NASCAR's current testing policy does not allow teams to test at tracks included in the Sprint Cup calendar but Goodyear carries out a number of tests to finalise tyre selections for future events and a small group of drivers are selected to participate by the tyre firm.
On 4 August, five weeks away from the start of the Chase, two drivers represented each of the four manufacturers in a test at Dover, where Goodyear was hoping to rectify some wear issues it had during the autumn race at the same track.
Reigning champion Johnson was among those selected to test, something Biffle believes to be an unfair advantage.
"I'd say if they called me to test tyres for any of these eight races I'd love to do it," said Biffle. "I think we should level the playing field. There are 12 Chase drivers and we've got eight races left, so I'd be more than happy to go test somewhere.
"We've addressed this several times but they just continue to do what they want to do, however their selection process is, I don't know how that works. It's been implied before that they don't want Chase drivers testing for the Chase races.
"I understand they struggle because they've got to get good cars, fast competitive cars that they can trust the data from. But that selection process has to be refined somewhere.
"They can't do the test way early, they've got to do it closer to the race. They're backed in a corner, I understand that but you know, they need to do it either let us all [Chase drivers] test at the track or not let any of us. That's all I'm saying."
Robin Pemberton, NASCAR's vice president for competition, said it was up to Goodyear to select the drivers it wants to take to each of its tests in order to get the best possible data, which should reflect in the best tyre selection from the teams, drivers and the tyre manufacturer.
"There'll always be sour grapes among some of [the teams] that will complain about who gets to test when and where," said Pemberton. "But the goal is to take good guys that get good feedback for Goodyear to get the best test. If you take people that would not contribute to that test, then you'll wind up with a less than favourable tyre."
Johnson, who ran a dominant race at Dover back in May on his way to his second win of the season, said it was not his fault he was selected by Goodyear to participate in the test, which he admits was an advantage.
"[Biffle] could be really upset because had the #18 [Kyle Busch] made [the Chase] it would have been three cars doing the test," said Johnson. "Everybody has an opinion and Goodyear contacts us and tells us where they'd like to use us and that's how it goes.
"I didn't get a chance to test Indy. I know there's cars that tested Indy and ran laps and miles and the #48 didn't go. So you just go where they tell you to go run and test.
"We tested here, it was our perk and there's no doubt that there's an advantage to it. But we overcame that at Indy and didn't have a chance to test there and went up there and won the show."
Juan Pablo Montoya, who qualified on the front row for Sunday's race, was the other Chevrolet representative in the tyre test. He downplayed the advantage of being in there, saying that most of the work was carried out by Johnson and his Hendrick team, while his Earnhardt Ganassi squad played a secondary role.
"Most of the tyre test was done actually by Jimmie," said Montoya, who suffered a number of tyre problems during the autumn event at the track. "Jimmie and [AJ] Allmendinger were the primary cars on the tyre test. We were secondary and for us it was mainly, they asked us to do long runs to rubber up the track.
"Did it help? I don't know. I qualified third here last time."
Last year Biffle made similar comments after Kyle Busch was among a number of drivers testing at Atlanta before the series raced there during the Chase, where both him and Busch were title contenders.
Bobby Labonte and David Ragan represented Ford at last month's test at Dover, Dodge had Allmendinger and David Stremme, while Toyota had Kyle Busch and Marcos Ambrose.
However, none of them qualified among the top 10 for Sunday's race at Dover.
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