It's hoped the ride will attract 3500 participants.
Knight said: "This is a wonderful day for the state of Oregon. We have many endorsees [ie sponsored athletes], but Lance is special. He is hope in human form."
Nike was one of the few sponsors which stuck with Armstrong when he was diagnosed with cancer in 1996.
Proceeds for the ride will benefit the Lance Armstrong Foundation and Oregon Health & Science University Cancer Institute. Dr. Craig Nichols, head of the OHSU's oncology department is an honourary chair for the event. Nichols was the cancer specialist who treated Armstrong's testicular cancer.
With a $150 registration fee and incentives to raise additional funds, participants will receive awards based on the amount of money that they raise, such as invitations to the pre-ride pasta dinner and a preferred starting line position at the ride.
There's to be a Livestrong expo area and live music. Sheryl Crow may headline at the first ride.
There are 10, 40, 70 and 100-mile routes.
Further Livestrong rides will be announced next year.
The first Livestrong ride is modelled on Armstrong's Ride for the Roses ride in his hometown of Austin, Texas.