Ive learned in my 2 years of riding these thing if you gas it while your in a corner your chain popping off %age goes way, so I've learned to coast while dipping into a corner and gas on straight aways!! Haven't dropped a chain since. I think there's something to do with the way the rag joint pulls on the spokes makes the front sprocket uneven with the rear sprocket.
I had one drop on me and it just locked up my rear tire I suppose if I had only one hand on the handle bars it could have sent me flying." Since then I never take my hands off while riding NEVER!!"
To avoid this I recommend getting rid of the rag joint rear sprocket set up & get one of those aluminum axle adaptors " Wish I could afford one" I've been through so many rear rims with the rag joint it isn't funny couple that with that adapter /chain tensioner you built and your worries should be gone . However rest assured... a new worry WILL immediately appear in the fixed chains place
As far as the tensioner destroying your rear tire. How? Did it pull into the spokes ? If it did. What I did is...I wrapped a piece of rubber inner tube around the chainstay then mounted the hardware a step further you could take a very small drill bit and drill a hole half way through it all then I just snapped the drill bit off inside... "It was actually an accident it broke because i let the drill go off center" I just make it sound like I wanted to do it, so I don't look like the idiot I really am ! Either way it has kept the tensioner from moving for over a year now!... just make sure you line it up before drilling ...
I've also found out the rubber alone can be sufficient enough to keep it from moving I push my tensioner way down as close to the sprocket as I can get it I do this by leaving the poly bearing loose while tapping the entire finger tight tensioner towards the rear sprocket "rubber and all" It slid down nicely, till it is where I need it most of the times the poly bearing the chain rides on is all the way down on the adjustment slot. At that point I tighten it up and off ya go!
P.S. Be safe ride smart & always ride as if the cars do not see you because most of the time they do not!!! & they certainly do not expect us to come up as quickly as we do. this is all stuff I've learned the hard way ..so you don't have to!!!