Clue: Mongols maybe covering arid shifting sand in rattletraps (11)
Answer: SHANDRYDANS
Explanation: Definition: rattletraps
**SHAN** ("Mongols, maybe")* covering* **DRY** ("arid") + ***(sand)** [anag:*shifting*] 
*Shan is a Mongolid people, and a shandrydan is a light cart.