diff --git a/src/app/simulation.js b/src/app/simulation.js
index cf368c2..25697e4 100644
--- a/src/app/simulation.js
+++ b/src/app/simulation.js
@@ -39,8 +39,8 @@ export class Simulation extends EventEmitter {
    * @emits Simulation#pedal
    * @private
    */
-  onPedal() {
-    this._lastPedalTime = Date.now();
+  onPedal(timestamp) {
+    this._lastPedalTime = Number.isFinite(timestamp) ? timestamp : Date.now();
     /**
      * Pedal event.
      * @event Simulation#pedal
@@ -56,10 +56,12 @@ export class Simulation extends EventEmitter {
   schedulePedal() {
     if (this._interval === Infinity) return;
 
-    let timeSinceLast = Date.now() - this._lastPedalTime;
+    let now = Date.now();
+    let timeSinceLast = now - this._lastPedalTime;
     let timeUntilNext = Math.max(0, this._interval - timeSinceLast);
+    let nextPedalTime = now - timeSinceLast + this._interval;
     this._timeoutId = setTimeout(() => {
-      this.onPedal();
+      this.onPedal(nextPedalTime);
       this.schedulePedal();
     }, timeUntilNext);
   }
diff --git a/src/server/services/cycling-power/characteristics/cycling-power-measurement.js b/src/server/services/cycling-power/characteristics/cycling-power-measurement.js
index ae74d3b..3c4a9ac 100644
--- a/src/server/services/cycling-power/characteristics/cycling-power-measurement.js
+++ b/src/server/services/cycling-power/characteristics/cycling-power-measurement.js
@@ -1,7 +1,7 @@
 import {Characteristic, Descriptor} from '@abandonware/bleno';
 
 const FLAG_HASCRANKDATA = (1<<5);
-const CRANK_TIMESTAMP_SCALE = 1000 / 1024; // timestamp resolution is 1/1024 sec
+const CRANK_TIMESTAMP_SCALE = 1024 / 1000; // timestamp resolution is 1/1024 sec
 
 /**
  * Bluetooth LE GATT Cycling Power Measurement Characteristic implementation.
@@ -41,7 +41,7 @@ export class CyclingPowerMeasurementCharacteristic extends Characteristic {
     // include crank data if provided
     if (crank) {
       const revolutions16bit = crank.revolutions & 0xffff;
-      const timestamp16bit = Math.floor(crank.timestamp * CRANK_TIMESTAMP_SCALE) & 0xffff;
+      const timestamp16bit = Math.round(crank.timestamp * CRANK_TIMESTAMP_SCALE) & 0xffff;
       value.writeUInt16LE(revolutions16bit, 4);
       value.writeUInt16LE(timestamp16bit, 6);
       flags |= FLAG_HASCRANKDATA;