Why rear tires are sliding for several Sprint Cup racers
In between the second and third NASCAR Sprint Cup Series practices at Las Vegas Motor Speedway for Sunday’s Kobalt 400 (3:30 p.m. ET, FOX), drivers took to Twitter in search of rear grip.
@ClintBowyer If you find some let me know. I am in the market as well.
— Jamie McMurray (@jamiemcmurray) March 7, 2015
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“@ClintBowyer: Well if anyone’s is selling some rear grip I’m in the market for some!” I will go half with you if you find that deal.
— AJ Allmendinger (@AJDinger) March 7, 2015
In a “NASCAR Illustrated” Q&A, No. 13 Germain Racing crew chief Robert “Bootie” Barker explained how drivers would lose grip with the new Sprint Cup Series rules package for 2015.
LOSING GRIP
“What they’re trying to do is take away downforce, make the cars lighter, take away power so we’re not going so fast in the corner,” Barker said. “Therefore, they can develop a softer tire that will wear more. So, you might run a 30-second lap on new tires, but you might run a 34-second lap on old tires. What that will promote is more sliding around, maybe more racing, maybe less dependency on all the factors we have now. In the beginning, though, you’re going to have less downforce and you’re still going to have a hard tire. That’s going to be terrible, but it’s going to take time to get there.”
Barker noted the new package will benefit some drivers while others will turn to social media, as they did today.
“Carl (Edwards) has raced dirt,” Barker said. “Kyle Larson, people like that, that will slide and don’t mind a car that’s not stuck, are going to excel. People that love them some grip and want to feel all comfy are going to be in a bad way.”
RELATED: NASCAR Illustrated: Ask a Crew Chief on 2015 Sprint Cup rules
GAINING GRIP
In another “NASCAR Illustrated” Q&A, No. 41 Stewart-Haas Racing crew chief Tony Gibson explained how the team puts mechanical grip into the car when it leaves the shop and then adjusts to aero around other cars throughout the weekend.
“When you’re balancing a race car, typically you’re by yourself,” Gibson said. “You’re on the race track and you’re not really running right behind somebody or passing somebody. They’re kind of strung out. Well, the car has max downforce and you have all the mechanical grip that you’ve built into the car for the particular race track.
RELATED: Ask a Crew Chief on aero vs. mechanical grip
“When you get in traffic, the air is so disturbed that it takes so much air off the car. Really, all you have left is the mechanical grip that you have built into it.
“We try to do our best during practice to prepare for Sunday if we have to make some changes during the race. Maybe we need to be 1.5 percent tighter mechanically to make up for being two percent looser in aero.”