MDR Motorized Drive Roller Selection Chart — Torque, Belt Pull, RPM

Motorized drive rollers and hub motors are rated by tube length, so the torque and belt pull a series delivers depend on the width of your conveyor. This chart interpolates each OneMotion series between its minimum and maximum length at the roller length you enter, shows whether the series physically fits, and lists continuous torque, peak torque, belt pull, and speed range side by side.

Worked example: a 24 in roller carrying 60 lbf of belt pull at 100 ft/min on a 1.9 in diameter roller needs 60 × 0.95 = 57 lb·in, about 6.4 N·m, at the roller; with the 1.5× thermal safety factor the series must offer 9.7 N·m continuous, and it has to turn 100 × 12 / (π × 1.9) = 201 rpm within its speed range. Type the torque your application needs and the chart recommends the smallest series that meets it, flags near misses, and shows the alternatives.

Belt pull for the required torque comes from the belt pull calculator, which can hand its result straight to this selection; the Torque & Motor card does the same for shaft-driven belts.

How it works
  • Specs interpolate linearly between the series' minimum and maximum tube length; outside that range the motor does not fit.
  • Required torque = belt pull × roller pitch radius; the recommendation applies a 1.5× thermal safety factor to continuous torque.
  • RPM = belt speed × 12 / (π × sprocket diameter) is checked against the series' minimum and 60 Hz RPM.

Free, no login. Your inputs are saved in this browser. Values are engineering references — verify against manufacturer data and applicable codes before a final design.

Built by the engineers behind MDR sanitary conveyors.

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Questions engineers ask

How much torque does an MDR hub motor need?
Required torque equals belt pull times the roller pitch radius. The selection applies a 1.5 times thermal safety factor to the continuous torque rating so the motor runs at the duty with margin rather than at its limit.
How is the hub motor RPM checked?
RPM = belt speed × 12 / (π × sprocket or roller diameter). The result has to fall between the series' minimum RPM and its 60 Hz maximum; outside that band the motor is not offered.
Will the hub motor fit my roller length?
Each series lists a minimum and maximum tube length, and the specs interpolate between them. A roller outside that range does not fit the series, and the tool says so.

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