How to Choose the Right Tower Crane for Your Construction Project in Kenya: Load Charts Explained
The brochure sells maximum capacity; the site demands capacity at radius. Learn to read a tower crane load chart in ten minutes — and size the crane your project actually needs.
1. The Load Chart Is the Crane
Two cranes can share a mast height, a paint job and a brochure — and differ by half their working capacity, because the load chart is the machine's real specification. Everything else is geometry and electrics. A tower crane lifts by resisting moment — the load's weight multiplied by its horizontal distance from the mast — and the load chart is the manufacturer's map of exactly how much moment the structure can resist at every radius, jib length and height. This guide teaches the ten-minute literacy that separates a correctly sized crane from an expensive disappointment, from the team behind our services — Trust Partners Geo-Group, whose crane desk sizes machines from load schedules every week.
2. Anatomy of a Load Chart
A tower crane load chart reads like a mileage table:
- The axes: radius in metres along one side — the horizontal distance from the crane's centre to the hook — against jib length or configuration along the other.
- The cells: the crane's capacity in tonnes at each combination. The top-left corner holds the headline maximum — capacity at minimum radius; the far-right column holds the tip capacity at full jib, the number that governs edge-of-site lifts.
- The fall: capacity drops roughly linearly with radius — each additional metre of reach costs capacity, because moment grows while the structure's resistance stays fixed.
- The footnotes: height-dependent values on multi-fall reeving, in-service and out-of-service wind speeds, and the deduction for rigging — the fine print where lifts are actually won or lost.
3. Reading the Numbers: Worked Examples
| Radius | 8t Flat-Top, 60m Jib (illustrative) | Typical Lift at That Radius |
|---|---|---|
| 15 m | ~8.0 t | Precast panels, steel bundles |
| 25 m | ~6.0 t | Formwork tables, rebar cages |
| 40 m | ~4.0 t | Blockwork pallets, scaffold loads |
| 50 m | ~2.8 t | Light distribution, waste skips |
| 60 m (tip) | ~2.0 t | Edge-of-site material only |
Three readings from the table. Read one: a 3.5-tonne panel at 40 metres clears the 8-tonne class comfortably — but the same panel at the 55-metre far corner does not; the jib or the crane class must change. Read two: rigging deducts real capacity — a 200kg spreader and slings turn a 2.0-tonne tip limit into a 1.8-tonne load limit. Read three: the chart applies to the crane as erected — a jib shortened for a tight site has a different chart from the brochure configuration. Our tower crane rental desk supplies the correct chart with every quotation, matched to the machine and the configuration.
4. The Four Inputs That Size the Crane
- Heaviest single lift — the maximum load, plus rigging, the crane must ever pick. Not the average: the worst hour of the programme.
- Maximum radius — the farthest working point from the crane's position across the site plan. This sets jib length, and through the chart, the capacity class.
- Hook height — tallest pour, plus rigging, plus clearance. This sets mast height and predicts the climb count.
- Duty cycle — lifts per hour, sustained. High-frequency precast or blockwork cycles demand a heavier class than the same weights at leisure pace.
💡 The worked example
A mid-rise frame: heaviest pick 3.5 tonnes (with rigging), farthest point 45 metres, hook height 42 metres, moderate duty. Chart requirement: ≥4 tonnes at 45m with margin — which lands in the 8-tonne flat-top class on a 60m jib, two climbing sections, one crane position. Every selection resolves this way: four inputs in, chart requirement out, class named.
5. Common Selection Mistakes
- Sizing from the brochure maximum — the 8-tonne headline is at 15 metres; the site lives at 40–60.
- Ignoring radius growth — a crane positioned for the first pour may be wrong for the far wing; position and jib are chosen together, from the whole plan.
- Forgetting rigging — slings, spreaders and grabs eat capacity on every single lift.
- Wrong duty assumption — a crane perfect for steel erection may overheat on a precast cycle; class the duty, not just the weight.
- Height myopia — the crane that reaches floor twelve today must climb twice before floor twenty; climbs change the chart and the programme.
6. The Selection Workflow
- List every significant load: weight, pick-up radius, landing radius.
- Mark the crane position options on the site plan; test one position against the whole building before adding machines.
- Convert each load to a chart requirement with 10–20% margin; the controlling load is the one that demands the most crane.
- Name the class and jib; check hook height and climb count; confirm the base suits the position.
- Verify duty class and wind exposure; then price the engagement — the cost estimate calculator takes crane class, jib and duration and returns the full monthly and fixed cost stack.
7. When to Ask the Supplier
Selection is a free conversation with a professional supplier: send the drawings, the load schedule and the programme, and a crane desk returns a configured recommendation — class, jib, height, position and the chart evidence behind it. The ten minutes of arithmetic in this article is exactly what a good desk does for you; the difference is that they do it against the actual charts of the actual machines in the fleet. Bring the four inputs; leave with the right crane.
8. Frequently Asked Questions
A load chart is the crane's truth table: the manufacturer's statement of how much the crane can lift at every combination of radius (horizontal distance from the mast), jib length and hook height. Two numbers anchor every chart — the maximum capacity at minimum radius (the headline figure in brochures) and the capacity at maximum radius (the figure that actually governs most sites). Between them, capacity falls roughly linearly as radius grows, because the load's moment — weight multiplied by distance — is what the structure resists. Every legitimate lift is planned against the chart: the load's weight, its pick-up radius and its landing radius checked against the published figure, with rigging weight deducted. A crane without a legible load chart is not a crane; it is a speculation with a motor.
Four steps, in order. One: find the radius — the horizontal distance from the crane's centre to the load's position, measured across the site plan, not estimated by eye. Two: read up the chart to the column for the crane's configured jib length — capacity changes with jib configuration, so the chart used must match the crane as erected. Three: check the height — some charts show capacity variations with hook height on multi-fall reeving, and long lifts reduce effective capacity slightly. Four: subtract the rigging — slings, spreader bars and hooks weigh real kilograms, and the chart applies to the total suspended load. Example from a common Kenyan class (8-tonne flat-top, 60m jib): approximately 8 tonnes at 15m radius, roughly 4 tonnes at 40m, and about 2 tonnes at the 60m tip — illustrative figures showing the steepness of the fall. The lift is legal only if the charted capacity at the actual radius exceeds the total suspended load — with margin the site rules set, typically 10–20%.
Size the crane from four inputs, in this order. Heaviest single lift: the largest load the crane must pick — precast panel, rebar bundle, formwork table — including rigging. Maximum radius: the farthest point of the building from the crane's position, which sets the jib length and, through the load chart, the capacity class. Hook height: the tallest pour plus rigging plus clearance, which sets the mast height and the number of climbing sections. Duty cycle: how many lifts per hour, every hour — a crane classed for intermittent duty overheats on a precast erection cycle. Worked example: a mid-rise frame whose heaviest pick is 3.5 tonnes at 45 metres radius needs a charted capacity of at least 4 tonnes at 45m — which points to the 8-tonne flat-top class rather than the 6. Most projects are over-craneed on capacity and under-craneed on radius; the radius is the dimension that catches people.
They trade against each other, and the trade is the load chart's central story. Jib length is reach — how far from the mast the crane can place a load — and capacity is strength at that reach. Longer jibs do not reduce the crane's maximum capacity at short radius by much, but they cut the capacity at the tip dramatically, because the same structural moment limit must cover a longer lever arm. A crane might lift 8 tonnes at 15 metres and 2 tonnes at its 60-metre tip on the same chart. The selection consequence: choose jib length from the site geometry — the crane must reach every working point, ideally from one position — then verify that the charted tip capacity still covers the lightest-but-farthest loads. Farthest loads are rarely the heaviest, but they are the ones the brochure never mentions.
The reach-versus-capacity answer is always a curve, never a number, but the 2026 Kenyan fleet gives useful anchors. Common 8-tonne flat-tops on 60-metre jibs lift roughly 8 tonnes at 15 metres, 4–4.5 tonnes at 40 metres, and around 2 tonnes at the full 60-metre tip. Heavy 10–12 tonne classes extend the mid-range: about 5.5 tonnes at 40 metres. Jibs extend to 70–80 metres on larger machines, but tip capacities there drop to the 1–1.5 tonne band — useful for light distribution work, not for structural picks. The practical rule for developers: the heaviest load at the farthest radius is the only number that sizes the crane, and suppliers who size from the brochure maximum are selling you the wrong machine. Price the right machine once the four inputs are known — the calculator takes crane class, jib and duration.
Send the Drawings; We'll Send the Right Crane.
Trust Partners Geo-Group Ltd sizes, rents and crews tower cranes across Kenya — Potain and Liebherr fleets, certified operators, load-chart-backed recommendations and itemised quotations. Price your project or talk to the crane desk today.
Price Your Project on the Calculator✉️ Contact Us
📞 +254 718 68 69 67
How to Choose the Right Tower Crane for Your Construction Project in Kenya: Load Charts Explained
The brochure sells maximum capacity; the site demands capacity at radius. Learn to read a tower crane load chart in ten minutes — and size the crane your project actually needs.
1. The Load Chart Is the Crane
Two cranes can share a mast height, a paint job and a brochure — and differ by half their working capacity, because the load chart is the machine's real specification. Everything else is geometry and electrics. A tower crane lifts by resisting moment — the load's weight multiplied by its horizontal distance from the mast — and the load chart is the manufacturer's map of exactly how much moment the structure can resist at every radius, jib length and height. This guide teaches the ten-minute literacy that separates a correctly sized crane from an expensive disappointment, from the team behind our services — Trust Partners Geo-Group, whose crane desk sizes machines from load schedules every week.
2. Anatomy of a Load Chart
A tower crane load chart reads like a mileage table:
- The axes: radius in metres along one side — the horizontal distance from the crane's centre to the hook — against jib length or configuration along the other.
- The cells: the crane's capacity in tonnes at each combination. The top-left corner holds the headline maximum — capacity at minimum radius; the far-right column holds the tip capacity at full jib, the number that governs edge-of-site lifts.
- The fall: capacity drops roughly linearly with radius — each additional metre of reach costs capacity, because moment grows while the structure's resistance stays fixed.
- The footnotes: height-dependent values on multi-fall reeving, in-service and out-of-service wind speeds, and the deduction for rigging — the fine print where lifts are actually won or lost.
3. Reading the Numbers: Worked Examples
| Radius | 8t Flat-Top, 60m Jib (illustrative) | Typical Lift at That Radius |
|---|---|---|
| 15 m | ~8.0 t | Precast panels, steel bundles |
| 25 m | ~6.0 t | Formwork tables, rebar cages |
| 40 m | ~4.0 t | Blockwork pallets, scaffold loads |
| 50 m | ~2.8 t | Light distribution, waste skips |
| 60 m (tip) | ~2.0 t | Edge-of-site material only |
Three readings from the table. Read one: a 3.5-tonne panel at 40 metres clears the 8-tonne class comfortably — but the same panel at the 55-metre far corner does not; the jib or the crane class must change. Read two: rigging deducts real capacity — a 200kg spreader and slings turn a 2.0-tonne tip limit into a 1.8-tonne load limit. Read three: the chart applies to the crane as erected — a jib shortened for a tight site has a different chart from the brochure configuration. Our tower crane rental desk supplies the correct chart with every quotation, matched to the machine and the configuration.
4. The Four Inputs That Size the Crane
- Heaviest single lift — the maximum load, plus rigging, the crane must ever pick. Not the average: the worst hour of the programme.
- Maximum radius — the farthest working point from the crane's position across the site plan. This sets jib length, and through the chart, the capacity class.
- Hook height — tallest pour, plus rigging, plus clearance. This sets mast height and predicts the climb count.
- Duty cycle — lifts per hour, sustained. High-frequency precast or blockwork cycles demand a heavier class than the same weights at leisure pace.
💡 The worked example
A mid-rise frame: heaviest pick 3.5 tonnes (with rigging), farthest point 45 metres, hook height 42 metres, moderate duty. Chart requirement: ≥4 tonnes at 45m with margin — which lands in the 8-tonne flat-top class on a 60m jib, two climbing sections, one crane position. Every selection resolves this way: four inputs in, chart requirement out, class named.
5. Common Selection Mistakes
- Sizing from the brochure maximum — the 8-tonne headline is at 15 metres; the site lives at 40–60.
- Ignoring radius growth — a crane positioned for the first pour may be wrong for the far wing; position and jib are chosen together, from the whole plan.
- Forgetting rigging — slings, spreaders and grabs eat capacity on every single lift.
- Wrong duty assumption — a crane perfect for steel erection may overheat on a precast cycle; class the duty, not just the weight.
- Height myopia — the crane that reaches floor twelve today must climb twice before floor twenty; climbs change the chart and the programme.
6. The Selection Workflow
- List every significant load: weight, pick-up radius, landing radius.
- Mark the crane position options on the site plan; test one position against the whole building before adding machines.
- Convert each load to a chart requirement with 10–20% margin; the controlling load is the one that demands the most crane.
- Name the class and jib; check hook height and climb count; confirm the base suits the position.
- Verify duty class and wind exposure; then price the engagement — the cost estimate calculator takes crane class, jib and duration and returns the full monthly and fixed cost stack.
7. When to Ask the Supplier
Selection is a free conversation with a professional supplier: send the drawings, the load schedule and the programme, and a crane desk returns a configured recommendation — class, jib, height, position and the chart evidence behind it. The ten minutes of arithmetic in this article is exactly what a good desk does for you; the difference is that they do it against the actual charts of the actual machines in the fleet. Bring the four inputs; leave with the right crane.
8. Frequently Asked Questions
A load chart is the crane's truth table: the manufacturer's statement of how much the crane can lift at every combination of radius (horizontal distance from the mast), jib length and hook height. Two numbers anchor every chart — the maximum capacity at minimum radius (the headline figure in brochures) and the capacity at maximum radius (the figure that actually governs most sites). Between them, capacity falls roughly linearly as radius grows, because the load's moment — weight multiplied by distance — is what the structure resists. Every legitimate lift is planned against the chart: the load's weight, its pick-up radius and its landing radius checked against the published figure, with rigging weight deducted. A crane without a legible load chart is not a crane; it is a speculation with a motor.
Four steps, in order. One: find the radius — the horizontal distance from the crane's centre to the load's position, measured across the site plan, not estimated by eye. Two: read up the chart to the column for the crane's configured jib length — capacity changes with jib configuration, so the chart used must match the crane as erected. Three: check the height — some charts show capacity variations with hook height on multi-fall reeving, and long lifts reduce effective capacity slightly. Four: subtract the rigging — slings, spreader bars and hooks weigh real kilograms, and the chart applies to the total suspended load. Example from a common Kenyan class (8-tonne flat-top, 60m jib): approximately 8 tonnes at 15m radius, roughly 4 tonnes at 40m, and about 2 tonnes at the 60m tip — illustrative figures showing the steepness of the fall. The lift is legal only if the charted capacity at the actual radius exceeds the total suspended load — with margin the site rules set, typically 10–20%.
Size the crane from four inputs, in this order. Heaviest single lift: the largest load the crane must pick — precast panel, rebar bundle, formwork table — including rigging. Maximum radius: the farthest point of the building from the crane's position, which sets the jib length and, through the load chart, the capacity class. Hook height: the tallest pour plus rigging plus clearance, which sets the mast height and the number of climbing sections. Duty cycle: how many lifts per hour, every hour — a crane classed for intermittent duty overheats on a precast erection cycle. Worked example: a mid-rise frame whose heaviest pick is 3.5 tonnes at 45 metres radius needs a charted capacity of at least 4 tonnes at 45m — which points to the 8-tonne flat-top class rather than the 6. Most projects are over-craneed on capacity and under-craneed on radius; the radius is the dimension that catches people.
They trade against each other, and the trade is the load chart's central story. Jib length is reach — how far from the mast the crane can place a load — and capacity is strength at that reach. Longer jibs do not reduce the crane's maximum capacity at short radius by much, but they cut the capacity at the tip dramatically, because the same structural moment limit must cover a longer lever arm. A crane might lift 8 tonnes at 15 metres and 2 tonnes at its 60-metre tip on the same chart. The selection consequence: choose jib length from the site geometry — the crane must reach every working point, ideally from one position — then verify that the charted tip capacity still covers the lightest-but-farthest loads. Farthest loads are rarely the heaviest, but they are the ones the brochure never mentions.
The reach-versus-capacity answer is always a curve, never a number, but the 2026 Kenyan fleet gives useful anchors. Common 8-tonne flat-tops on 60-metre jibs lift roughly 8 tonnes at 15 metres, 4–4.5 tonnes at 40 metres, and around 2 tonnes at the full 60-metre tip. Heavy 10–12 tonne classes extend the mid-range: about 5.5 tonnes at 40 metres. Jibs extend to 70–80 metres on larger machines, but tip capacities there drop to the 1–1.5 tonne band — useful for light distribution work, not for structural picks. The practical rule for developers: the heaviest load at the farthest radius is the only number that sizes the crane, and suppliers who size from the brochure maximum are selling you the wrong machine. Price the right machine once the four inputs are known — the calculator takes crane class, jib and duration.
Send the Drawings; We'll Send the Right Crane.
Trust Partners Geo-Group Ltd sizes, rents and crews tower cranes across Kenya — Potain and Liebherr fleets, certified operators, load-chart-backed recommendations and itemised quotations. Price your project or talk to the crane desk today.
Price Your Project on the Calculator✉️ Contact Us
📞 +254 718 68 69 67
