SO I STOPPED MY CHAIN RING FROM COMING OFF MY 700 SERIES FOR ABOUT 75 CENTS!
I wanted to offer up an inexpensive fix for those of you who keep having your chain fly off your front chain ring. I ride 3 to 4 times a week and have about 800 miles on my 700 series it since I got it mid-summer, and I would suppose my front chain ring comes off once every two weeks or so. I always lose the chain in the easiest gear either up a hill or over a bump. After trying a substitute 46-tooth, shark-tooth-shaped replacement chain ring off of Amazon that promised to solve this problem (and caused my chain to fall off every 15 feet or so), I came up with this little gem and it's worked perfectly.
I bought a total of five, 13/16" (20.6 mm) washers with a 3/8" hole at my hardware store and, with some dexterity, inserted all 5 of them (1 washer per crank hole) on the RIGHT side of the chain ring between the chain ring and each crank arm. Because of the inexact fitment of the washer against the crank, it actually causes the crank ring to move INWARD (to the LEFT as you look from the back of the bike toward the front) a few millimeters and that minor change straightens the chain path enough on the easiest gear to prevent the chain from coming off the front. Believe me, I've TRIED to get the chain to jump off the front and it is now rock solid for me.
Below is a diagram for those that want to see the correct assembly order of the parts, but it would probably take you about 1/2 hour to try this out on your own bike (Just a warning, do NOT use threadlocker on the chain ring bolts, or it will be nearly impossible to remove them if you change your mind).
I hope this is helpful for someone...
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