Because the cylinder wall is exposed to constant friction from the piston, a steel sleeve is inserted in the cylinder to achieve high abrasion resistance. If the sleeve is eliminated in order to improve heat dissipation, the aluminum cylinder by itself doesn’t have the strength to provide sufficient abrasion resistance. To solve this problem DiASil Cylinder adds a silicon content of 20% (twice that of regular aluminum) to the aluminum alloy to achieve the required hardness to resist abrasion.