I have had 4 on my XR.. Almost forgot one.
First one Cruising way too fast on flat asphalt, I made a left on a green light and started heading up a small grade. I guess the motor couldnt handle any more and it nose dived.. I was going strait and maybe 20-21 MPH.. Sudden nose dive and wobble off. Maybe 38-40% battery remaining on Delirium.
The 2nd and 3rd to me felt no where near full speed (IMO But i havent reset my Top Speed and sometimes dont even start the App), I was going strait or mild carving and boom nose dive. One on a bike path one on flat Asphalt. Both over 40% battery 15 -18 MPH Delirium. Maybe I just really did ignore pushback and was going way to fast for the motor but I felt they were both at under 20mph and on a flat surface. I do like going fast... 50% chance User Error!
The 4th was me going way too fast again and hitting a bump in the concrete.. Instant speed wobble and nose dive.. This might have been recoverable with the flight fins and more confidence..
Since then I have installed the Flight Fins and Fangs 2.0.. I use the flight fins all the time to hop speed bumps small curbs and feel more stable off road.. I think they are a great Mod.
I have not had to use the Fangs yet.. I have been taking it easier and trying not to push it.. Slow downhill, Slow up hill, watch for bumps, Slow over bumps, Charge if under 35%, stay centered and no Hot dogging!!!
I do suggest helmet, wrist and/or gloves.. Elbow and knee protection wont hurt either.. High top Skate shoes... lol Have Fun!