Can I Use Standard Seat Belts With Bucket Seats?

Browsing a track day enthusiast forum, we found an interesting question. Can I use standard seat belts with my bucket seat? Well, that got us thinking on how this works relating to an MOT and general safety of the driver. We spoke to various manufacturers and MOT specialists in order to give you the definitive answer.

Will My Car Pass Its MOT With Bucket Seats & Seat Belts?

The MOT tests and checks each component individually from each other. The MOT tester will ensure that the seat is securely fastened to the vehicle and that there is no movement with the mountings. They will then also check that the seat belt is in acceptable condition with no damage to the webbing. As long as these criteria are met, they will pass the vehicle from an MOT point of view. This also works with road legal harnesses which have the standard belt buckle clip on the lap belt.

How Can I Fit Standard Seat Belts With Bucket Seats?

The installation of the bucket seats and the standard seat belt clips will depend on the vehicle model, the mounting brackets that you’re using to install the seats, as well as the type and design of seat that you have. With so many variables, here are the most common installations that we see.

Side Mounted Bucket Seats With M2 Rails

When installing a side mounted bucket seat with a specialist M2 rail, the M2 rail has a bolt location point on the side which allows you to fit your seat belt clip. You can install your side mounted seat and seat belt clip easily on this frame.

Side Mounted Bucket Seats With Base Mounted Adapted Rails

When installing a side mounted bucket seat with an adapted base mount kit, for example, an OMP base mount bracket with some sliding rails and side mounts, you will not technically get a bolt location point for your seat belt clip. You could modify the OMP frame to accept the clip or order a separate L-bracket that we provide, which fits between the side mounts and the sliders. For more information about that product, please contact us & we’ll be glad to assist.

Base Mounted Bucket Seats With Vehicle Specific Fitting Frames

If you’re using a base mounted bucket seat like a Sparco Sprint, then we’d usually recommend a vehicle specific frame, for example, a Renault Clio MK2 frame and slider. This frame will come with a seat belt clip to allow installation of the seat easily with a standard seat belt.

Is It Safe To Use a Bucket Seat With a Standard Seat Belt?

Once you’ve installed your new bucket using your original seat belt, it’s time to check where the seat belt is positioned in conjunction with your shoulders and waist. It’s important that you know if it’s catching on the seat and if the belt is doing the job it was designed for.

If the seat belt isn’t correctly positioned with the seat and your body, it won’t provide optimum support during an incident.

There are two key areas which need to be checked. These are how the seat belt reacts with the shoulder points of the seat & how the seat belt reacts with the thigh supports. We’ll look at the two main options for configuration at both locations of the seat.

Running The Seat Belt Over The Shoulder Support (Shoulder Position One)

We would recommend that a friend takes a photo of your face when you’re sat in the seat so you can use this as a reference. The seat belt should be running from the mounting point of the car (usually the B-pillar) across your shoulder and down your body to the seat belt clip. If the natural line of the seat belt is broken by any wings the seat may have, then the position of the seat belt is not correct. Your height and body shape will affect this greatly, so the same seat will react uniquely for different drivers. We recommend that the seat belt has a natural line over your shoulder.

Using The Harness Slots of The Bucket Seat (Shoulder Position Two)

This will again be a case by case decision depending on the size and shape of the seat, as well as the location of the harness slots in line with the seat belt fixing on the B-pillar. If you can feed the seat belt through the harness slot allowing the seat belt to rest on your shoulder comfortably, then this will be suitable. This provides a better line from the fixing point that the previous method,

Running The Lap Belt Over The Thigh Supports (Lap Position One)

When you’re sat in the seat, do you have to reach over the thigh support to plug the seat belt in? Does the seat belt rest comfortably over your waist without breaking the natural line of the belt to the seat belt clip? These are two critical questions and will again depend on your size, shape and build. It will also depend on how aggressive the side supports of the seat are. Some seats only have low side supports and will allow the seat belt clip to sit correctly at the correct height, whereas other seats are rather deep, changing how well the seat belt will fit.

Running The Lap Belt Through The Thigh Support Harness Slot (Lap Position Two)

If you run your seat belt through the side harness slot and clip into the seat belt clip, again, the key is down to the natural flow of the seat belt and that, when clipped into position, it’s not pressing against any part of the seat with excessive pressure. This method can be preferred in most cases.

A Natural Flow For The Seat Belt Webbing is Key!

The main key point is that the seat belt webbing should have a natural flow and not be hindered or obstructed by the seat itself. Once sat in the seat, you will be able to see if the angle heavily changes or if it has a consistent line as the seat belt runs over the seat or through the harness slots.

We have to stress that the optimum position of this will alter for each driver using the same setup. If two drivers are different heights and figures, it could change the dynamics, as such, this is also worth checking once you have finished installation.

If you have any further questions and want to check your installation, feel free to contact us as we’ll be more than happy to help. If you have any photos, send them through & we should be able to provide you with professional advice.