Bicycle hub assembly whose length is adjustable

A hub assembly for a bicycle comprising:

• a shaft;
• a hub body rotatably mounted on the shaft;
• a drive seat rotatably mounted on the shaft and engaging the hub body;
• a first bearing mounted in the hub body and located between the shaft and the hub body;
• a second bearing mounted in the hub body and located between the shaft and the hub body;
• and
• a bushing unit mounted on the shaft and located between the first bearing and the second bearing;
• wherein the bushing unit includes:
• a first adjusting sleeve;
• and
• a second adjusting sleeve adjustably connected with the first adjusting sleeve;
• wherein the first adjusting sleeve of the bushing unit has a first end provided with an outer threaded portion and a second end abutting the first bearing;
• wherein the second adjusting sleeve of the bushing unit has a first end provided with an inner threaded portion screwed onto the outer threaded portion of the first adjusting sleeve and a second end abutting the second bearing, wherein:
• the first adjusting sleeve of the bushing unit has a peripheral wall provided with a plurality of first adjusting holes;
• the first adjusting holes of the first adjusting sleeve are located at the second end of the first adjusting sleeve;
• the second adjusting sleeve of the bushing unit has a peripheral wall provided with a plurality of second adjusting holes;
• and
• the second adjusting holes of the second adjusting sleeve are located at the second end of the second adjusting sleeve.