I have the bicycle running deer system.
I took the wife's bike, she was none too happy but wasn't using it anyway
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Separated the front wheel from the frame and welded brackets on the fork and chassis to mount to trees. Strung cable between the trees about 70 yards apart (same trees). Put the deer attached with all thread rods through rear and neck on the cable and hooked the pull rope around bicycle wheels to front and back of deer.
Made a special bracket to attach 12v motor to drive of bicycle and then a weatherproof remote switch and deep cycle batteries.
Speed can be adjusted by using different sprockets on the 10 speed bike I used.
Everyone seems to enjoy it....never worried too much about back stop other than being safe! but then again, I sell arrows
BigJIm