The best timeframe for ADX is the daily chart, where trend signals are cleaner and less prone to whipsaws. The best time frame for trading ADX is on higher time frames like Daily, weekly and monthly.
Shorter timeframes (e.g., 5 or 15 minutes) are ideal for intraday traders, while longer timeframes (e.g., daily or weekly charts) suit swing and position traders.
Lower settings will make the average directional index respond more quickly to price movement but tend to generate more false signals.
Higher settings will minimize false signals but make the average directional index a more lagging indicator.
Match the timeframe to your holding period.