Racing Seats

The Rules

The rules are pretty much the same across sanctioning bodies (ARA/CARS/NASA/SCCA), an FIA homologated seat must be used. CARS is the only sanctioning body currently enforcing expiration dates on seats (5 years recommended but they allow up to 10 years from date of manufacture).

Seat sliders are pretty much banned across the board even though FIA allows them (if they are FIA homologated which pretty much none of the available sliders on the market are).

ARA rules are below but the FIA Article 253 rules have much more details about installation instructions.

Safety guideline

Here are the FIA seat guidelines and some additional safety aspects highlighted during the FIA Safety Week seminar on safety equipment that also discusses racing/window nets:

Headrest padding

The most advanced guidelines for seat foam and headrest padding are in the Cross Country seats foam guidelines from the FIA (link to the document below).

If you want to upgrade your padding in your seat, FIA technical list 17 contains the list of approved padding. In the US., BSCI Inc and Fiberworks LLC (both in Mooresville, NC) provides Ener-Core EC50 (orange) as the only FIA approved padding.

For the categories specified in Appendix J, Article 283 only: to accommodate the installation of add-on padding, competitors are permitted to remove the seat’s original foam, provided this is done exclusively in the area surrounding the head. Some additional rules:

• All foam and padding within the seat must be covered by flameproof cladding.

• Removable padding must be securely fixed to ensure that it remains attached under racing conditions.

• All foam and padding must remain within the seat profile.

Seat inserts

Racing seat foam insert rules require adherence to specific material safety, fire-retardant coverage, and structural support standards depending on the sanctioning body. They can be very helpful especially with smaller competitors that may not properly fit in standard seat sizes.

• SFI 45.2 Specifications: Many major racing organizations require custom-poured foam inserts to meet SFI 45.2 standards, which mandate energy-absorbing properties and self-extinguishing fire behavior. Kits like those from BSCI utilize approved materials like EIS W50 or ENER-CORE EC 50.

• FIA Guidelines: For FIA-homologated events, any foam insert used between the driver and the homologated seat must maintain minimum lateral support dimensions (such as 230 mm at the head, 180 mm at the shoulders, and 100 mm at the pelvis), and secondary non-homologated cushions are restricted in thickness (maximum 50 mm). 

• General Fire Safety Rules: Standard hardware-store polyurethane or expanding foam is strictly discouraged or banned by strict rulebooks because it can melt and create a hazardous, flammable residue during a fire. Raw foam must typically be wrapped or covered with a fire-retardant fabric layer like Carbon X or Nomex. 

Here is a video showing how to pour the foam for a custom insert in an aluminum racing seat:

Installation

Seat support

The seat must be secured to the car by at least 4 mounting points. It can be bolted directly to the chassis (see below left) or another popular option is to use a seat mount that re-uses the factory mounting points (picture below right). The depicted Planted seat brackets are a low cost popular option: https://www.plantedtechnology.com/products/seat-brackets.html

An alternative is to have new crossmembers to support the seats. They must be secured to the chassis using end plates. The pictures below show example of seat support crossmembers. Note that the bar can be a square or round tube but it has to be secured to the chassis and cannot be welded to the cage by FIA standards (it should also be straight and not be bent).

The FIA specifications for new seat mount bars can be found in Appendix J Article 253 with diagram 253-65B detailing the specs of the different components:

Be very careful if you use mounting tabs, here is the warning issued by MSUK:

'There are concerns over the quality of some ‘transverse rail with tab’ type mounting, and failure of such mountings, where the seat is held in position by only the overlap of a nut in a slotted tab, have been seen. Example of the type of failures can be seen in the images below, where the nut has torn through the slotted tab in an accident. This is of particular relevance in the case of rearward impact, where the harness offers less support to the occupants and the weight of the occupant’s body acts as a levering force on the seat backrest. Pulling up on the seat mounts. '

Link to full MSUK document: https://www.motorsportuk.org/wp-content/uploads/2020/09/Seat-Installation-Guidance-v4.pdf

Seat angle

Remember that the seat angle must match the angle of your Hans model. If you have a Hans model 20, the seat back rest should be at a 20 degree angle with the vertical (see diagram below).

The seat should also be installed in front of the main rollbar, there is a minimum distance of 90mm between the rollbar and the inside of the seat backrest.

Some general guidelines to adjust a seat:

1.  Find the height you want first to have a good visibility through the windshield, you don't want to be too low so that you can't see above the dash especially over a crest and you don't want to be too high where your helmet hits the cage. 

2. Adjust the front/rear position so that your legs are at the correct distance to operate the pedals comfortably. 

3. Finally you can fine tune the angle to get your arms in a comfortable position, keeping in mind that the backrest should be at an angle that matches your Hans device.