Is 26-inch or 27.5-inch better for dirt jumping?

26-inch remains the most popular choice for dirt jump riding because the smaller wheel is easier to accelerate, more compact in the air, and has a long-established parts ecosystem. 27.5-inch wheels roll slightly better through transitions and maintain momentum better, but the difference is subtle. Most experienced riders prefer 26-inch for its snappy feel and trick-friendly rotational characteristics. If you're coming from BMX, 26-inch will feel more natural. If you're coming from mountain biking, 27.5-inch may feel less dramatically different from what you're used to.