diff --git a/ai_docs/solver_calc_position.c b/ai_docs/solver_calc_position.c
index 3d3a49e2b..1ce6ef8d2 100644
--- a/ai_docs/solver_calc_position.c
+++ b/ai_docs/solver_calc_position.c
@@ -141,6 +141,18 @@ parse_cfg_line(const char *line, struct cfg_state *cfg)
     return 1;
 }
 
+static double
+gear_ratio(const struct cfg_state *cfg)
+{
+    double motor_gear = cfg->motor_gear;
+    if (motor_gear == 0.)
+        motor_gear = 1.;
+    double gear = cfg->spool_gear / motor_gear;
+    if (gear <= 0.)
+        gear = 1.;
+    return gear;
+}
+
 static double
 rotation_distance_for_axis(const struct cfg_state *cfg, size_t idx)
 {
@@ -148,8 +160,8 @@ rotation_distance_for_axis(const struct cfg_state *cfg, size_t idx)
     double ma = cfg->mech_adv[idx];
     if (ma == 0.)
         ma = 1.;
-    double gear = cfg->spool_gear / cfg->motor_gear;
-    return (2.0 * M_PI * r) / (gear * ma);
+    // Use circumference/mechanical advantage; gear ratio is handled via steps_per_rotation.
+    return (2.0 * M_PI * r) / ma;
 }
 
 static int
@@ -179,11 +191,13 @@ solve_sample(const struct cfg_state *cfg, size_t num, int use_flex,
         mech_adv);
     winch_flex_set_enabled(wf, use_flex ? 1 : 0);
 
+    double gear = gear_ratio(cfg);
     double motor_mm[WINCH_MAX_ANCHORS];
     for (size_t i = 0; i < num; ++i) {
         double rd = rotation_distance_for_axis(cfg, i);
-        winch_flex_set_spool_params(wf, (int)i, rd, cfg->steps_per_rev);
-        motor_mm[i] = motor_deg[i] / cfg->steps_per_rev * rd;
+        double steps_per_rotation = cfg->steps_per_rev * gear;
+        winch_flex_set_spool_params(wf, (int)i, rd, steps_per_rotation);
+        motor_mm[i] = motor_deg[i] / cfg->steps_per_rev * (rd / gear);
     }
 
     struct timespec t0, t1;
diff --git a/klippy/chelper/kin_winch.c b/klippy/chelper/kin_winch.c
index 059076a61..ed5bb4efd 100644
--- a/klippy/chelper/kin_winch.c
+++ b/klippy/chelper/kin_winch.c
@@ -610,7 +610,10 @@ compute_flex(struct winch_flex *wf, double x, double y, double z,
         if (spring_length < EPSILON)
             spring_length = EPSILON;
         double spring_k = wf->spring_constant / spring_length;
-        flex[i] = -forces[i] / spring_k;
+        double ma = wf->mechanical_advantage[i];
+        if (ma <= 0.)
+            ma = 1.;
+        flex[i] = -forces[i] / (spring_k * ma);
     }
 }