Verizon Wireless is feeling the crush of all of those LTE-enabled devices on its network. The carrier said it is facing pressure to deliver increased amounts of bandwidth in big cities such as New York, San Francisco, and Chicago. In a rare admission on Tuesday, Verizon Chief Financial Officer Fran Shammo admitted the rapid growth in traffic was starting to hamper the quality of the service. “There are certain pockets where we’re absolutely going to experience that down tick from the LTE network down to 3G because of capacity constraints,” Shammo said during an investor conference. It’s a surprising concession from a company that typically trumps its network superiority as a reason why customers should pay a premium for its wireless services. It has long touted itself as the nation’s most reliable, but that claim has since been taken by AT&T, which also boasts the nation’s fastest network.