I am a girl, I weigh 125lbs and I'm 5' 9". I can ski most black runs comfortably; and I was wondering which size I should buy. The all-mountain skis I have now are 158 cm and I was wondering if I would be able to handle something in the 170 range, or if I should go smaller?

Im 5'3 and have the skis in the 172. I highly suggest the 172 for you due to your weight, height, and what style of skiing you do. As said above, the more aggressive skier, generally the longer the ski. You seem to be able to handle lots of terrain and the 172 will have enough length so you will be able to charge on them everywhere, but they won't be too long that you will feel overpowered in crud and making tighter turns. I think you will love the 172!

I'm about 5'7 and 120 pounds and charge Jackson hole with a 172 bacon. 10 cm does not make much of a difference so you can't go wrong between a 172 or a 182

they are all on crack... 172 is going to be a bit long and bulky for you if you are 125 and a girl. Guys tend to have more muscle mass and being smaller 5'7" 145 I stick to 177cm or under even for pow... and I charge with dins cranked at 13. Where you mount your bindings will also make the ski ride smaller if they are close to true center or center. If you are using this as your all-mountain go shorter(162), for pow only/mostly go bigger (172). However, you should really try and demo a pair of 162s before you purchase. Although lifetime return policy sooo....

172's will be small. remember they have early rise so they will ski shorter than they are. i suggest 182 if your 5'9

Write your answer here...get the 172s they would be good

Go at least 172. Possibly 182 if you think you will start skiing much faster and harder.