diff --git a/mobile/app/activity/[id].tsx b/mobile/app/activity/[id].tsx
index 10b0a8b..3d73e70 100644
--- a/mobile/app/activity/[id].tsx
+++ b/mobile/app/activity/[id].tsx
@@ -11,7 +11,11 @@ const MAP_STYLE = 'https://basemaps.cartocdn.com/gl/dark-matter-gl-style/style.j
 
 type Timeseries = {
   t: number[];
-  elevation_m: (number | null)[];
+  elevation_m:  (number | null)[];
+  speed_kmh?:   (number | null)[] | null;
+  hr_bpm?:      (number | null)[] | null;
+  cadence_rpm?: (number | null)[] | null;
+  power_w?:     (number | null)[] | null;
   lat?: (number | null)[] | null;
   lon?: (number | null)[] | null;
 };
@@ -104,8 +108,8 @@ export default function ActivityScreen() {
         {power       && <StatCell label="Avg power"      value={String(power)} unit="W" />}
       </View>
 
-      {/* Elevation chart */}
-      <ElevationChart timeseries={timeseries} loading={loadingChart} />
+      {/* Metric charts */}
+      <MetricCharts timeseries={timeseries} loading={loadingChart} />
 
       {/* Meta */}
       <View style={styles.meta}>
@@ -188,12 +192,20 @@ function RouteMap({ geojson, loading }: { geojson: object | null; loading: boole
   );
 }
 
-// ── Elevation chart ───────────────────────────────────────────────────────────
+// ── Metric charts ─────────────────────────────────────────────────────────────
 
-function ElevationChart({ timeseries, loading }: { timeseries: Timeseries | null; loading: boolean }) {
-  const W = 340;
-  const H = 100;
-  const PAD = 4;
+type TabKey = 'elevation' | 'speed' | 'hr' | 'cadence' | 'power';
+
+const TAB_META: Record<TabKey, { label: string; unit: string; color: string; decimals: number }> = {
+  elevation: { label: 'Elevation', unit: 'm',     color: '#00c8ff', decimals: 0 },
+  speed:     { label: 'Speed',     unit: 'km/h',  color: '#ff6b35', decimals: 1 },
+  hr:        { label: 'HR',        unit: 'bpm',   color: '#f87171', decimals: 0 },
+  cadence:   { label: 'Cadence',   unit: 'rpm',   color: '#a78bfa', decimals: 0 },
+  power:     { label: 'Power',     unit: 'W',     color: '#facc15', decimals: 0 },
+};
+
+function MetricCharts({ timeseries, loading }: { timeseries: Timeseries | null; loading: boolean }) {
+  const [activeTab, setActiveTab] = useState<TabKey>('elevation');
 
   if (loading) {
     return (
@@ -204,41 +216,94 @@ function ElevationChart({ timeseries, loading }: { timeseries: Timeseries | null
   }
   if (!timeseries) return null;
 
-  const raw = timeseries.elevation_m;
-  if (!raw || raw.length < 2) return null;
+  const seriesMap: Record<TabKey, (number | null)[] | null | undefined> = {
+    elevation: timeseries.elevation_m,
+    speed:     timeseries.speed_kmh,
+    hr:        timeseries.hr_bpm,
+    cadence:   timeseries.cadence_rpm,
+    power:     timeseries.power_w,
+  };
 
-  // Downsample to ≤300 points
-  const step  = Math.max(1, Math.floor(raw.length / 300));
-  const times = timeseries.t.filter((_, i) => i % step === 0);
-  const eles  = raw.filter((_, i) => i % step === 0).map(v => v ?? 0);
+  const available = (Object.keys(TAB_META) as TabKey[]).filter(
+    k => seriesMap[k]?.some(v => v != null)
+  );
 
-  const minE  = Math.min(...eles);
-  const maxE  = Math.max(...eles);
-  const range = maxE - minE || 1;
-  const maxT  = times[times.length - 1] || 1;
+  if (!available.length) return null;
 
-  const x = (t: number) => PAD + (t / maxT) * (W - PAD * 2);
-  const y = (e: number) => PAD + (1 - (e - minE) / range) * (H - PAD * 2);
-
-  const pts = times.map((t, i) => `${x(t).toFixed(1)},${y(eles[i]).toFixed(1)}`);
-  const linePath  = `M ${pts.join(' L ')}`;
-  const areaPath  = `M ${x(times[0])},${H} L ${pts.join(' L ')} L ${x(maxT)},${H} Z`;
+  const tab = available.includes(activeTab) ? activeTab : available[0];
+  const { color, unit, decimals } = TAB_META[tab];
+  const raw = seriesMap[tab]!;
 
   return (
     <View style={styles.chartContainer}>
-      <Text style={styles.chartLabel}>{Math.round(maxE)} m</Text>
+      {/* Tab row */}
+      <View style={styles.chartTabs}>
+        {available.map(k => (
+          <Pressable
+            key={k}
+            style={[styles.chartTab, tab === k && { borderBottomColor: TAB_META[k].color, borderBottomWidth: 2 }]}
+            onPress={() => setActiveTab(k)}
+          >
+            <Text style={[styles.chartTabText, tab === k && { color: TAB_META[k].color }]}>
+              {TAB_META[k].label}
+            </Text>
+          </Pressable>
+        ))}
+      </View>
+      {/* Chart */}
+      <MetricChart key={tab} times={timeseries.t} values={raw} color={color} unit={unit} decimals={decimals} />
+    </View>
+  );
+}
+
+function MetricChart({
+  times, values, color, unit, decimals,
+}: {
+  times: number[];
+  values: (number | null)[];
+  color: string;
+  unit: string;
+  decimals: number;
+}) {
+  const W = 340;
+  const H = 100;
+  const PAD = 4;
+
+  // Downsample to ≤300 points
+  const step = Math.max(1, Math.floor(values.length / 300));
+  const ts   = times.filter((_, i) => i % step === 0);
+  const vs   = values.filter((_, i) => i % step === 0).map(v => v ?? 0);
+
+  const minV = Math.min(...vs);
+  const maxV = Math.max(...vs);
+  const range = maxV - minV || 1;
+  const maxT  = ts[ts.length - 1] || 1;
+
+  const x = (t: number) => PAD + (t / maxT) * (W - PAD * 2);
+  const y = (v: number) => PAD + (1 - (v - minV) / range) * (H - PAD * 2);
+
+  const pts      = ts.map((t, i) => `${x(t).toFixed(1)},${y(vs[i]).toFixed(1)}`);
+  const linePath = `M ${pts.join(' L ')}`;
+  const areaPath = `M ${x(ts[0])},${H} L ${pts.join(' L ')} L ${x(maxT)},${H} Z`;
+  const gradId   = `grad-${color.replace('#', '')}`;
+
+  const fmt = (v: number) => decimals === 0 ? String(Math.round(v)) : v.toFixed(decimals);
+
+  return (
+    <>
+      <Text style={[styles.chartLabel, { color }]}>{fmt(maxV)} {unit}</Text>
       <Svg width={W} height={H} viewBox={`0 0 ${W} ${H}`}>
         <Defs>
-          <LinearGradient id="grad" x1="0" y1="0" x2="0" y2="1">
-            <Stop offset="0" stopColor="#60a5fa" stopOpacity="0.35" />
-            <Stop offset="1" stopColor="#60a5fa" stopOpacity="0.02" />
+          <LinearGradient id={gradId} x1="0" y1="0" x2="0" y2="1">
+            <Stop offset="0" stopColor={color} stopOpacity="0.35" />
+            <Stop offset="1" stopColor={color} stopOpacity="0.02" />
           </LinearGradient>
         </Defs>
-        <Path d={areaPath} fill="url(#grad)" />
-        <Path d={linePath}  fill="none" stroke="#60a5fa" strokeWidth="1.5" strokeLinejoin="round" />
+        <Path d={areaPath} fill={`url(#${gradId})`} />
+        <Path d={linePath} fill="none" stroke={color} strokeWidth="1.5" strokeLinejoin="round" />
       </Svg>
-      <Text style={styles.chartLabel}>{Math.round(minE)} m</Text>
-    </View>
+      <Text style={[styles.chartLabel, { color: '#3f3f46', marginBottom: 10 }]}>{fmt(minV)} {unit}</Text>
+    </>
   );
 }
 
@@ -311,9 +376,12 @@ const styles = StyleSheet.create({
   fullscreenMap:   { flex: 1, backgroundColor: '#09090b' },
   closeButton:     { position: 'absolute', top: 56, right: 16, backgroundColor: 'rgba(0,0,0,0.6)', borderRadius: 20, width: 36, height: 36, alignItems: 'center', justifyContent: 'center' },
   closeText:       { color: '#fff', fontSize: 16 },
-  chartContainer: { marginHorizontal: 16, marginBottom: 16, backgroundColor: '#18181b', borderRadius: 10, borderWidth: 1, borderColor: '#27272a', padding: 12, alignItems: 'flex-start' },
+  chartContainer:   { marginHorizontal: 16, marginBottom: 16, backgroundColor: '#18181b', borderRadius: 10, borderWidth: 1, borderColor: '#27272a', overflow: 'hidden' },
   chartPlaceholder: { height: 120, backgroundColor: '#18181b', alignItems: 'center', justifyContent: 'center', borderRadius: 10, borderWidth: 1, borderColor: '#27272a', marginHorizontal: 16, marginBottom: 16 },
-  chartLabel:     { color: '#3f3f46', fontSize: 10, marginBottom: 2 },
+  chartTabs:        { flexDirection: 'row', borderBottomWidth: 1, borderBottomColor: '#27272a' },
+  chartTab:         { flex: 1, paddingVertical: 8, alignItems: 'center', borderBottomWidth: 2, borderBottomColor: 'transparent' },
+  chartTabText:     { color: '#52525b', fontSize: 11, fontWeight: '600' },
+  chartLabel:       { color: '#3f3f46', fontSize: 10, marginBottom: 2, marginHorizontal: 12, marginTop: 10 },
   grid:           { flexDirection: 'row', flexWrap: 'wrap', paddingHorizontal: 12, gap: 8, marginBottom: 16 },
   statCell:       { backgroundColor: '#18181b', borderRadius: 10, borderWidth: 1, borderColor: '#27272a', padding: 14, width: '47%' },
   statValueRow:   { flexDirection: 'row', alignItems: 'baseline', gap: 4, marginBottom: 4 },