The best mountain bikes for downhill prioritize robust frames, long-travel suspension (180-200mm), and slack geometry. Models like the Specialized Demo or Trek Session shine with their ability to handle steep, rocky descents. Strong aluminum or carbon frames withstand abuse, while 27.5-inch or mixed wheels offer nimble control. Hydraulic disc brakes with large rotors (180-203mm) ensure reliable stopping power. A dropper post, like the RockShox Reverb, enhances maneuverability. However, these bikes are heavy and less efficient on climbs, so they’re specialized for lift-accessed or shuttle runs. Budget options, like the GT Avalanche Comp, can work for beginners but lack advanced damping. Rider skill matters more than bike cost—don’t overspend on features you won’t use.