Abstract: The stabilizer, in a preferred embodiment thereof, comprises a generally tubular body which is axially slit, as in the prior art. According to one practice of the invention, the surfaces of the body immediately adjacent to the slit have ribs formed thereon which define bearing surfaces for clamping together, to draw the surfaces into proximity, narrowing the slit, thereby to contract the stabilizer to a constrained dimension approximately eight percent smaller than its free dimension. This is done to facilitate its insertion into an undersized bore. The novel method, then, in an embodiment thereof, comprises contracting an axially slit friction rock stabilizer by engaging the aforesaid ribs (formed thereon) with a tool, to contract the stabilizer to a reduced and constrained, approximately eight percent smaller, cross-sectional dimension, inserting the stabilizer into an undersized bore, and withdrawing the tool.