Increase in the price of skateboard wheels cause a decrease/no change in the demand of skateboards? (2 separate markets w/ 2 separate buyers)
Since there is no change in consumer preferences, the demand function will not change.
The firms supplying skateboards face increased costs due to the wheels being more expensive. This will alter their supply function and thus the equilibrium price in the skateboard market may change, and hence the equilibrium quantity demanded may also change.