Some people told me that Hero Duet vibrates while riding, is it true?

The Hero Duet rides very well. The handling and ride quality are well balanced, and quite comfortable. No vibrations are felt when bike is idle or moving. The bike's telescopic front suspension and the hydraulic spring at the rear are very effective, and do their job pretty well. So you don't need to worry about vibrations, the Duet offers a well balanced ride.