How to size a roller conveyor the right way
A roller conveyor moves cartons, totes and pallets smoothly through picking and dispatch. This guide shows how to set roller pitch, axle load and slope, and when a gravity or powered line with curve modules is the right choice.
View roller conveyorsGravity or powered roller conveyor - which fits?
A gravity roller conveyor uses a gentle slope so the load rolls by itself - cheap, low-maintenance and ideal for short runs and buffers. A powered roller conveyor with driven rollers or a chain drive moves the load actively and suits level runs, inclines, timed processes and heavy goods.
The choice depends on weight, distance, height difference and cycle time. Flow racks and simple transfers usually run on gravity; as soon as you need a defined speed, accumulation or horizontal transport, a driven line becomes essential.
- Gravity conveyor: no power, 2‑4 % slope, for cartons and totes with a smooth, firm base.
- Powered conveyor: 24 V driven roller or chain, constant speed, accumulation-capable and incline-ready.
- Skate wheel rail as a light variant for very low loads and flexible layouts.
Plan flow racks, totes and conveyor paths as one coherent system.
Read the guideHow do you set roller pitch and axle load?
Core rule for roller pitch: at least three rollers must always sit under the shortest load. The pitch equals the smallest container length divided by three - a 240 mm short tote allows about 80 mm pitch at most.
The axle load is how much weight a single roller may carry. You pick the roller tube (steel, galvanised or plastic) and diameter by load weight: light 20‑50 mm steel rollers for cartons, sturdy 50‑80 mm tubes for heavy totes, and heavy-duty rollers up to about 300 kg each for pallets.
- Conveyor width = load width plus 50 to 100 mm clearance for safe guidance.
- Galvanised steel tube for durability, plastic for quiet, corrosion-free areas.
- Ball-bearing rollers for easy running and low rolling resistance.
What slope and which curve modules do you need?
On a gravity conveyor the slope decides safe running. Typical values are 2 to 4 %, meaning 2 to 4 cm of drop per metre. Light cartons need more slope than heavy totes because rolling resistance matters relatively more.
Too much slope lets the load accelerate and pile up at the end; too little makes it stall. For direction changes you use curve modules: 30, 45 or 90 degree bends with tapered or differential rollers that keep the load on track because the outer lane runs faster than the inner one.
- Plan an end stop or brake roller to prevent run-on at the line end.
- Choose curve modules with a matching inner radius so long goods do not jam.
- Align transfer points flush and keep height steps below 3 mm.
Frequently asked questions
How many rollers must sit under the load?
Always at least three rollers carry the shortest load at once. That sets the maximum roller pitch: the shortest load length divided by three.
What slope does a gravity roller conveyor need?
Typically 2 to 4 %, meaning 2 to 4 cm per metre. Light cartons prefer 3 to 4 %, while heavy totes run safely at 2 to 3 %.
When is a powered roller conveyor worth it?
As soon as you need level runs, inclines, constant speed, accumulation or timed processes. Short buffers with a slope usually run on the cheaper gravity line.
How do curve modules work?
Tapered or differential rollers compensate for the outer lane travelling farther than the inner one. This keeps the load on track through the 90 degree curve without skewing.
Roller conveyor planned around your flow?
We supply gravity and powered roller conveyors, curve modules and accessories - matched to roller pitch, axle load and your route.
Correctly sized
Axle load and roller pitch calculated for your goods.
Safe running
Slope and brake rollers for controlled transport.
Modular and scalable
Straights, curves and transfers combine freely.
Expert advice
Our specialists help plan your conveyor route.