Short Leg Workout

Squats 4 x 6-10 Leg Press 3 x 12-15
Leg Curls 3 x 12-15

Leg Extensions 3 x 12-15
Standing Calf Raises 4 x 12 
Legs tend to grow more at higher rep ranges, so keep your reps +10, use good form and reasonable weight and sit back and watch your wheels grow.