The timeout for refreshes on Tableau Online cannot be changed - it is a global setting for all Tableau Online users. Have you considered using Tableau Bridge to update the extract locally on your computer and the publish the updated extract to Tableau Online?
Thank you for your reply. I've been looking this option as well but it seems it's for refreshing only data-sources right? In case I want to refresh the extract embedded in a workbook it would be possible somehow? I need this because later I want to download the workbook in order to open it with Tableau Reader.
Thank you again.