3-, 4- and 6-point belts and their attachment explained simply.

It is important that you form a unit with the seat shell, which at best should not be separated.

SPEED Engineering GmbH

Even the best seats and seat consoles are useless if you slide back and forth like on a church pew when cornering or braking. Of course, this happens much less with classic racing seats than with standard seats, but in the long term you will still need proper seat belts.

It is important that you form a unit with the seat shell, which ideally should not be separated. You need arm and leg room to steer, while your body remains firmly in position in the seat. At all times.

This immediately clarifies that the standard 3-point belts, which give the upper body a lot of room to move, are 99% unsuitable for the racetrack. If you brake hard, the worst that can happen is that you slide forward before you are "caught" by the belt tensioner and fall back into the seat. The result is body tension that you consciously exert in order to defy the G-forces. The ride is like a nervous strain and you can hardly concentrate on the road.
Rigid 3-point sports harnesses can help here. These are usually bolted to the original attachment points of the standard seat belts and to a point on the rear seat and allow your upper body less play.
For advanced use on the racetrack, however, we recommend at least rigid 4-point belts. The advantage of these are the independent shoulder straps, which are brought together in the 3-point harness. This results in an even better fit for the rider and a more even load. In our store you will only find 4-point belts from Schroth. Why is that? - These belts are type-approved in accordance with ECE-R standard 16.04 and are therefore registration-free! In addition, the 75mm wide shoulder straps offer the best support and comfort at the same time. Example: A 50mm belt can be very restrictive on the shoulders of people with a broad build. The best feature, which also leads us directly to the 6-point harness, is the option of extending the Schroth 4-point harness to a 6-point harness. The buckle offers space for a double crotch strap, which also prevents you from slipping under the lap belt. This makes this harness the only 6-point harness with pressure buckle and ECE approval and perfect for use on the track if your track tool still has road approval.
Pressure buckle? - Another word... All the sports and racing harnesses presented so far, as well as the standard harness in your vehicle, naturally have a buckle. Since the pressure mechanism became established a long time ago in road-approved cars and the handling of such a mechanism in the event of an accident is generally known, only belts with pressure buckles are ECE-approved. Sports and racing harnesses that are equipped with a twist lock have FIA approval at most, can hardly be registered even via individual approval and in the rarest case bring you closer to road approval. These are of course also suitable for use purely on the track.

How do I attach the belts? - The attachment of all the belts mentioned above depends on your vehicle and any specifications of your TÜV inspector. There are various options here:

Attachment to eyelets and counter plates:

This requires straps with latching fittings that can be latched into the eyelet. The ring eyelet itself is attached to your vehicle with counter plates. In this case, it is essential to discuss with the TÜV inspector where the attachment makes sense.

Mounting on standard fastenings:

If possible, the TÜV welcomes the use of standard fastening points. This is because these are guaranteed to have sufficient load-bearing capacity when it comes to fastening seat belts.

Here you also have the choice between belts with ratchet fittings, which you can attach to the vehicle using the Schroth B23 kit, or belts that have screw-on fittings that are screwed directly to the given attachment points.
The advantage of installing belts with ratchet fittings using the B23 kit is that the B23 kit is designed to be bent into position. This means that you do not have to adjust the fittings of the belt itself compared to belts with screw fittings.

There are adapters for standard seat belts that allow you to continue using the rear seat bench in a Clubsport conversion and hook in 3- and 4-point belts if required. Of course, only if there are no people sitting in the back. A system like this was also used in the M5 Ringtaxi, for example.

Mounting on seat consoles/L-adapters:

Some of our L-adapters have suitable holes for attaching belts. We have deliberately integrated these into the L-adapter, as this eliminates the annoying adjustment of the lap belt length when adjusting the seat. Our L-adapters also have the necessary strength for this type of installation.

Important note: Many manufacturers include mounting material with their harnesses. When attaching harnesses with screw fittings, it is recommended to reuse the original screws of the attachment point instead of the mounting material. - Despite the convention that a 7/16" UNF thread should be used for restraint systems, we have repeatedly seen discrepancies between manufacturers! You should also ensure that an M12 screw is not used here by mistake. This can sometimes be screwed in several threads, but is definitely not suitable as a replacement for a suitable 7/16" UNF screw!