diff --git a/src/sim/car.ts b/src/sim/car.ts
index 610d9d3..3d5ef2b 100644
--- a/src/sim/car.ts
+++ b/src/sim/car.ts
@@ -149,13 +149,23 @@ const MAX_DAMAGE_PER_STEP = 0.25;
  *
  * Baseline wear is deliberately quicker than real life so decline is legible
  * within a session, but it has to stay inside what the parts economy can pay
- * for — see the reasoning on the two constants above.
+ * for. The old figures did not: tyres shed 8e-5 per metre, so twelve clean
+ * kilometres — no crashes at all — took them from new to ruined, while a
+ * two-kilometre round trip paid about 0.3 parts against 0.24 of condition
+ * spent. Driving perfectly barely broke even and one knock put you permanently
+ * behind, which is a decline with no way to arrest it rather than a decision
+ * about how hard to push the car.
+ *
+ * At a quarter of that a typical mission spends about 0.06 condition against
+ * ~0.3 parts earned, so roughly two clean runs pay for one bad crash. That is
+ * the ratio the whole risk/reward loop rests on: enough slack to gamble with,
+ * not enough to ignore.
  */
 export function applyWear(c: CarCondition, w: WearInput): CarCondition {
   const impact = w.impactForce / IMPACT_REFERENCE;
   const damage: Subsystems = {
-    engine: w.throttle * w.dt * 6e-4 + impact * 0.32,
-    tires: w.distance * 8e-5 + impact * 0.5,
+    engine: w.throttle * w.dt * 1.5e-4 + impact * 0.32,
+    tires: w.distance * 2e-5 + impact * 0.5,
     chassis: impact * 1.0,
   };
 
diff --git a/src/sim/sim.test.ts b/src/sim/sim.test.ts
index f27238b..cf41af9 100644
--- a/src/sim/sim.test.ts
+++ b/src/sim/sim.test.ts
@@ -85,6 +85,20 @@ describe('car condition', () => {
     expect(crashes).toBeGreaterThan(5);
   });
 
+  it('lets a careful driver come out ahead of the parts they are paid', () => {
+    // Two kilometres at 20 m/s with nothing hit: the shape of an ordinary
+    // mission. It has to cost distinctly less than the ~0.3 parts one pays, or
+    // driving perfectly is a losing move and the economy has no floor.
+    let c = freshCondition();
+    const steps = Math.round((2000 / 20) * 60);
+    for (let i = 0; i < steps; i++) {
+      c = applyWear(c, { dt: 1 / 60, distance: 20 / 60, throttle: 1, impactForce: 0 });
+    }
+    const spent = 3 - (c.level.engine + c.level.tires + c.level.chassis);
+    expect(spent).toBeGreaterThan(0.02);
+    expect(spent).toBeLessThan(0.12);
+  });
+
   it('makes a worn car measurably worse to drive', () => {
     const fresh = deriveHandling(freshCondition());
     const worn = deriveHandling({