Climbing Carstensz is held to have the highest technical rating, though not the greatest physical demands of that list's ascents. (However, you need great physical preparation for the trekking). The standard route, which is all hard rock surface, is up the north face and along the summit ridge.
The rock climbing difficulty on Carstensz is up to 5.8 for short steps, but most of the climbing is scrambling. It is important that you have basic rock climbing skills and are familiar with rappelling and jumaring. Short technical sections will need fixed lines allowing you to either free climb on top rope or jumar. You need to know how to jumar. Although there are many fixed ropes on the route, the crux involves abseiling into and jumaring out of a notch on the ridge.
Carstensz Pyramid climbing is using fixed rope, artificial climbing skills is very important here. Please pay attention to the recommended climbing equipment, make sure you bring everything in that list. These will provide safety climbing and best summit chance.
First pitch for the first rope is 1.5 hours from the Base Camp, walking up to the foot step of the summit. Climbing the first rope will need ascender to climb up 55? wall for about 60m high. You will do this climbing trough some rope until you get the big terrace, this flat terrace give rest advantage before start summit pitch. To get the summit pitch will be need 15 minutes walk on rock (basically the terrain is rock, sharp and wet).
Ascending to summit will be more difficult with up to 60? wall and 45-50m high, this will take you to summits ridge. Safe your power by moving slowly but sure or follow your optimum tempo. From the summit ridge you can see the landscape of mining below, the virgin rain forest jungle of Papua. However you can all of these only in the clear day and no cloud below the summit ridge.
You are walking on the Ridge to get the Carstensz Pyramid Summit, the path here is only 2-3m wide - walk carefully. From this point need about 1,5 hours to the summit. Before get the summit the climbing will be more difficult, you should pass 3 creck. There is two options to pass these creck, with higher difficulty level then the first climbing. First is rappelling down, walk pass the bottom of this creck and ascend in a vertical ascending (about 8m). The other way is crossing this by a line bridge using pulley and belay rope. This is very interesting and challenging part. After pass this most difficult part, you are in the summit step.
The way back is more easy, usually need only half from the climbing time to the summit. However, you need more concentration after spending much power to get the summit.