for best results, i would imagine it would need to set-up/cure for at least a few hours (just a guestimate). if it doesn't say on the product itself, try calling them directly. who knows, they might even answer their phone...
btw, here's a wheel coating that might be of interest in the future. not to mention, AG stands behind their products and have excellent customer service...
McKee's 37 is a nano-glass ceramic coating that provides your wheels with unparalleled protection against brake dust, dirt, road grime, oil and tar. Formulated using nano-glass ceramic particles, McKee's 37 Wheel Coating blankets your wheels in a durable, high-gloss protective barrier that resists brake-dust build up, keeping your wheels clean and protected in between regular washes. A single application lasts up to 1 year!