The Chrome Developer Toolbar lets you disable the cache altogether when it is open, but there is also a hidden option that lets you make one reload without using the cache.
For this to work, make sure the Developer Toolbar is open, then hold down the refresh button for the options to appear.
- For a regular reload of the page select the Normal Reload option.
- For a reload without using any cached resources, use Hard Reload.
- If you also want to completely empty the cache, to prevent the cached loading of even the resources that are loaded after the page load finishes use Empty Cache and Hard Reload.