Ford CEO Jacques Nasser yesterday defended to U.S. Congress the decision to replace 13-million tires made by Bridgestone/Firestone Inc., saying customers had lost faith in the tires.

Nasser’s statements came a day after Bridgestone/Firestone Inc. CEO John T. Lampe said in testimony before Congress yesterday that the company's tires are safe and again raised tough questions about the automaker’s Ford Explorer.

Wilderness AT tires had also been original equipment on Ford’s F-150 and Ranger light trucks. Lampe said the Explorer tread separation failure is eight times greater than the Ranger’s. However, Nasser told Congress that Firestone’s information is incorrect, and that the failure rate is equal.

“Firestone's analysis is flawed because it does not take into account the fact that the tire was an option on the Ranger, fewer of these tires on the Ranger went to southern states, and fewer tires on the Ranger were made in Decatur, the plant with the highest failure rate,” Ford said in a statement released after Nasser’s testimony. “When you take all these factors into account, which you must to properly complete the analysis, the failure rates between the Ranger and Explorer are not statistically different.”

The century-long relationship between Firestone and Ford, which ended last month, became strained in the past year after the recall of Firestone Wilderness AT tires linked to at least 203 U.S. traffic deaths involving Ford Explorers. Officials from Ford and Bridgestone/Firestone had exchanged blame for the tire failures since they came to light.

Commerce chairman Billy Tauzin (R-LA) said he is giving all of the claims and tread separation information gathered by the committee to Ford. Rep. Tauzin asked Ford to subject the replacement tires to the same standards as the Wilderness tires that are being replaced.

“After reviewing the tread-separation claims information provided by the committee last night, the National Highway Traffic Safety Administration (NHTSA) has now determined, as I suspected, that it needs additional time to fully evaluate the safety of these tires,” Rep. Tauzin said.

According to Rep. Tauzin, seven tire models used by Ford to replace the Firestones have failure rates exceeding Ford's desired maximum of five per million. One model, which he did not identify, had 124 claims per million, a rate 25-times higher than Ford's limit, he said.

U.S. regulators said they need more information and time to verify congressional investigators' accusations that Ford Motor Co. may be replacing good Firestone tires with ones that have higher failure rates.

DOT deputy secretary Michael Jackson told the same U.S. House Commerce panels yesterday that regulators would quickly sort out conflicting data.

“We did a quick look at the information from the committee and met with them to discuss what information is needed to make a more thorough and accurate analysis,” said Rae Tyson, a spokesman for the DOT's National Highway Traffic Safety Administration. He did not disclose what other information NHTSA is seeking.

“We've tested more tires than anybody in the history of mankind for an automaker,” said Ford spokesman Jason Vines. “We, of course, will continue to work with Mr. Tauzin. We hope he's armed with enough facts to make good decisions.”

Ford has collected data and analysis concerning its Wilderness AT tire replacement program and Explorer safety and also claims that the Wildreness AT has also proven to have tread separation while used with other SUVs.

Ford said it spent $3 billion to replace the Firestones with tires made by Goodyear Tire & Rubber Co., Michelin & Cie., and Continental AG.