Tired of frequent chain's derailments, yesterday i built a simple remedy.
I started from a 20mm aluminium bar, cutted two 40mm lenght pieces and drillead a 6mm hole on both to pass the bolt.
Then i built a little fold on the upper corner, to lock it on the tensioner and prevent possible revolution around the bolt ...
This is the result:
Now i can freely pedal also in the bumpy ride, without the chain jump out ...
Alex Bromo