Engines with planetary gearbox manual transmitting usually have a heavy flywheel, typically 5 to 40 kg of cast iron, with the starter ring gear shrunk onto the exterior.
That is done by heating the ring to around 200 °C to expand the ring which is then rapidly placed onto the flywheel, often held in firmly against a location shoulder until coolin in calm air . The interference fit between ring equipment inside dia. and flywheel, usually ranging from 0.20mm to 0.50mm, renders the starter ring firmly mounted on the flywheel.

1. Heating must be done as uniform as possible rather than with a gas burner, as this process causes great temperature variations to the pieces.

2. the temperature ought to be 200°C. A temperature greater than 350°C will affect the apparatus tooth hardness.

3. Do not make use of compressed air flow or coolant to cool down the ring.

4. A precise centering and flattening of the pieces in the flywheel is an absolutely essential condition.

5. The initial center distance should be maintained.

6. Cool power press system should be avoided because of to a substantial stress caused to the hardened region.

Engines with automatic transmissions instead possess a pressed metal plate with the starter ring equipment usually welded onto the exterior of the plate.