So last Sunday i did 26 miles and this is what i got mostly flat ride just 800 Ft of elevation gain so at that 52 miles would be 1880 i was a tad low on the first post.

CALORIES BURNED PER MINUTE

From: 9:45 AM
To: 12:25 PM
Calories Burned 940
AVG. METS 4.09
This is straight from my activity manager.
Here is the ride notice that Garmin is off too.
http://connect.garmin.com/activity/64864918