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Mechanical components for the automotive sector

Defontaine, your quality partner in the automotive industry since 1946.

European manufacturer of mechanical components for the automotive industry

The Defontaine company was founded in 1946, and has ever since been providing specific expertise in the production of mechanical components for the automotive industry. We are constantly developing and adapting our industrial processes to the latest technological developments. 

Defontaine’s expertise is recognised by all car manufacturers and equipment suppliers. We supply a wide range of mechanical components for engines and transmission systems, including starter ring gears, flywheels, inertia rings, sensor rings and E-mobility components for millions of vehicles every year.

Our know-how and the renowned quality of our products allow us to export our products to the European market and all over the world.

We are investing in Research & Development to contribute to the development of new forms of mobility in line with the latest trends in the automotive industry. As a result, we have been able to improve the lifespan of our engine products to adapt to the Start & Stop technology. We are also working on future developments in the transport sector, producing parts for electric engines.

  • Defontaine equips millions of vehicles each year in Europe
  • Most valued partner for both manufacturers and equipment suppliers

Would you like to know more about our starter ring gears and flywheels?

Components for combustion and hybrid engines manufactured by Defontaine

Defontaine equips vehicles with combustion and hybrid engines components

We focus on the production of flywheels, starter ring gears, dual-mass flywheel inertia rings and sensor target rings. 

We have gained valuable experience in production over many years, supplying long-lasting parts for your car engines. Our know-how and the processes we use provide cost-saving solutions for the production of these technical parts.

couronne de démarreur rollix e-mobility

Equipping the electric vehicles of today and in the future with innovative components

un employé defontaine usine une pièce rollix e-mobility

New applications or technological constraints introduce new developments in our production modes and operating methods. Our major challenge: reducing the level of greenhouse gases in the transport sector. 

Equipping new electric vehicles with motor parts is part of this objective. Our aim is to offer car manufacturers concrete solutions for electric vehicle components with the same quality as for combustion engines. 

For example, we are making major investments in E-mobility to equip new engines and powertrains with high-performance components: planetary gears, ring gears, flywheels, inertia rings or sensor rings.

Our certifications for the automotive sector

An economic and technical approach to the design of car engine parts

Our extensive know-how and manufacturing methods allow us to provide a product that is precisely forged to comply with the required machining dimensions. This is the challenge of the flash-butt welding and rolling processes for the manufacture of rings for the automotive sector.

We also use other technical processes for the manufacture of starter ring gears, such as gear cutting to comply with your requirements or heat treatment and induction hardening.

We offer just-in-time services, ensuring that your parts are delivered on time.

volants moteurs et couronnes de démarreur defontaine

Choosing quality for your car engines

Our projects developed for the automotive sector rely on a lean manufacturing organisation. Each component manufactured in our workshops meets the current automotive standards and the specific technical requirements of our customers.

We have extensive knowledge of the automotive sector and we also believe in the importance of the origin of our raw materials, in order to offer a completely transparent service to our customers. Therefore, we are also responsible for the qualification of materials at our suppliers’ premises. 

We manufacture automotive parts, and also carry out tests for each project to ensure the safety and compliance of the vehicles.

Defontaine, expert in flywheels and rings for the automotive industry

Defontaine is a French manufacturer, designing and producing flywheels and rings, with or without gear, since 1946. We offer innovative solutions and design parts specifically made for your application. Defontaine is a most valued partner of car manufacturers, providing expert advice and guidance in the design and manufacture of your engine and powertrain components.

Working together to optimise performance.


Associated services

& design



& Services


We have set up specific services to guarantee the quality of our products and the satisfaction of our customers throughout our exchanges.

Deadline constraints, technical challenges, secure deliveries, guaranteed lifespan of parts… the services of the Defontaine Group facilitate our collaboration.

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