Way back when we were 12 or 13 years old, a group of us rode our bicycles out to the river about 6 miles from town for a day of fishing and goofing off in the river. Late that afternoon, we noticed a blue norther moving in.
For those not from Texas, a blue norther is a cold front that moves in during the summer or fall that literally looks like a massive blue-black wall of clouds and drops the air temperature 20 to 30 degrees in minutes. It is preceded with down-draft winds of 30 to 40 mph.
We packed up and started back asap as none of us wanted to be caught out in one. It is cold, wet and nasty to be caught in. As Boy Scouts, we tried to be prepared for anything and we all had our ponchos.The leading edge of the rain started to catch us, so we stopped and put on our ponchos. We had also learned with experimentation, that you could use a poncho like a sail on a bike.
I noticed that the wind was pushing on my poncho pretty good, so I spread it out and made a "sail". That wind got me up to 20 or 25 mph. The road, being a typical Texas Farm to Market road, had numerous 90 degree turns as the roads followed property lines. We had 8 or 9 of us strung out like a row of cattle heading home to the barn. We had to slow down for each turn, but then we could use the wind to get us back up to speed with very little effort and maintain decent speeds. With luck, we would make it home before we got TOO soaked.
Everything was going along "just swimmingly" until I came to another one of those 90 degree turns. I dropped my poncho edges, grabbed for the handle bars and hit the brakes. You know, those old fashioned Bendix brakes, that engaged the lock mechanism in the rear axle? NOT the fancy grip-style hand brakes on the handle bars, known back then as "ten-speed brakes". The kind of brakes that only work when you peddle backwards and the chain pushes backwards on the rear axle hub, engaging the brake. They work great, very much better than hand-grip brakes in wet weather. Only one thing - the chain has to be mounted to work. OOOPPPSSSS.
When I hit the brakes, the chain popped off and NOOO BRAKES!!!!! I could not slow down in the least. I flew off the road at 20+ mph, ending up rolling ass over tea kettle across a wet, plowed field with a bicycle rolling over me. No broken bones, just a lot of scrapes and bruises and a bicycle wheel that made a pretzel look straight. The guys stopped to see if I was OK and then took off for home. I started carrying my disabled bicycle home, still about 3 miles away, by now soaked through and through, covered in mud.
About 20 minutes later, a old pick-up rolled up. It was my best friend and his father. Michael's house was the first one the group came to, and as luck would have it, Michael's father happened to be home. His father was almost never home as he was one of 4 doctors in town, but for some reason, Dr. Leshikar had decided to come home for supper that evening rather than eating something from the hospital kitchen like he usually did. (Aside - the hospital was owned by the 4 doctors and one of the ways they made sure that the food was good was that they all ate at least 1 meal a day at the hospital.)
We loaded up my bike, went to Michael's house and then I got a check up from the doctor, followed by a lift home. No bill was ever received. That's just the way it was back then in a rural farming community.
Lesson learned? Well, DON'T slam on the brakes real hard if you haven't checked how loose the chain is.
That's how we found out that chains can "stretch" a little with use, becoming loose in the process. Tight enough to do the job, but capable of failing under stressful use.
I still prefer Bendix brakes to hand grip brakes. Just can't find them any more as every thing has gone to multi-gear systems.