An end closure (260,460) dimensioned to secure an associated flexible spring member (206,406) that is in at least a substantially-cured condition along an associated gas spring end member (204,404), said end closure (260,460) comprising an end closure wall (296,496) having a longitudinal axis and including: an end wall portion (298,498) disposed transverse to said longitudinal axis and dimensioned for securement in abutting engagement with the associated end member (204,404); a first side wall portion (300,500) disposed radially outward of said longitudinal axis and having a first cross-sectional dimension, said first side wall portion (300,500) extending from along said end wall portion (298,498) in a first axial direction, characterised in that a second side wall portion (304,504) disposed radially inward of said first side wall portion (300,500) and having a second cross-sectional dimension that is less than said first cross-sectional dimension, said second side wall portion (304,504) extending from along said first side wall portion (300,500) in at least said first axial direction and in axially-offset relation to said end wall portion (298,498) such that said first side wall portion (300,500) is positioned axially between said end wall portion (298,498) and said second side wall portion (304,504); and, at least one of a flange wall portion (314,514) and a shoulder wall portion (318,518) extending radially outward from along said second side wall portion (304,504) in at least said first axial direction and in axially-offset relation to said first side wall portion (300,500) such that a mounting seat (308,508) is at least partially formed by said second side wall portion (304,504) between said first side wall portion (300,500) and said at least one of said flange wall portion (314,514) and said shoulder wall portion (318,518), said mounting seat (308,508) dimensioned for an associated end (258,458) of the associated flexible spring member (206,406) to be stretched over one of said first side wall portion (300,500) and said at least one of said flange wall portion (314,514) and said shoulder wall portion (318,518) and into said mounting seat (308,508) to thereby form a substantially fluid-tight, friction-fit connection between at least said second side wall portion (304,504) of said end closure (260,460) and the associated flexible spring member (206,406). an end wall portion (298,498) disposed transverse to said longitudinal axis and dimensioned for securement in abutting engagement with the associated end member (204,404); a first side wall portion (300,500) disposed radially outward of said longitudinal axis and having a first cross-sectional dimension, said first side wall portion (300,500) extending from along said end wall portion (298,498) in a first axial direction, characterised in that a second side wall portion (304,504) disposed radially inward of said first side wall portion (300,500) and having a second cross-sectional dimension that is less than said first cross-sectional dimension, said second side wall portion (304,504) extending from along said first side wall portion (300,500) in at least said first axial direction and in axially-offset relation to said end wall portion (298,498) such that said first side wall portion (300,500) is positioned axially between said end wall portion (298,498) and said second side wall portion (304,504); and, at least one of a flange wall portion (314,514) and a shoulder wall portion (318,518) extending radially outward from along said second side wall portion (304,504) in at least said first axial direction and in axially-offset relation to said first side wall portion (300,500) such that a mounting seat (308,508) is at least partially formed by said second side wall portion (304,504) between said first side wall portion (300,500) and said at least one of said flange wall portion (314,514) and said shoulder wall portion (318,518), said mounting seat (308,508) dimensioned for an associated end (258,458) of the associated flexible spring member (206,406) to be stretched over one of said first side wall portion (300,500) and said at least one of said flange wall portion (314,514) and said shoulder wall portion (318,518) and into said mounting seat (308,508) to thereby form a substantially fluid-tight, friction-fit connection between at least said second side wall portion (304,504) of said end closure (260,460) and the associated flexible spring member (206,406).