While Friday's 50-minute practice session at the San Diego Naval Air Station North Beach circuit for the NASCAR Cup Series wasn't as chaotic as the Craftsman Truck Series, it left drivers with one key point: tires wear out much faster than expected on the 3.4-mile street circuit.
Six to eight rounds is enough.
Denny Hamlin said he only managed to complete eight laps in the first round: “I did eight laps and the tires were at their limit at that point.” Daniel Suarez reported a similar experience: “I did six or seven laps and my rear tires were completely worn out. It’ll be fun to see.” According to Suarez, the first lap and a half is truly clean, after which the battle begins; this will make the green flag section, which could last 20 laps with the same team, extremely challenging.
When asked about the likelihood of tire punctures during long green flag runs, Hamlin responded: “I don’t expect a puncture due to running out of air. You’ll realize you’re out of tire, you’ll lose control, and you’ll have no choice but to pit.”
The marbles are narrowing the width of the track.
The second major takeaway from practice was the rapid accumulation of tire marbles in the most abrasive sections; the track consists of at least five different types of asphalt/concrete surfaces. Carson Hocevar noted that this pattern has almost become a guide: “Because the tires wear so much, the marbles are reminiscent of Formula 1. The edge of the narrow line that everyone passes is overflowing with marbles; you can almost see the ideal track like a copy of a sheet of paper.’ However, Hocevar is hesitant about how the race will be affected by the marble accumulations: ”I’m not used to so many marbles. I’m afraid of losing grip completely and sliding in the next corner while trying to overtake one.“
Ryan Blaney also described how his overtaking attempts during practice were thwarted by the marbles: “There were a lot of marbles and dust on the concrete sections from turn 10 to turn 16. I went off the line trying to overtake one and experienced the kind of slide you see on street circuits in IndyCar races.” Hamlin described the situation as 'tough': the back of the track looked quite narrow due to the marbles during practice; however, he added that he hoped the track would widen somewhat in the race, as cars would have to move out of line during restarts.
Kevin Larson led the practice on Friday. One of the notable incidents was Kevin Magnussen leaning into the wall at turn 16, while Brad Keselowski narrowly avoided a major collision by braking suddenly at turn 2. Magnussen, who has F1 experience, is competing in his first Cup race in San Diego wearing the Project 91 jersey.
Van Gisbergen is in the favorite position.
Shane Van Gisbergen, who has won two of the three Cup Series races held at Chicago Street Circuit, is naturally among the favourites ahead of Sunday's race. The three-time Supercars champion from New Zealand has a seven-time podium finish in the Cup Series and his experience on street circuits gives him a clear advantage over his rivals.