On Monday, April 29, 2019 at 2:26:15 AM UTC-4, wrote:
On Saturday, April 27, 2019 at 9:12:38 AM UTC-5, Joerg wrote:

Chains usually do not snap without some serious lack of maintenance or
running them way past prime. Never heard of a driveshaft break except
once on a heavy vehicle (bus). Belts usually snap out of the blue.


I've been on two rides where bicycle chains broke. One was mine. Hit a small bump/curb on the trail when crossing a street and the chain jumped off its cogs/pulleys/rings and got lodged somehow and it broke when I started pedaling again. Used the chain tool to remove the broken link and put in one of the quick links to reconnect everything. Other time was on a group ride and one of the riders broke his chain. I used my chain tool to remove the broken link and gave him my quick link to put everything back together.. Took a few minutes on the side of the road to get everything working again. But it was all resolved successfully. So people who think chains don't break on rides are living in some make believe fantasy land.

I broke one on a mountain bike ride when I missed a sudden shift to the granny.
My wife cracked one quick link a couple years ago. I remember one club ride
where someone broke a chain.

So I can't say chains don't break. But I can say that those are the only
incidents I remember since 1972, when I started adult riding. That includes
many hundreds of club rides with anywhere from three to a couple dozen people.
That includes my decades of running, then sagging a fair-sized century ride..
(We had up to 600 riders.)

So I'm talking about 3 chains in hundreds of thousands of rider miles, I'm sure. It's not a common event.

- Frank Krygowski