The behavior of spokes in Saturn's B ring

► We observe spokes form with radial expansion rates at each end of ∼0.5 km per second. ► Typical spokes either increase or decrease in optical depth, with few unchanging. ► Edge shear rates require large charge-to-mass ratios or a spoke-forming wave front. ► Spoke activity exhibits SKR periodicities with possible variations between ring sides. ► We determine the magnetic longitude of the peak spoke activity.