Your bike should not be unstable when mounting or dismounting. Your bike may be equipped with rear leveling caps that can be adjusted should the bike sit unevenly on the floor. Should your bike need to be leveled, turn the leveling caps until the bike sits evenly on the floor.
Note: Not all XTERRA bike models are equipped with leveling caps. If you notice that your bike is unstable, relocate the bike to a location with an even surface to avoid personal injury and operational damage to the bike.