1. Introduction & aim of the conversion 🚗

Presentation of the project: 

The rear axle of the BMW E90 (e.g. 330i or 325i) is fitted with the 336x22mm brake disc (OE number: 34216855004) as standard.

The aim was a significant upgrade to modern 370×24 mm brake discs from the BMW M2 (F80) (OE number 34212284812), combined with a Maserati Granturismo M145 4-piston calliper (OE number 82102701 and 82102801).

Why this Setup? 

We chose this combination because the adaptation with the 370x24mm brake disc from the BMW M2 (F80) in conjunction with the matching 4-piston brake calliper from the F2x F3x series (34216799462 ) is not technically feasible.

To be able to drive this combination, threads must be drilled into the steering knuckle and the brake calliper must be converted with the aid of bushes. In the case of conversions where the steering knuckle has to be machined, the TÜV does not play along under any circumstances and is absolutely not recommended by us. For these reasons, we offer the solution with the Maserati brake calliper.

The challenges: Larger diameters require suitable adapters, spacers and mounting points for the more solid 4-piston caliper.

2. Technical details of the upgrade

• Brake disc 370×24 mm OE 34212284812 from BMW M2 F80 – Replaces the standard 34216855004. Provides 53 % more surface area and increases thermal performance.

• Caliper Maserati M145, 4 piston with OE‑numbers 82102701 (left) and 82102801 (right). Hard braking power due to larger piston surface.

• Epytec-Brake caliper adapter: Specially manufactured for bolted connection on E90 rear axle. Adapters accept Maserati calipers and are bolt-on with original axle mount.

• Hardware & Distanz: High-strength bolts, adapted to centre distance E90.

• Adjustments: Precisely manufactured by us in-house. No modifications to wheel hubs. Plug-and-play as required.

3. Implementation variant for the customer: Customised production completely at Epytec - prototyping based on components sent to us

Our customer Adrian opted for the complete service from Epytec. He provided us with all the relevant components - including the original Maserati Granturismo M145 brake callipers with the OE numbers 82102701 (left) and 82102801 (right), as well as the desired 370x24 mm brake disc with the OE number 34212284812. We also had the original wheel bearing housing from the BMW E90 (OE number 33326783668) for precise measurement.

Procedure at our premises:

After receipt of the goods, the components were systematically recorded and analysed metrologically in our workshop. Our technicians carried out a complete geometry survey to define the exact fit of the brake caliper to the brake disc and ensure correct positioning on the rear axle. We paid particular attention to piston centring, disc depth and clearance to the wheel mount - always with a view to plug-and-play installation without further adjustments.

Based on this data, we developed a customised Epytec brake calliper adapter that is precisely matched to the standard mount of the BMW E90. The adapter enables the Maserati calipers to be bolted on directly and ensures an exact fit to the 370x24 mm brake disc - without any modifications to the vehicle itself.

After successful prototyping, we manufactured the final version of the adapter from high-strength aluminium with tested material quality - naturally including a material certificate for submission to the TÜV or inspection body. Thanks to our in-house production in Germany, we were able to ensure rapid realisation and maximum precision.

This variant is perfect for customers like Adrian who already have suitable components and need a customised solution - with complete development work by us.

4. TÜV & Authorisation

For the conversion to the 370x24 mm brake disc (OE number 34212284812) in conjunction with the Maserati M145 4-piston brake callipers (OE numbers 82102701 and 82102801), we supply all the necessary documents to enable registration with the TÜV without any problems.

You will receive the following documents as standard with your Epytec tuning adapter:

• ✅ Material certificate in accordance with test requirements for submission to technical testing organisations
  📄 View sample material certificate here

• ✅ TÜV certification for the manufacture of tuning parts– Proof of our certified manufacturing expertise according to current standards
  📄 show certification 

• ✅ Optional: FEM-calculation– On request, we can prepare a stress analysis for structural verification in accordance with §21 StVZO
  📄 View sample FEM analysis

For registration, we expressly recommend working with one of our TÜV partners from our Germany-wide network of inspectors.
🔧Find a suitable TÜV inspector here

This means you are ideally prepared for legally compliant and uncomplicated registration of your upgrade.

About Epytec

Epytec is a leading specialist in the manufacture of tuning adapters, with more than 15 years of experience in the industry. Our products, which are manufactured entirely in Germany, stand for quality and innovation. Tuning adapters are essential connectors between car parts that make it possible to combine components from different vehicles. Our adapters make it possible, for example, to adapt a high-performance Porsche brake to a Golf GTI or to install a powerful Audi engine in a VW Transporter. This flexibility enables individual adaptations and optimisations that would otherwise not be possible.

Our commitment to the highest quality standards and the satisfaction of our customers is also reflected in our service. We guarantee trouble-free registration with the TÜV, which gives our customers security and confidence in the legality of their conversions. This combination of first-class products and excellent customer service has made Epytec a market leader that inspires hobby tuners as well as professional mechanics and vehicle builders. With Epytec, you are opting for proven technology "Made in Germany" that not only makes your vehicle more powerful, but also more individual.

We can also help you with your customised solution

You can quickly and easily configure your own customised product here