Happens some time.

How quickly were you able to hit stop on your garmin?

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//Noob triathlete//bike commuter//ex-swimmer//slower than you

I had a chain break earlier this year. Sometimes, stuff just breaks.

Did your chain break, or did it just derail and jam your back wheel?

Did your chain fall off and go into the rear spokes? Or, did you shift into the small front ring and lose the chain into the crankset? How exactly did you crash?

Could be you didn't have the chain installed correctly ( i.e., the right amount of links removed) and was too loose.

Sorry about your wreck!

good one ha

Did not break just jammed up. Chain installed correctly. It stopped me and there was no choice but to go down.

The possible causes in no particular order are:

• One-off fluke event
• Worn derailleur
• Mis-adjusted derailleur

How old is the bike (front derailleur, rear derailleur, chain)? How long has it been since anyone adjusted the front or read derailleur?

Sorry about the fall but you got to get faster. Centrifugal forces keep you upright when going straight.


I dumped it during a 70.3 at mile 15 in a roundabout. 920XT went from 25.2mph to 0mph without hitting the button. ;0)

Add dirty freehub to that list

I'm not sure I understand excatly what happend. Did the chain/ rear derailleur get sucked into in the rear wheel? If the chain breaks or falls off the front chain rings you should be able to simply stop pedalling and coast safely to a stop. I have broken and dropped my chain numerous times and had a front derailleur snap off under hard accelartion without ever going down. I have a chain keeper now which also helps.

Sorry about your crash, the next week is not going to be fun.

My question was about how you got 'jammed up'. Did the chain get sucked into the inside of the front chainrings, or did it pop all the way off and somehow get caught into your rear spokes above the rear chainstay? Or, did your rear derailleur go into your spokes?

Since you were asking us how this happened, this detail is very important.

Thanks-

The chain came off and prevented the pedal from turning. I do not know exactly how or why. The bike got picked up and the chain moved around after so I cannot see how it ended up. It did not break. It seems like it went over the right side of the gear because the bike is now in my garage with the chain still off in that position on the right/outside of the gear.

How quickly were you able to hit stop on your garmin?
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Rookie problems. Advanced users set auto-pause.

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Take a short break from ST and read my blog:
http://tri-banter.blogspot.com/

My rear mech on my mountain bike has a clutch mechanism to keep tension on the chain. The old groupset I had I would drop a chain now and again but since upgrading I have no problems. Is there any reason why you couldn't have this setup on a road bike? I believe they are indexed the same. I've wondered that before such as when you see all the chain slap on the classic races like Paris-Roubaix over the cobbles.

Clutch R der causes extra drivetrain drag.

It's totally worth it for a mtb, and overkill 99% of the time for a road bike.

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float , hammer , and jog

That makes sense. Cheers

My guess is misadjusted rear derailleur.

The chain coming off on the front will prevent you from pedalling, but won't stop the bike. The only way the chain comes off the rear derailleur is musadjustment or something breaking.

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Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

Everything has a reason.

Where on your bike did the chain jam? Between the chainstay and crankset?

1X set up? or 2x11 (2x10) set up?

What type and brand of FD, if any?

Any chain catcher installed? If yes, what type?

What drivetrain?

How many miles on drivetrain only?

What type and brand of chain?

How many miles on chain only?

What kind of connection? Quick link, shimano pin, other?

Who installed the chain?

How did they install the chain?

If you can answer these, I think it is possible to know for sure why the chain locked up.

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I'd add - which gear of the rear cassette would you of been in at the time? It sounds like you weren't changing gear at the time but maybe confirm that?

The rear wheel locked up, and you went into a slide, right?

Here are a bunch more diagnostics questions to help everyone figure out what might have happened. When it occurred...

• Were you pedaling hard or average?
• Were you on the seat or standing?
• Did it happen when you shifted or just pedaling along?
• Did you shift the front or read derailleur?
• Did you shift to a harder or easier gear?
• If rear shift, were you on the hardest gear, middle, or easiest gear?
• If rear shift, did you shift one gear or multiple gears?
• Is there any evidence of spoke damage by the largest rear cog?
• Does your rear derailleur look straight and aligned vertically?
• See earlier questions about age of equipment and most recent maintenance.

I had something like this happen, It was my rear skewer. It had allowed my wheel to moved when under pressure. It took awhile to figure this out. Like you my bike had been moved and wheel had been removed. It happened on another ride to a lesser extent and i found the problem.

It just sounds like chain slap caused by just bad luck/combo of hitting a bump and having enough slack in the chain, perhaps from being in an easy gear, to allow the rd to flex forward and the chain to temporarily jam against something temporarily. It happens, usually doesn't cause a wreck.
Only suggestion to prevent future occurrences - make sure everything is tuned up properly, including rd limit screws, and make sure the chain is correct length. Take out a link or two if it is a bit on the long side to help prevent chain slap.

Bent hangers can cause a chain to go in to the spokes too.

your guess? or evidence based?

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Dan Empfield
aka Slowman