Today I did a ride on my 2012 DS that I had done on my 2010 DS of 46 miles. It was a beautiful southern CA desert day with light wind and temp in the mid-seventies. An open desert highway with no traffic and some ups and downs with two steep short grades each direction. I held my speed to 40 - 45 mph and rode to a cafe where I had ridden my 2010 DS and could plug it in.
Last year the 2010 was almost "out of gas" when I arrived and I waited 2 1/2 hours to be sure I had enough charge to make it back to my desert cabin. This time, after 23 miles I arrived with one bar above 1/2 on my gauge. Since this was my first "long" ride I plugged it in, just to be sure, since I didn't have any "rescue" available.
I was there for 50 minutes and I gained two bars above the one bar above 1/2. Same speed on the return trip except for one quick acceleration to 75 mph (good thing I had a good grip when I rolled the throttle on at a cruising speed of 45, it felt like I would go off the back).
When I got back, at 46 miles total, I still had four bars on the gauge, so maybe, if it's linear, I would have returned with two bars if I hadn't plugged it in at the cafe. I'm sure the rapid acceleration to 75mph sucked some significant power.
I felt the motor case when I got back and it was only warm, not hot by any judgment.
BTW - Cruising at 40 - 45 on a beautiful southern CA desert day was very enjoyable, but of course I had a tendency to let the speed creep up until I would notice and bring it back down.
This was with the stock tires.
Take it for what it's worth,
Trikester