The weekend practice at Darlington Raceway will see a new rule: teams in the NASCAR O’Reilly Auto Parts Series can now swap rear springs.
Revolutionizing Session Adjustments
Until now, practice changes have mirrored those a pit crew can make on the track—tire pressure tweaks, trackbar or shock rail adjustments, and other minor modifications. After the pandemic trimmed session lengths to 50 minutes, NASCAR tightened the list of permissible changes, limiting teams to only small, incremental tweaks at the rear of the car.
Why Rear Springs Matter
Rear spring replacements directly influence how a car turns, especially on a challenging oval like Darlington. With a fresh set of tires, teams can unscrew and retune a sprung lower end rather than settle for the combination tested weeks earlier in the simulator. The flexibility gives smaller outfits a chance to catch up, affirming that even modest parts changes can shift a field.
What NASCAR Allows Now
Besides the newly added rear spring exchange, the practice window remains a rough replica of a pit stop. NASCAR still permits only tire pressure adjustments and small spring rate modifications made with the adjustment wrench in the car. Although the Cup Series has experimented with an additional tire set at New Hampshire Motor Speedway, the set of allowable adjustments has stayed the same.
Industry Response
Garage crews and team leaders welcomed the rule as it “provides teams with more instant solutions and gives us a smooth path to use parts we already own.” Officials said the change reduces the need to rely on simulation prep and encourages more real‑world testing during practice. Todd Gordon, crew chief and rider on “NASCAR Inside the Race,” highlighted that broader spring options could open future possibilities for the Cup and Truck Series.
In allowing rear spring swapping this weekend, NASCAR takes the first step toward expanding practice flexibility across the sport.
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