Google FIT no data synch from mobile to web

So, I'm using a S3 mobile. Previously I was using Google Tracks. Now they say they will terminate Tracks, advising to switch to Google Fit. I did it, I installed google Fit on my mobile and used it to keep trace of my (lazy) running activity. I supposed to find same data on the web "google Fit" page, but nothing happens. I mean, on the web I can't find any data about my activity, data that are available on my mobile. Be sure that my web google account is the same as my mobile one.
When I was using Runtastic everything was working smoothly. That's why I think to swtich back to Runtastic.
Both on the web page and on the mobil app I didn't find any hint about synchronisation, any menu item, nothing.
Any hint about it?