CNC Machining
BMW E34 Flywheel Ring Gear — CAD Design and CNC Machining
Flywheel ring gear for BMW 5 Series (E34) designed in CAD from original measurements. CNC machined with induction-hardened teeth.
Technical Specifications
- Material
- C45 steel (1.0503)
- Tooth module
- m = 2.5
- Number of teeth
- 130
- Pitch diameter
- Ø325 mm
- Hardening
- Induction 55 HRC / 1.5 mm depth
- Design
- 3D CAD — involute teeth
- Vehicle
- BMW E34 (5 Series)
- Installation
- Heat-shrink fit (interference)
Challenge
The owner of a classic BMW E34 needed a new flywheel ring gear — the original part was no longer available as a spare. The ring gear had to ensure proper engagement with the starter motor and withstand repeated engine start cycles.
TMT Solution
Based on measurements from the removed ring gear, we designed a 3D CAD model with complete involute tooth geometry. The part was cut from a C45 steel ring on a CNC machining center. Teeth underwent induction hardening to 55 HRC at 1.5 mm depth, maintaining a ductile core.
Result
The ring gear was installed on the flywheel using the heat-shrink method. After installation, the engine started correctly — starter engagement was smooth and noise-free. The client confirmed full compatibility with the original Bosch starter motor.
Related service: CNC Machining →
Frequently Asked Questions
Do you manufacture custom flywheel ring gears?
What hardening method do you use for ring gear teeth?
Can you design a part from measurements of the original?
Need a similar part?
Send us a technical drawing or description — we'll quote within 24 hours.
Send inquiry