A character can use spikes (pitons) to increase the number of foot-holds available to him/her (and hence make it easier for him/her to successfully climb). To place a spike successfully, the character must make a dice roll using his/her ST + Climbing (including Using spikes specialism) at a difficulty value of 4. A separate dice roll must be made for each spike - success means the spike is well-positioned, failure means that it is wasted.
When a character follows a path up a climb on which there are well-placed spikes, he/she gains a +1/2 modifier on that minute's climbing safely dice roll for every spike that he/she passes in that minute.
Each spike takes 30 seconds to hammer in, though a character can reduce this time by the result of a dice roll using his/her ST + Climbing (including Using spikes specialism) in seconds. Spikes cannot be re-used after they have been hammered in.
For example, Urlik is a good climber with a Climbing skill of 3 with 2 points of specialism in Climbing safety (a broad specialism) and none in using spikes. He has a CO score of +1 and a ST score of +1 and is lightly encumbered (giving him a +1 bonus on all dice rolls based on CO). His basic value for climbing safely (see above) is 3+1+1 +1 = 6, which gives him a guaranteed dice roll result of 6. Unfortunately, he is climbing a rock face of difficulty 7. Fortunately, he has some spikes to hand. For using spikes, Urlik's basic value is 3+1=4, giving him a guaranteed dice roll result of 4, exactly what he needs. Each spike takes him approximately 26 seconds (30-4) to hammer in. He hammers in two spikes, giving him a +1 modifier to his climbing safely dice roll, which takes his climbing safely basic value to 7, giving an automatic dice roll result of 7.