Multiple speed conveyor storage system

Disclosed are various embodiments for a multiple speed, multiple conveyor storage system for items in a materials handling facility such as a fulfillment center. An item storage system includes a first conveyor configured to operate at one speed, a second conveyor configured to operate at a different speed, and a transfer device configured to transfer items between the conveyors. The conveyors are each configured to store items in motion in a circuit arrangement. A computing device determines a predicted time at which the item is predicted to exit the item storage system and then initiates a transfer of the item between conveyors via the transfer device by the predicted time.