diff --git a/src/lib/slider/slider.ts b/src/lib/slider/slider.ts
index ef3c1e937138..7f7729218c87 100644
--- a/src/lib/slider/slider.ts
+++ b/src/lib/slider/slider.ts
@@ -182,6 +182,7 @@ export class MdSlider implements AfterContentInit, ControlValueAccessor {
 
     this.isActive = true;
     this.isSliding = false;
+    this._sliderDimensions = this._renderer.getSliderDimensions();
     this._renderer.addFocus();
     this.updateValueFromPosition(event.clientX);
     this.snapThumbToValue();
@@ -207,6 +208,7 @@ export class MdSlider implements AfterContentInit, ControlValueAccessor {
     event.preventDefault();
     this.isSliding = true;
     this.isActive = true;
+    this._sliderDimensions = this._renderer.getSliderDimensions();
     this._renderer.addFocus();
     this.updateValueFromPosition(event.center.x);
   }