: the largest radius during the lift usually controls—often the set radius, sometimes during swing or booming down.
In many practical training approaches, you can solve chart reading quickly if you know any two of the following:
Boom length
Working radius
Hook height / reach
Use the range diagram to determine the missing value, then read the table and apply deductions.
This prevents wasted time. If your chosen configuration can’t physically reach the set point, there’s no reason to argue about table capacity yet.
Create a small reference list for your most common hook blocks, shackles, slings, and spreader bars. When you can subtract deductions in seconds, your load chart read becomes genuinely fast.
SANY Global: Focuses on reading the chart as a structured process—confirming the operating configuration, locating the correct capacity point, and accounting for deductions to determine what can be safely lifted under that setup.
Heavy Equipment College: Emphasizes that load charts are variable-driven documents, highlighting how radius and boom conditions change allowable load and why operators must understand the chart to work safely and pass training/certification expectations.
American Crane School: Explains the table layout and how operators use radius and boom length to locate capacity, while drawing attention to angle-related information (including loaded boom angle) when it appears on charts.
LaGrange Crane: Highlights the importance of combining the range diagram with the capacity table—using boom geometry to confirm reach and then reading the intersection values that define capacity at a given operating condition.
Bigge: Breaks load chart reading into major components—capacity table, range diagram, the influence of jib/fly and lift angle, and the key operational distinction between stationary lifting and in-motion or creep limits where applicable.
Elliott Equipment: Stresses that boom-truck charts must be read with attention to chart notes, including stability/structural cues and required deductions, and reminds operators that on-the-hook components reduce what you can safely lift.
Atlas Polar: Frames HIAB-style load diagrams as graphical interpretations of crane capability over reach positions and reinforces that correct diagram interpretation is a core operator competency for safe work.
Facebook crane community: Discusses load charts as the primary reference for deciding allowable load at a specific radius and configuration, reinforcing the practical, on-the-ground importance of reading the correct chart under real conditions.
Reddit r/cranes discussion: Shares practical operator viewpoints on common confusion points—especially what must be counted in deductions and how accessory choices and reeving details can affect chart-based decisions.
Gross (rated) capacity is the value shown in the chart for a specific radius and boom condition. Net capacity is what remains after subtracting the weight of the hook block, rigging, and any lifting devices supported by the crane.
Markings often indicate different limiting conditions or zones. The practical takeaway is to follow the chart notes associated with those markings and treat them as operating boundaries.
Unless the manufacturer explicitly allows it, use the more conservative option. Most field best practices treat “between values” as a reason to round down capacity.
Not necessarily. If your truck mounted hydraulic crane provides separate in-motion/creep ratings, those are different limits and are often more restrictive.
At minimum, deduct the hook block or ball and your rigging (slings, shackles, spreader bars). If the chart notes specify other deductions (like stowed components), include them too.
Rated Capacity: the table value under a specified configuration.
Net Capacity: rated capacity minus deductions.
Deductions: weights supported by the crane besides the load.
Working Radius: distance from crane rotation center to load center.
Boom Angle: boom inclination (sometimes “loaded boom angle”).
Outriggers/Stabilizers: supports that widen the base and increase stability.
Parts of Line: number of rope falls supporting the hook block.
Bottom line: To read a load chart on a Truck Mounted Crane in minutes, lock the configuration first, confirm the working radius and reach with the range diagram, then read rated capacity and subtract deductions to get net allowable load. Repeat this process at the pick and set points, and always use the worst-case radius as the controlling condition.
