diff --git a/README.md b/README.md
index 6d94199..f8cd0d9 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@
   - tendon (`BE`) with automatic coupling to `AD`
   - defaults normalized to a `45 cm` leg baseline while preserving original mechanism ratios
   - mirrored automatically to far side (180° phase side)
-- Presets save/load for named dimension setups (persisted in browser local storage).
+- Presets tab for built-in MuJoCo playback traces (10cm/20cm/30cm).
 - Foot trajectory traces for both sides.
 - Optional linkage annotation overlay (joint and link labels).
 - Optional real-time 3D viewport with orbit camera and camera reset.
diff --git a/src/main.js b/src/main.js
index b9765eb..305fcce 100644
--- a/src/main.js
+++ b/src/main.js
@@ -6,8 +6,6 @@ import { clearTrace, createTraceBuffer, pushTrace } from './trace.js';
 import { updateDiagnostics, wireUI } from './ui.js';
 import { BASE_DIMENSIONS_CM } from './geometry.js';
 
-const PRESET_STORAGE_KEY = 'walkerSim.presets.v1';
-
 const DEFAULT_LENGTH_CM = {
   crank: BASE_DIMENSIONS_CM.crank,
   leg: BASE_DIMENSIONS_CM.leg,
@@ -15,12 +13,12 @@ const DEFAULT_LENGTH_CM = {
   body: BASE_DIMENSIONS_CM.body,
 };
 
-const BUILTIN_PRESET_NAME = 'Default 45cm leg';
 const MUJOCO_TRACE_PRESETS = {
-  'MuJoCo 10cm trace': './sim/mujoco/model/mujoco_trace_10cm.json',
-  'MuJoCo 20cm trace': './sim/mujoco/model/mujoco_trace_20cm.json',
   'MuJoCo 30cm trace': './sim/mujoco/model/mujoco_trace_30cm.json',
+  'MuJoCo 20cm trace': './sim/mujoco/model/mujoco_trace_20cm.json',
+  'MuJoCo 10cm trace': './sim/mujoco/model/mujoco_trace_10cm.json',
 };
+const DEFAULT_MUJOCO_TRACE_PRESET = 'MuJoCo 30cm trace';
 
 const canvas = document.getElementById('sim-canvas');
 const view3dPanelEl = document.getElementById('view-3d-panel');
@@ -283,11 +281,6 @@ function currentLengthScale() {
   };
 }
 
-function sanitizePresetName(name) {
-  if (typeof name !== 'string') return '';
-  return name.trim().slice(0, 40);
-}
-
 function resetSimulation({ clearLengths = false } = {}) {
   if (clearLengths) {
     state.lengthCm = { ...DEFAULT_LENGTH_CM };
@@ -307,52 +300,6 @@ function resetSimulation({ clearLengths = false } = {}) {
   state.pose = applyGrounding(raw);
 }
 
-function loadPersistedPresets() {
-  const presets = {
-    [BUILTIN_PRESET_NAME]: { ...DEFAULT_LENGTH_CM },
-  };
-
-  let parsed = null;
-  try {
-    parsed = JSON.parse(localStorage.getItem(PRESET_STORAGE_KEY) ?? 'null');
-  } catch {
-    parsed = null;
-  }
-
-  if (parsed && typeof parsed === 'object' && !Array.isArray(parsed)) {
-    for (const [rawName, rawPreset] of Object.entries(parsed)) {
-      const name = sanitizePresetName(rawName);
-      if (!name || !rawPreset || typeof rawPreset !== 'object') continue;
-
-      const crank = Number(rawPreset.crank);
-      const leg = Number(rawPreset.leg);
-      const tendon = Number(rawPreset.tendon);
-      const body = Number(rawPreset.body);
-
-      if ([crank, leg, tendon, body].every(Number.isFinite)) {
-        presets[name] = { crank, leg, tendon, body };
-      }
-    }
-  }
-
-  return presets;
-}
-
-function persistPresets() {
-  const serializable = {};
-  for (const [name, preset] of Object.entries(state.presets)) {
-    if (name === BUILTIN_PRESET_NAME) continue;
-    serializable[name] = {
-      crank: preset.crank,
-      leg: preset.leg,
-      tendon: preset.tendon,
-      body: preset.body,
-    };
-  }
-  localStorage.setItem(PRESET_STORAGE_KEY, JSON.stringify(serializable));
-}
-
-state.presets = loadPersistedPresets();
 refreshLayoutMode();
 
 const ui = wireUI(state, {
@@ -363,24 +310,6 @@ const ui = wireUI(state, {
   refresh() {
     resetSimulation({ clearLengths: false });
   },
-  savePreset(name) {
-    const presetName = sanitizePresetName(name);
-    if (!presetName) return null;
-    state.presets[presetName] = { ...state.lengthCm };
-    persistPresets();
-    return presetName;
-  },
-  loadPreset(name) {
-    const presetName = sanitizePresetName(name);
-    const preset = state.presets[presetName];
-    if (!preset) return false;
-    state.lengthCm = { ...preset };
-    resetSimulation({ clearLengths: false });
-    return true;
-  },
-  listPresets() {
-    return Object.keys(state.presets);
-  },
   listMujocoTracePresets() {
     return Object.keys(MUJOCO_TRACE_PRESETS);
   },
@@ -672,6 +601,10 @@ if (mujocoPlaybackTimeEl) {
 setMujocoPlaybackControlsVisible(false);
 syncMujocoPlaybackControls();
 
+void loadMujocoTraceFromUrl(MUJOCO_TRACE_PRESETS[DEFAULT_MUJOCO_TRACE_PRESET]).catch((err) => {
+  console.error('[MuJoCo overlay] Failed to load default preset', err);
+});
+
 /* ── Mobile toggle button wiring ── */
 if (mobileToggleEl) {
   mobileToggleEl.addEventListener('click', (e) => {
diff --git a/src/ui.js b/src/ui.js
index bf95ce7..3fe60c2 100644
--- a/src/ui.js
+++ b/src/ui.js
@@ -34,22 +34,9 @@ export function wireUI(state, hooks) {
     showAnnotations: state.showAnnotations,
     show3d: state.show3d,
     canShow3d: state.canShow3d,
-    presetName: '',
-    selectedPreset: '',
     selectedMujocoPreset: '',
   };
 
-  function presetOptions() {
-    const names = hooks.listPresets();
-    if (names.length === 0) return { none: '' };
-
-    const options = {};
-    for (const name of names) {
-      options[name] = name;
-    }
-    return options;
-  }
-
   function mujocoPresetOptions() {
     const names = hooks.listMujocoTracePresets?.() ?? [];
     if (names.length === 0) return { none: '' };
@@ -61,32 +48,8 @@ export function wireUI(state, hooks) {
     return options;
   }
 
-  let presetBinding = null;
   let mujocoPresetBinding = null;
 
-  function rebuildPresetList(preferredName = null) {
-    const options = presetOptions();
-    const optionValues = Object.values(options);
-    if (optionValues.length === 0) {
-      params.selectedPreset = '';
-    } else {
-      const next = preferredName && optionValues.includes(preferredName)
-        ? preferredName
-        : optionValues[0];
-      params.selectedPreset = next;
-    }
-
-    if (presetBinding) {
-      presetBinding.dispose();
-      presetBinding = null;
-    }
-
-    presetBinding = presetsFolder.addBinding(params, 'selectedPreset', {
-      label: 'Saved preset',
-      options,
-    });
-  }
-
   function rebuildMujocoPresetList(preferredName = null) {
     const options = mujocoPresetOptions();
     const optionValues = Object.values(options);
@@ -125,7 +88,6 @@ export function wireUI(state, hooks) {
   motionFolder.addButton({ title: 'Reset' }).on('click', () => {
     hooks.reset();
     syncFromState();
-    rebuildPresetList(params.selectedPreset);
     pane.refresh();
   });
 
@@ -184,24 +146,6 @@ export function wireUI(state, hooks) {
 
   const presetsFolder = pane.addFolder({ title: 'Presets', expanded: !isCompactViewport });
   presetsFolder.expanded = !isCompactViewport;
-  presetsFolder.addBinding(params, 'presetName', { label: 'Preset name' });
-  rebuildPresetList();
-  presetsFolder.addButton({ title: 'Save preset' }).on('click', () => {
-    const savedName = hooks.savePreset(params.presetName);
-    if (!savedName) return;
-    params.presetName = savedName;
-    rebuildPresetList(savedName);
-    pane.refresh();
-  });
-  presetsFolder.addButton({ title: 'Load selected preset' }).on('click', () => {
-    const target = params.selectedPreset;
-    if (!target) return;
-    const loaded = hooks.loadPreset(target);
-    if (!loaded) return;
-    syncFromState();
-    rebuildPresetList(target);
-    pane.refresh();
-  });
   rebuildMujocoPresetList();
   presetsFolder.addButton({ title: 'Load MuJoCo preset' }).on('click', async () => {
     const target = params.selectedMujocoPreset;