What matters in today’s NASCAR Cup Series race and what method for obtaining track position is rewarded most? Let’s dive into the analytics and trends and that will shape the Buschy McBusch Race 400 at Kansas Speedway (3 p.m. ET on FS1):
Track position at Kansas will come the hard way
Both unforgiving and random, Kansas Speedway has an identity crisis.
What four races in the 550-horsepower, high-downforce era have taught us is that track position on the 1.5-mile oval is a form of wealth with a massive divide. Those who have it or can regularly get it are rewarded handsomely. Those who lack it or lose it are crushed, stymied by a track where meaningful passes were hard to come by before 2019’s shift towards reduced horsepower.
Within the races in that span, three winners boasted elite surplus passing values, the difference in a driver’s adjusted pass efficiency and the expected pass efficiency of a driver with the same average running position, based on a field-wide slope:
Brad Keselowski and Denny Hamlin conquered Kansas thanks to an ability to conjure track position at an efficient clip relative to the rest of the field. Though not a novelty, sky-high surplus passing values for race winners occurred more frequently at Kansas than on other similar intermediate tracks across this era:
The outlier among the last four Kansas events was the 2020 playoff race in which Joey Logano fended off a faster Kevin Harvick on a 42-lap green-flag run to the finish.
While the storyline surrounding the outcome centered on Harvick’s inability to pop the pocket of air cleanly enough to complete a pass on Logano — further evidence Kansas rewards drivers who can routinely pass without struggle — the go-ahead lead was clinched on pit road when Harvick’s typically pristine crew, ranked first in four-tire median box time in 2020 according to Motorsports Analytics, offered a rare slow stop on a day when Logano’s crew earned him a race-best 16 spots under caution-flag conditions, track position acquired in lieu of traditional passing.
For Harvick, the minor foibles added up to a loss, cementing the fickle relationship between speed and results at Kansas.
While a track like Atlanta represents an idyllic scenario — speed ranking very nearly holds a perfect correlation with finishing position — Kansas fell on the other end last season, at times offering more random results than expected from a NASCAR race. Last year’s summer tilt, won by Hamlin, saw a correlation coefficient of +0.6, while the playoff race in the fall improved to +0.8.
Restarts will be cramped, panicked and, ultimately, rewarding
A key window for positional change, restarts, provide close-proximity pack racing reminiscent of Daytona or Talladega.
The best restart spot with a positive net gain over the last four races was sixth place (the outside of the third row), from which occupants averaged a 5.91-place running position after two laps. That we have to search past the first two rows for a positive average gain is a telltale sign that no front-running position is truly safe on Kansas restarts.
In this sense, mitigating likely losses will be key. The choose rule allows for drivers to avoid the non-preferred groove — the inside line at Kansas — but those able to retain position when in a disadvantaged spot will live to fight for positions deeper into the green-flag run.
A good example of how to calmly mitigate track position loss on a chaotic Kansas restart was demonstrated last season by Martin Truex Jr.
On the final restart in the July race, Truex (in the blue No. 19) was tasked with protecting the seventh-place position, a spot containing a 30 percent chance of retention. He turned in a one-position gain which acted as an unlikely springboard into clean air for three more spots and a third-place finish following the final intermediate run:
A lesser restarter would’ve panicked when Aric Almirola’s line drifted too close; Truex’s deliberate inaction — less is more on restarts with the 550-horsepower package — helped steady the lap and yield the gain. He also timed the use of Kansas’s speedy apron to his advantage. There wasn’t much else Truex could’ve successfully done here, and that’s precisely the point. Bad restarters would try to do more in this scenario.
Truex (-0.74) is currently one of eight drivers averaging a net loss better than 0.75 positions per non-preferred groove restart on choose-rule tracks. The others are Chase Elliott (+0.12), Keselowski (-0.08), Ryan Blaney (-0.24), Hamlin (-0.32), Kyle Larson (-0.59), Logano (-0.67) and William Byron (-0.73).
Larson a winless standout at Kansas
— Positive Regression (@PosRegPod) May 1, 2021
Among the eight drivers who mitigate restart loss the best, three of them stand out for the speed of the cars on 550-horsepower tracks.
Larson, Keselowski and Byron rank first, second and third, respectively, in average median lap rank, an average of a team’s median lap rank for each race measured by Motorsports Analytics. Of those three, Larson won the only other race this season (Las Vegas) utilizing the tire combination we’ll see this afternoon.
Despite being winless in 12 career Kansas starts, his efforts in scoring track position on this track in the 550-horsepower era stand out. In the 2019 spring race, his +4.33% surplus passing value netted 19 positions beyond his statistical expectation and rivaled the corresponding numbers for eventual winner Keselowski. He finished eighth in the 11th-fastest car. Later that fall, he turned in a 14th-place finish but ended the day with his pass differential in the black, a +2.96% SPV, good for 10 positions beyond his expected net.