Why is a broken or fallen chain so dangerous?
12-31-20, 01:15 AM
#26
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The wheel locking up is going to be an issue (which is not due to the chain, though, at least on a modern bike), or while out of the saddle and developing a lot of power where a sudden loss of resistance will likely make you lose balance.
Otherwise, the chain falling off is not a big deal, even at speed (with or without being clipped in).
Otherwise, the chain falling off is not a big deal, even at speed (with or without being clipped in).
12-31-20, 06:56 AM
#27
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The wheel locking up is going to be an issue (which is not due to the chain, though, at least on a modern bike), or while out of the saddle and developing a lot of power where a sudden loss of resistance will likely make you lose balance.
Otherwise, the chain falling off is not a big deal, even at speed (with or without being clipped in).
Otherwise, the chain falling off is not a big deal, even at speed (with or without being clipped in).
I/we use different quicklinks now, and change them more often. After her incident, I changed them out on all our bikes and now keep a log of when they were changed and how many times I've broken them for drive train cleaning or maintenance.
12-31-20, 07:36 AM
#28
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12-31-20, 08:14 AM
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His front wheel taco'd. Tells me the wheel might have turned taking him down. Believe me it is hard to steer when your chest is on the bars and knee on the pavement.
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12-31-20, 09:10 AM
#30
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I had a chain break while out of the saddle going up hill. No wheel lock up but I did go over the bars...not fun.
12-31-20, 09:30 AM
#31
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The way I look at it, when you're pedaling hard out of saddle, the pedals are supporting most of your weight. If the chain breaks, that support suddenly vanishes. It would be like climbing and having a foothold break loose. The sudden loss of balance causes the crash. How the crash actually unfolds depends on the precise details of how and when it broke.
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12-31-20, 09:32 AM
#32
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In a recent post, a gentleman described a bad accident that happened after his chain derailed. Apparently he was pedaling hard uphill when the chain came off the ring and he was hurled over the bars. Did this happen because all the force that he was applying to the drive train suddenly stop and it had to go somewhere else - in this case into forward motion to propel him over the bars?
I've crashed out of the saddle breaking chains and with unintended shifts off my big ring due to cross-chaining with worn teeth.
Conversely, I've been fine with the same thing happening seated on level ground.
12-31-20, 09:40 AM
#33
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I think I can answer this as I’m the gentleman you’re referring to. I believe your assessment is correct, I was leaning far over my bars and in fact pulling myself forward with each rotation of the pedals by pulling on the brake hoods for leverage. I had so much forward force in motion that I essentially catapulted myself over the bars and (I think?) I maintained my grip on the bars throughout the somersault thus pulling the bike on top of me once I hit the pavement.
But here’s where I’m still not sure what happened....... my chain is not broken!!!
But here’s where I’m still not sure what happened....... my chain is not broken!!!
The sudden forward rotation taking up the slack moving to a smaller ring can cause a crash when you're out of the saddle leaning into a hill and/or pulling on your handle bar.
Been there, done that. It took two crashes for me to realize what was going on and replace my big ring which was not noticeably worn or bent.
I was in the garage moments ago as I’ve been laid out on pain meds unable to move a great deal so didn’t see the bike until now. I will eventually take it to my LBS for repair and I suppose only then will I know what the heck happened. All I can describe is that it was like throwing a transmission into neutral while going full speed.
Last edited by Drew Eckhardt; 12-31-20 at 09:48 AM.
01-01-21, 07:05 AM
#34
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I had an unscheduled separation from the bike earlier this year due to the chain going into the back wheel - there's a post at https://www.bikeforums.net/classic-v...hain-tool.html detailing what happened. I was quite lucky, no great speed involved, and only minor bruising.
Tomm Willians - sorry to hear about your accident, best wishes for a quick recovery. Coincidentally mine was on a Peugeot as well!
Tomm Willians - sorry to hear about your accident, best wishes for a quick recovery. Coincidentally mine was on a Peugeot as well!
01-02-21, 03:54 PM
#35
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I broke a chain once. It was winter, and the chain was rusty. Of course it was rusty, what with salty slush being everwhere! Anyway, I was taking off from a stop and it broke right in the max power part of my stroke. Pedal immediately went to the bottom, foot slipped off the pedal, and I went down in a heap. I was right in front of an old lady standing at a bus stop. She was worried I'd hurt myself but I assured her I was OK, stuffed the chain in my pocket, lowered the seat, and draised the remaining mile to my office.
01-04-21, 12:38 PM
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also it can fall into the rear spokes and mess up a LOT of stuff
cogs
chain
spokes
derailleur hanger
derailleur
even the frame can be bent
cogs
chain
spokes
derailleur hanger
derailleur
even the frame can be bent
01-04-21, 04:52 PM
#37
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Ever since I got Di2, I pretty much never drop the chain anymore. And even when I have in the past, it's almost always been simply a matter of easy spinning and moving the front derailleur around a bit to hop it back onto the chainrings.
However, I had it for the first time on Di2 around mid-July last year, then again about a week later (both times, easy pedaling around 30km/h), resulting in *immediate* locking up of the rear wheel and this carnage:
That used to be your typical one-piece derailleur.
Thankfully, a RD-9000 I had in the parts pin uses the same jockey-wheel cage as the Di2, so I was able to salvage the rear derailleur.
However, I had it for the first time on Di2 around mid-July last year, then again about a week later (both times, easy pedaling around 30km/h), resulting in *immediate* locking up of the rear wheel and this carnage:
That used to be your typical one-piece derailleur.
Thankfully, a RD-9000 I had in the parts pin uses the same jockey-wheel cage as the Di2, so I was able to salvage the rear derailleur.
Last edited by notmyke; 01-04-21 at 04:57 PM.
