NASCAR sent a notice to Cup Series teams on Tuesday detailing changes to the Next Gen chassis that will see the rear crash structure change and are expected to result in safety improvements.
Drivers have expressed concerns about the intensity of impact during a collision and these changes should lessen impacts to the rear of the car. The changes will result in modifications to the center section, rear clip and rear bumper supports.
Drivers have talked about the impacts with the Next Gen car, especially since Kurt Busch and Alex Bowman have been sidelined due to concussions and concussion-like symptoms related to these types of crashes. NASCAR recognized there were problems and modeled the chassis changes with the recently tested results. These changes were presented to drivers on October 8 during a meeting at Charlotte Motor Speedway and are in the process of being initiated for the 2023 season.
The overall goal of these changes appears to be to create a better crumple zone behind the driver and allow the rear components to dissipate more energy in a collision to reduce the impact on the driver. The changes will occur in three main areas of the rear of the car, including the rear bumper struts, rear clip and rear of the center section.
The first change noted in the document is the introduction of new rear bumper struts, which are triangular brackets that hold the bumper beam to the rear clip. These spacers will be replaced with a new part that will see the thickness of the material increase to 0.080 inches to allow them to crease better. These spacers are visible above in red and blue. The bumper beam itself will be carried over from this season.
The back clip and center section will not be replaced, but will be modified and updated. These modifications will be made as these parts are sent to Technique Chassis – the single supplier that builds and services these components – for refurbishment. The costs of manufacturing, materials and labor to make these updates during the refurbishment will be covered by NASCAR and teams will only be responsible for customary finishing work such as painting.
The rear clip will see the removal of the longitudinal bars (marked in red in the illustration above) as well as a change to the bottom rails (marked in yellow). They now appear to be designed as mitered compound tubes (shown in green on the right). These bars run parallel to the racing surface and contribute to the rigidity of the entire chassis. Their removal and modification should allow this area to deform better in the event of a rear impact.
The center section features a number of changes, starting with the outer diagonal tubes at the rear (in purple above). These bars will be replaced by the same cross tubes which now feature a trigger on the inboard side. The outer diagonal tubes at the bottom (in orange above) will be replaced with 1.75 inch diameter tubes with a 0.65 inch wall as well as triggers. The interior diagonals (in green) will be reduced to 1 inch diameter tubes with a 0.065 inch wall without triggers. The intention of designing some trigger tubes is typically to improve the ability to absorb impact energy in a progressive and controlled manner through local modification of the material properties. This is intended to allow material deformation to be introduced precisely where it forces the tubular structure to deform in a high energy absorption mode and reduces the maximum load in a controlled manner.
All of these changes combined aim to introduce more wrinkle-prone and energy-absorbing elements between the rear of the car and the driver’s cabin. This should result in an increase in safety and a reduction in the force exerted on the driver during a rear impact. The introduction of this update plan for 2023 indicates that drivers were likely happy with what NASCAR showed them from the simulations run on these parts during their meeting last weekend.
It’s obvious that security is the main focus of this update, as the changes will likely result in increased costs in the future. Although NASCAR will pay for the initial updates, the parts will likely see a shorter lifespan in the future due to the reduced structure. Parts will need to be refurbished more often to bring them back to specification after small incidents. In addition to remanufacturing costs, the other concern with the changes will be how well chassis parts will remain in compliance over multiple races, as components are now more likely to bend with less support. This could cause them to no longer meet inspection requirements specifications sooner and require more frequent visits to be refurbished.
These concerns are minor compared to the possible security benefits. It also shows that NASCAR and team owners are willing to invest in a solution that can be deployed quickly to improve driver safety, even if it comes at a cost to everyone in the future.
Teams will need to dismantle all of their current cars down to the bare chassis they wish to use for the 2023 season and send them to the seller for refurbishment. This means that Technical workshops and chassis will be busy over the winter as they update hundreds of rear clips and center sections.
NASCAR did not immediately respond to our request for comment.
