chrys9989

but I don't understand how. Does anybody know how much power is needed to do that? Also, has anybody else had this happen with an Ultegra chain?

tollhousecookie

A typical (new) bike chain has the strength to lift 2,860 lbs. give or take.

Busta Quad

Every time I flex my quads.

Rutnick

I've broken one MTB and one Road chain. Probably defective.

I usually do what David Millar does in these situations:

https://www.youtube.com/watch?v=mIW1MAvyPD4

Bluechip

I've broken 2 chains in 25 years of riding. One was an old chain that was lacking in maintainance. It just wore out and broke. The other was a brand new chain. I think it was installed properly but must have had a defective link. It seperated on one side of the link. I was still able to soft pedal about 10 miles home. Breaking a good chain with your power is highly unlikely.

coasting 

maybe it wasn't put on right and had a weak join, in which case not much effort will break it

DaveSSS 

The term "broke" doesn't say much. There are many ways for a chain to fail, but the most common is simply an outer plate pulling off the end of a pin. That could be a manufacturing defect, but most likely, it's misinstallation or a shifting mishap that yanked the plate off the pin. Has nothing to do with power or more correctly, chain tension.

There have been cases of defective outer plate material (from wipperman) where the plates cracked around the pins.

chrys9989

I installed it properly, and how would shifting cause this, I don't get it.

ZIPP2001

I had my chain brake in the middle of my climb last Saturday. First time ever in the 30+ years of riding. It was all my falt because it was on my winter beater bike that doesn't get cleaned very often, and has been abused since 2001. Thank goodness I have always carried a chain tool in my bike bag, quick fix and off I went. It was the second time i've used it on the road, friend broke a chain about 14 years ago on a ride.

RichinPeoria

imho Shimano=broken and sooner or later you'll smash you gonads on the top tube when it happens.

chrys9989

The chain wasn't abused it had almost 150 miles on it, that's whats confusing me about this.

nebrider

Smashed my gonads twice as a result of a chain break.

coasting 

then we'll have to read another bustanut thread and cringe again

Bluechip

That would still considered to be a new chain. It was either installed improperly or was defective.

operator

There's two reasons why the chain broke:

1) Improper install
2) Worn out chain

Guess which one is most likely. I like how most people on this forum are smart enough to realize the difference between brake and break. Good job.

chrys9989

Ok, if I installed improperly then it would break at that pin, correct? Or is it possible that it would break at a pin several links away?

idcruiserman

Bad shifting can kill it as well.

operator

That's correct. Bad shifting can cause it to break, although I think extremely unlikely. Usually it just results in a twisted link. Mind you, most of the times i've seen this happen is on 7/8 speed chains. Maybe 9/10 just breaks. Someone fill in the blanks>?

DaveSSS 

Other than the case of defective material in the wipperman stainless chains, I've never seen a documented case of outer or inner plates breaking, but it could certainly happen. Most often, an other plate comes off the end of a pin.

Shimanao's joining pin is the most likely culprit, but when you have over 200 peened ends, the chances of one bad one increase. Older 7/8 speed chains were of the protruding pin design that had less chance of failing.

About shifting causing a failure - if you shift too late under a real heavy chain tension, the chain can get twisted and pull a plate off the pin. It might not occur at that moment, but later, so the cause is not obvious.

chrys9989

I'm thinking this might have happened cause I did some climbing on Thursday, but could it fail about 100 miles later? I was doing intervals today, but I don't really think I put out that much power.

Also, would anybody still use this chain, or am I out of $40.

D.J.M.

Mine broke after about 40km. With a loud boom. I was in a heavy gear, speeding up from standstill. It left me stranded in the middle of a very busy intersection.

I believe it happened due to a manufacturing defect.