diff --git a/tire/tire_81.6_50.scad b/tire/tire_81.6_50.scad
index 58ce79b..f4c1829 100644
--- a/tire/tire_81.6_50.scad
+++ b/tire/tire_81.6_50.scad
@@ -10,11 +10,11 @@ $fn=60;
 
 R=40.8; // outer radius
 R_I=26.5; // innermost radius
-BEVEL=2;
-BEVEL_OUTER=0.8;
-THICKNESS=2.5;
-BORDER_THICKNESS=2.5;
-PROT_DEPTH=1;
+BEVEL=1;
+BEVEL_OUTER=1.4;
+THICKNESS=1.6;
+BORDER_THICKNESS=1.2;
+PROT_DEPTH=0.5;
 PROT_L_WIDTH=2;
 PROT_A_WIDTH=2;
 FIX_WIDTH=2;
@@ -34,6 +34,8 @@ CUT_O_R=2;
 SPACING=0.6;
 HOLE_RADIUS=2.4; // my Wanhao Duplicator 4 makes no errors with Slic3r, 2.4mm is ideal lego hole
 
+N_A=0;
+
 // 6-spoke variant
 N_SPOKE=6;
 CUT_ANGLE=21;
@@ -43,6 +45,7 @@ CUT_O_R=2;
 // small
 R=22;
 BEVEL=0.6;
+BEVEL_OUTER=0.8;
 THICKNESS=1.2;
 BORDER_THICKNESS=0.8;
 PROT_DEPTH=0.4;
diff --git a/track-attach.scad b/track-attach.scad
new file mode 100644
index 0000000..cde7780
--- /dev/null
+++ b/track-attach.scad
@@ -0,0 +1,27 @@
+$fn=20;
+difference() {
+  union() {
+    hull() {
+      cylinder(r=2.4, h=4);
+      translate([0, 16, 0]) cylinder(r=2.4, h=4);
+      translate([0, 0, 3]) cylinder(r=4, h=1);
+      translate([0, 16, 3]) cylinder(r=4, h=1);
+    }
+    cylinder(r=2.4, h=9);
+    translate([0, 16, 0]) cylinder(r=2.4, h=9);
+    translate([0, 0, 8.3]) hull() {
+      cylinder(r=2.8, h=1);
+      translate([0, 0, -0.6]) cylinder(r=2.4, h=1+0.6*2);
+    }
+    translate([0, 16, 8.3]) hull() {
+      cylinder(r=2.8, h=1);
+      translate([0, 0, -0.6]) cylinder(r=2.4, h=1+0.6*2);
+    }
+  }
+  translate([-4, -0.5, 8]) cube(size=[8, 1, 4]);
+  translate([-4, 16-0.5, 8]) cube(size=[8, 1, 4]);
+  translate([2.4, -4, 7]) cube(size=[2, 8, 4]);
+  translate([-2.4-2, -4, 7]) cube(size=[2, 8, 4]);
+  translate([2.4, 16-4, 7]) cube(size=[2, 8, 4]);
+  translate([-2.4-2, 16-4, 7]) cube(size=[2, 8, 4]);
+}
diff --git a/wakeboard/kicker.scad b/wakeboard/kicker.scad
new file mode 100644
index 0000000..4cac20b
--- /dev/null
+++ b/wakeboard/kicker.scad
@@ -0,0 +1,10 @@
+$fn=200;
+L=20;
+W=15;
+H=5;
+R=60;
+difference() {
+  translate([-0.5, 0, -1]) cube(size=[L+0.5, W, H+1]);
+  // circle of radius R through 2 points (0, H) and (L, 0)
+  translate([L/2 + sqrt(R*R-L*L/4-H*H/4)*sin(atan(H/L)), -0.1, H/2 + sqrt(R*R-L*L/4-H*H/4)*cos(atan(H/L))]) scale([R, 1, R]) rotate([-90, 0, 0]) cylinder(h=W+0.2, r=1);
+}