GTM, analytics.js and custom dimensions

Question

I have a website with a front-end I'm not allowed to touch. It has both Google Analytic's analytics.js and Google Tag Manager separately installed. Google Analytics is not installed via Google Tag Manager. I have admin access to both accounts. I'm trying to track custom dimensions in GA via GTM (outbound links, scroll depth, etc, etc, etc). I know how to do this when you install GA via GTM, but not otherwise. (I'm also trying to not mess up analytics numbers via installing GA twice by adding it again in GTM.) Any help would be appreciated, thanks.

Answer 1

Because you have anlaytics.js on the page already, in GTM you won't need the pageview related GA tags. Instead, you would focus on the tags for GA event tracking and you can include the custom dimensions in those tags. This way you won't get double pageviews.