Although LSRs do not shrink in the mold, they often shrink by 2.5% -3% after demolding and cooling. Exactly how much it shrinks depends to some extent on the formulation of the compound. However, from the perspective of the mold, the shrinkage rate may be affected by several factors, including the temperature of the mold, the temperature at which the compound is released, and the pressure in the mold cavity and subsequent compression of the compound.

The location of the injection point is also worth considering, as the shrinkage in the direction of flow of the compound is usually greater than the shrinkage in the direction of flow perpendicular to the compound. The external dimensions of the product also have an impact on its shrinkage. Thicker products generally have smaller shrinkage than thinner ones. If secondary vulcanization is required, it may shrink an additional 0.5% -0.7%.