Crane gearbox selector
Enter your motor and the ratio you need. The selector checks the 2027 nominal rating charts and returns the smallest model that carries your power at the chosen service factor.
Input torque = kW × 9550 ÷ rpm · Rated = input × i × 0.98 · Max = rated × SFRatings from the J.S. Gear 2027 catalogue, interpolated for motor speed. This is a first selection only. Confirm the final model and certified GA drawing with our engineers.
Get a price for this selection
Your selection is attached to this enquiry automatically. Add your details and we reply with price, delivery and a certified GA drawing.
Change the values in the selector above and this summary updates.
How the selector works
Rounds to a nominal ratio
Your ratio is matched to the nearest catalogue ratio, from 6:1 (LT) to 560:1 (HD).
Corrects for motor speed
Catalogue ratings at 1500, 1000 and 750 rpm are interpolated to 1440, 960 or 720 rpm.
Picks the smallest size
The first model whose rating is at least
motor kW × SF, across all LT, HC and HD sizes.Shows the torque
Input = kW × 9550 ÷ rpm,Rated = input × i × 0.98,Max = rated × SF.
Before you order
The selector gives a first selection from the 2027 nominal rating charts. Our engineers confirm the final model, the actual ratio of that size and the overhung load on the output shaft, and send a certified GA drawing with the quotation.
Not sure about the service factor? Send the crane capacity and duty class in the form above and we set it for you.
Need a price or a certified GA drawing?
Send us your motor power, speed and ratio.