Martin Truex Jr had 5 tires for the race that needed to be replaced
NASCAR runs inner-liners at Las Vegas Motor Speedway and just about everywhere. The only exceptions are short tracks.
The inner-liner is basically a tire within a tire. On the rim, there’s two valve stems. It’s there in the case of a flat, the car won’t abruptly spin and smack the wall. It gives the driver a chance to save it.
For setup purposes, the inner-liner runs at an increased pressure of about 12 lbs to the outer tire. You do not want the inner tire to have the same pressure as the outer tire.
But, that’s exactly what happened to Martin Truex Jr in Friday qualifying. The inner tire was leaking through the inner bead. That created a situation where both the inner tire and the outer tire had the exact same pressure. It wasn’t that the tire was flat. Just that the inner tire was leaking into the outer tire, nullifying the intended differences in pressure between the two.
Crew chief Cole Pearn kept it a secret and didn’t tell his driver. The team pleaded with NASCAR to allow them to unmount the tire and remount it to a new rim and inner tire, ahead of qualifying. They didn’t allow them to do that. Unaware of the issue, Martin Truex Jr qualified in 4th!
The right front was the issue for the #78. Cole Pearn played a trick on the tire. Before Truex would make his Q runs, Cole Pearn would air up the tire more than it needed to be. Then, just before Truex made his run, Pearn would let air out of the outer rim.
By doing that, he didn’t give the tire time to equalize. For a short 1 lap run, the tire would maintain the pressure differences between the inner and outer tire.
On Saturday, Furniture Row Racing unmounted that tire and put it on a different rim and inner liner. It took them 8 different inner liners and two different rims to solve the issue with the RF tire that was leaking in qualifying.
That same tire set from qualifying will be used to start the race. Again, Furniture Row Racing didn’t change the outer tire. It’s not a new tire and it still has the wear from qualifying, so he’ll keep his 4th place starting position. They only changed the inner-tire and rim.
Beyond that, Furniture Row Racing went to double check all the rest of their tires for the race on Sunday. They had 5 tires that were intended for the race that were doing the same thing. In addition, the tire specialist for Martin Truex Jr told Fox Sports that several other teams are fighting with the same issue.
The Pennzoil 400 from Las Vegas Motor Speedway will air at 3:30 et on FOX.