two wheels; two flowers
Literally 'two wheels' or 'two flowers'. The meaning depends on context: 二輪車 (two-wheeled vehicle) or 二輪の花 (two flowers).
Please park two-wheeled vehicles in the bicycle parking area.
Two roses are arranged in the vase.
二輪 is a plain count of 'two wheels', while 両輪 stresses the two wheels working together as an inseparable pair.
三輪 means three-wheeled (e.g. a tricycle), whereas 二輪 means two-wheeled (e.g. a motorcycle or bicycle), so learners may mix up which number goes with which vehicle type.
Compound of 二 (two) and 輪 (wheel or flower). The reading is the standard on'yomi.