The classic screw-on freewheel.
The freewheel can be attached to the hub in different ways. In the conventional screw-on freewheel the freewheel is provided with internal screw thread and the external screw thread hub. The freewheel is screwed to this. The thread can have the following size:
- BSC 1.37O24 TPI
- ISO 1.375″ 24 TPI
- Italian thread 35 mm x 24 TPI
- French thread M 34,7 x 1.
A freewheel with BSC, ISO or Italian thread are not interchangeable.
The screwed freewheel being applied less and less on the hub, since it has the following disadvantages
- between the right bearing and the mounting of the axle there is a distance of about 3 cm so that the shaft is subjected to locally heavy bending stress.
- the freewheel is supported only on the hub, so that the connection between the hub and the freewheel is taxed heavily on bending. The thread must therefore have a large diameter. The hub itself is also heavily under bending stress.
- The classic the freewheel must be by the way of fixing to the hub have a large diameter. In order to mount the small chain wheels the freewheel at the ends should have a small diameter. The freewheel is therefore stepped, and the chain wheels for attachment to the hub side differences with the sprocket wheels for attachment to the end.