This term was coined by Eric Pollard in 2004 to describe the Prophet 130 that he designed for Line Skis.
“Early Rise” is an alternate term for “Rocker,” and holds the same meaning. People sometimes use the terms as if they signify distinctions, and in practice, people will sometimes use “early rise” to signify a relatively subtle amount of rocker, or more specifically, they’ll use “early rise” when talking about a ski that has a subtle or small amount of “Splay.”
“Splay” refers to one of two numbers used to give the exact dimensions of any ski’s rocker profile. There is not an industry standard at this point, but most commonly, the splay is measured at the end of the tip and tail. Splay is the height or total amount of rise (usually measured in mm) the rocker has over the snow surface. For example, in the above camber profile diagram of the ON3P Pillowfight, the ski’s tip rocker has 75mm of splay.
To complete the dimensions of a rocker profile, the depth of a ski’s “rockerline” must be taken into account, and to find a ski’s rockerline, we’ll need to establish the “contact points” of a ski.
A ski’s contact points are used to locate the Rocker Lines of a ski. If a pair of skis is held base to base, and is not de-cambered (i.e., is NOT pressed flat, waist to waist), you can easily find the contact points. (See Völkl diagram with marked contact points below.)
The distance from the tip or tail of the ski to these contact points defines the depth of its the rocker line.
Paired with a splay measurement of 25mm, for example, a rockerline measurement of 300mm means that a ski’s tip or tail rises a total of 25mm over a distance of 300mm. Paired together, the complete dimensions would read: 300/25.
Many companies (K2, Salomon, MOMENT, ON3P) list these measurements in a ski’s specs.
Both the rockerline depth and splay measurements of a ski’s camber profile play a significant role in determining its performance characteristics (especially when it comes to running length), and should always be taken into consideration.
This measurement is used to find the distance between the contact point of the shovel to the contact point of the tail, and will tell you how functionally “long” the ski is (i.e., how much of the ski is actually in contact with the snow when skied bases flat).
The Running Length measurement allows you to easily compare lengths between models that have varying amounts of rocker, since a heavily rockered 190cm ski will feel more similar on firm snow to a less dramatically rockered 184cm ski.
For now, we’re going to leave things there. Hopefully this helps to clarify some of the relevant ideas and terms surrounding this whole rocker thing, and we’ll pick up on these themes soon with a more in-depth article on ski shaping and design.