A process for continuously preparing copolyamides by copolymerizing at least one lactam (A) and monomers (M), comprising the steps of a) mixing at least one lactam (A) with monomers (M) at a temperature of 60 to 150° C. and b) passing the mixture obtained in step a) from the top downward through a vertical polymerization tube at polyamide-forming temperatures to obtain a copolyamide, wherein the monomers (M) comprise at least one C32-C40 dimer acid (B1) and at least one C4-C12 diamine (B2) and optionally at least one C4-C20 diacid (B3).