Sunday’s postponement of the Martinsville Cup race brought about a "green" track for teams to contend with. This term is coined from the condition of rain washing away tire rubber buildup from a speedway’s surface.
Any paved racetrack is susceptible to the same conditions that affect highways and streets we drive our personal vehicles on. That includes the weather. And this year’s Daytona 500 pothole was a perfect example of that.
At Martinsville, or any track that has been sitting inactive for a time period, the surface is clean from tire compounds that were laid down from the previous year. As soon as practice opens and cars start turning laps, rubber from the tires begin to work its way into the speedway.
This procedure is not the same week to week. Asphalt composition varies around the country and facilities. A few tracks have concrete surfaces. And Martinsville is unique in having blacktop straightaways and the concrete is only laid down in the corners.
A tire compound is designed for a particular track characteristic, so this also effects how they wear and rubber forms to a track surface. The testing to improve tires is steady, so tire quality usually changes at least every few years. The tires brought to Martinsville happen to be the same compounds used in 2009, so team notes will have a good point of reference.
As the track accepts more rubber particles, the car’s grip level increases. Crew chiefs call for adjustments with their minds on a two-lap qualifying run, 500 laps on race day, and the weather forecast, all at the same time.
Practice on Saturday is the closest track conditions will be to the actual race. Careful notes are taken. When a rainstorm comes in like it did Sunday and washes off all the tire rubber put down we now have a green track. Not literally the color green, but just cleaned off from practice, qualifying and support races. It more resembles the laps immediately turned a few days prior when the first practice started.
Now the task facing teams is being patient enough to let the track conditions return to the pre-rain condition, which it will during the course of an event. But don’t let the race get away by not adjusting to the early grip levels and find scoring showing your team off the lead lap. Race day after a rain delay requires excellent track observation and adjusting skills.
All racetracks are in a constant state of change. Tire rubber being stuck to the surface is a large factor of that. Race teams gain valuable tire information in practice. When it rains and the green track is presented for race day it is an unknown challenge for crew chiefs and tire specialists. But at least all teams are in the same boat.
(Patrick Reynolds is a former NASCAR mechanic who co-hosts the One and Done auto racing radio talk show Tuesdays at 11am ET. Listen at www.wsicweb.com.)
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