The standard is a pair of six-spoked 22" diameter cast flywheels. balance weights are cast integrally with the rims and drilled for final balance.

A single spoked or solid flywheel appears on sets for pumping and lighting (and no doubt other purposes). Solid flywheels exist with three small round holes or three larger oval holes. The reason for the difference is not known but dealing with casting stresses is one possible explanation.

A pair of solid flywheels has been seen but the original purpose of that engine (c1924) is unknown.

The flywheels of the cistern hopper (Benford) model are unique and incorporate stud bosses halfway along three spokes for fixing the governer cover. That model used a normal starting handle and a pure governer cover was used in place of the usual combined governer cover and starting collar.