FULLERTON, Calif.—Call him Yokohama Tire Corp.'s race tire maitre d'.
Perhaps it's because “senior technical engineer” doesn't roll off the tongue quite as easily, but Samuel Kwa, a four-year Yokohama veteran, prefers to be thought of simply as the person who helps choose the right tire for American Le Mans Series teams from a “menu” of assorted flavors.
“Basically, it's very similar to your selection if you walk into a restaurant and you wanted to have a meal, the maitre d' or the wine person would suggest you pair this particular wine with this particular food item,” he said. “There's not much R&D done from my perspective. I supply all the data from the teams and from the particular event.”
It sounds simple, but the process of selecting the right tire is anything but, said Kwa, who is involved with ALMS GT and GTC class races along with the IMSA GT3 Cup Challenge by Yokohama and several grassroots-level motorsports events.
For GTC class and GT3 Challenge races, both of which feature Yohohama's Advan ENV-R2 as the spec tire, Kwa said his role is pretty straightforward.
“I'm there for technical support,” he said. “Whatever questions they may have come up in regards to the tire or in regards to setting up the car for working well with the tire, I try to give as much feedback and information to the teams, the drivers, to the mechanics, just so they have a better gauge of where the car needs to be to optimize the tire.”
Things get more complicated in the GT class, Kwa said, where there is a portfolio of tire compounds from which to choose, and the crew will test a variety of these, often using a known compound from a previous race as a baseline.
“From there we'll run seven lap sprints and we'll run through the various compound selections depending on the time during practice, and we'll try to maximize our testing time to figure out what's going to work and what's not for the weekend,” he said.
Kwa's role for GT events involves obtaining lap time data, taking tire pressures and temperatures, analyzing tire wear, getting feedback from drivers and looking at other information to select the optimum compound for qualifying and race day. “We also have to consider weather that may be approaching and amount of waterfall on the ground to choose the optimum wet tire, as well,” he said.
Kwa, who also is involved with Yokohama's OTR tire segment, said the two products—while very different from each other—share a common theme.
“They're very dissimilar, but one thing that is sort of an overlapping theme is that every tire that we produce or use in motorsports and every tire that we make in OTR, there's a tire that's built specifically for a certain application.
“With the mining side of it, the OTR side, we have different applications where we need to run certain compounds or certain constructions that will work best,” he continued. “In motorsports, it's the same way. We have a tire that has a certain compound that will work with a track, a certain compound that will work with this amount of water…and we have to be able to make that judgment on the fly.”
Prepping for race day
A typical race weekend for Kwa lasts about four to five days, including a day for setup and two or three practice days. He usually shows up at the track a day before practice runs begin to perform a track characterization.
“That involves taking surface samples,” he said. “I use a quick-drying putty and I do surface impressions at various places around the track, and wherever I do a surface impression I also get a coefficient of friction measurement.
“Basically we have an ASTM standard sample we use and we compare that to a sample of the compound we're using,” he continued. “From there we can gain information about how much grip there is on the track, both mechanically and chemically. We can gauge how our compounds are going to run on the track and make a decision on what we plan to run for the track conditions that particular weekend.”
After practice days, Kwa spends more time back in his hotel room analyzing lap times and creating a report to compare the performance of each car.
Race day is often much more simple, with Kwa primarily serving in an advisory role. But in racing “nothing runs according to plan,” he said. Many factors—including changes in humidity levels, track temperature and the weather—can have an impact on how a tire will run in a race, and last-minute changes are not unheard of.
“Due to certain changes in weather, or any influences that can affect our plan, we have to be ready to account for those things and be able to make a decision with the information that is available to us,” he said. “This is where things may get difficult and rational thought and sound judgment are key. Sometimes a race can be won in making a crucial tire decision.”
Racing: the anti-9-to-5
During any given race weekend, Kwa usually leaves for the track on Tuesday and makes his return the following Sunday or Monday, depending on what day the race is. During a typical practice day he works from about 7 a.m. until 6 p.m., or even later during night practice runs.
Kwa isn't married or in a relationship—mostly because he doesn't feel he has time for one.
“Being in this position, it makes it very, very difficult to maintain a relationship, to maintain a family,” he said. “If you do have a family they have to be very supportive and very understanding about the time that is spent doing it. Most of these guys will spend between 180 to 200 days (annually) away from home.
“Most of our events are on the East Coast, so that's another thing that's difficult,” he said. “Traveling and being based on the West Coast and having to travel constantly and having to deal with the jet lag is definitely a difficult part to deal with.”
In addition to travel and long work hours, the time commitment required for Kwa's job means giving up much of his personal time. He estimated that he loses more than 50 percent of his weekends during the season.
“On the same token, the easiest thing is that during the American Le Mans Series…I actually don't mind (being away) because the group of people that are involved there and the teams that I work with, they're all very good people,” he said.
“They're all very friendly, so missing the weekend is not such a bad thing because this is another group of friends that I have, another family that I have.