After Pato O’Ward’s poor qualifying effort which had him starting 25th at Mid-Ohio, the broadcasters in the NBC booth stressed that he had to “do something different”.
And sure enough, the McLaren driver’s pit wall opted for a 3-stopper instead of the favored and eventual race-winning 2-stop strategy.
Despite these setbacks, O’Ward still finished with the 3rd fastest total time in the field, covering 80 laps just 14 seconds slower than race winner Alex Palou despite finishing 28.5s behind on the track.
Of course, qualifying better could have eaten into that chunk of time a bit, but could one-less pitstop and the 30 seconds saved have made up for his poor qualifying and seen O’Ward actually come from 25th to win?
To analyze this, we need to consider two things:
- How much time would O’Ward have saved by pitting one less time? (This is the easy question to answer because it’s just the pit delta).
- How much time did O’Ward gain from having fresh tires on his extra stint, or how much time would he have lost being on older tires for longer?
The net of these two things ends up being the delta between a 2-stopper and a 3-stopper.
The second question is harder to answer because we don’t know how his tires would have held up, what traffic he would have hit, and all the other unknowns that may have occurred had he 2-stopped.
The best we can do is see how the drivers around him were affected and extrapolate out to O’Ward’s race.
Pit Delta
The pit delta for O’Ward specifically can be found by looking at his pit-in and pit-out laps, and then comparing that to his normal non-pit green flag laps.
The Pit Delta also changes as the race progresses, and particularly the 3rd stop delta was quicker for O’Ward because he needed less fuel, so we will use that delta instead of the overall average. His 3rd stop was 2s quicker than his 2nd stop and 6.5s quicker than his first.
So his 3rd stop added 26.775 seconds to his race time vs. staying out and doing average-paced laps.
Green Flag Pace
O’Ward’s green flag non-pit lap times on average were 69.8 seconds. The drivers on the 2-stop strategy were averaging 70.6 seconds per lap, but we care more about the fastest of the 2-stoppers, Alex Palou and Scott Dixon.
They were both averaging 69.95. So on a typical green-flag non-pit lap, of which there were 69 for O’Ward, he was only 0.15s faster than Palou. So that equates to about 10.4s gained over those green flag laps on pace alone.
So he gained 10.4s by choosing a 3-stop over a 2-stop, but lost 26.8s in pit-road time, for a net loss of 16.2s with a 3-stop strategy. This tells us that O’Ward likely should have stuck with a 2-stop strategy.
Compared to the field, the 3-stopper made sense as he was almost a full second quicker per lap than the average 2-stopper, meaning he made up 55s on the field to counteract his 27s stop. But the fastest 2-stoppers were able to keep a similar pace to him even on longer stints.
Navigating Traffic
What likely hurt O’Ward was all the extra passes he had to make thanks to that extra stop. O’Ward started in 25th, so he had a bigger gap to make up and 24 cars to get by. He was already 6.6s behind Palou at the end of the first full green flag lap.
O’Ward had to overtake 43 cars for position in the race, 14 more than the next-closest driver. Palou and Dixon were among the lowest in the field, with just 10 and 13 overtakes, respectively. This number doesn’t cover the backmarkers, although all drivers would have to deal with them eventually.
You can see this take effect in the data too. While O’Ward had the fastest green-flag pace of anyone, he also had one of the highest standard deviations in lap time, meaning he was not able to be consistent. The difference may seem slight, but it is enough to make an impact on your race, and this accounts for the significant amount of extra time he spent behind and navigating around his competitors.
Tire Difference
The last thing we’ll look at is the tire dropoff, which undoubtedly helped O’Ward to pump out laps almost a whole second faster than the field average throughout the race.
As you can see, there’s about a 1-second dropoff from lap 10 to lap 20 on the reds, and about a half-second on the primaries. The reds seemed to come back a bit near the end of the stint, but that could be drivers just pushing them to the max before pitting.
Luckily for O’Ward, he was on the primary most of the race which appears to be preferable if you want to go more than 15 laps. However, as the race went on and the traffic built up, his pace got slower and slower and his lap times more unpredictable.
When To Do An Extra Stop
This is a question that I want to do more research on, but my initial thoughts after doing this analysis are:
- You have to take track position and traffic into account. If you are going to have to re-pass more than 2 or 3 cars by pitting, it’s going to cost you a significant chunk of time. 3-stopping probably makes more sense for leaders with a big gap who want to protect against tire dropoff than it does for mid-pack trying to make a big move.
- Track length and cars on track matter. A short 70-second lap like Mid-Ohio with 27 cars on course appears to be the wrong place to do an extra stop. There’s too high a chance of coming out in traffic and dealing with backmarkers late in the race.
- Tire dropoff matters. If tire dropoff isn’t significant, then you don’t have as much to gain on fresh tires vs. worn tires. Similarly, if the difference between reds and blacks isn’t significant, then doing shorter stints on softer tires won’t be as big of an advantage.
- Cautions change everything. If more cautions had fallen later in the race, the analysis changes completely. Time lost on pit lane is mostly erased. Restarts provide easy overtaking opportunities.
Staturdays 