# Powerlink failure



## ki5ka (Dec 17, 2006)

Powerlink failure
Sram 9 spd powerlink on a Sram 9 spd chain. 

I recently removed the chain (drive chain, not timing) for maintenance, but we have ridden it since and considering that the chain will not seat if the link hasn't locked into place I don't think that is the cause. 

We ARE having issues dropping the chain off the small ring and jamming it between the BB and crank. Seems likely this caused the failure, but an examination of the half of the link we recovered shows no failure or deformation leading me to ponder other possibilities. Of course, the other half might be trashed and I wouldn't know...

I have the impression that Powerlinks have a stellar reputation. Am I correct? Anyone else have a failure story? Kinda seems like a new poll is brewing


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## Okayfine (Sep 7, 2010)

Have been running bottom-rung SRAM 951 chains for over 7 years and have never had a PL failure. Have broken drive chains two or three times and finished the rides with a second PL. Also have two PLs in our sync chain at all times.

There can be damage done to the chain in the BB/crank cavity via a ring bolt coming around. Some work with the Low limit screw on the FD should cure that for the most part. We have that occur rarely, and usually we can catch it and backpedal to reseat the chain.


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## ki5ka (Dec 17, 2006)

Okayfine said:


> Have been running bottom-rung SRAM 951 chains for over 7 years and have never had a PL failure.


Your experinece matches ours. This is our first PL failure, and have similarly had chain failures on other links. Failure to keep the chain out of the BB is the cause I expect to confirm.

Thanks for the input.
k


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## PMK (Oct 12, 2004)

Not Jinxing us...

PK


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## mhopton (Nov 27, 2005)

Timely thread. We just blew apart a sram 9sp drive chain last weekend. On a very rough section of trail coming out of a roller at speed and hitting some big roots, I made a bad shift and the chain sounded like a gun shot as it exploded at the powerlink. It took about 2 min to fix with a new conex quik link.

That's the first I've ever broken a quick link. I didn't think twice about it and just assumed the torque and stress of the tandem was too much.


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## XC Mike (Sep 26, 2004)

Just picked up a spare today never know...


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## Okayfine (Sep 7, 2010)

Whenever I change chains I keep the old PL and put it in my pack. If you have a spare, you're guaranteed not to need it on the trail, but someone else might. I've given two away.


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## XC Mike (Sep 26, 2004)

Talking about chains how many miles should I get out of them before replacing them??


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## Okayfine (Sep 7, 2010)

Impossible to specify. 6-months to years, depending. 

Best practice is to check with a ruler over 12", pin to pin, and replace when necessary. The more wear you run, the more you wear your chain rings and cassette, and only chains are cheap. I generally change the drive chain 1-2 times a year, depending on how much we are riding, and the sync chain every 2-3 years. But we're a heavier team and have a lot of hills. Lighter teams running the flats (our Burley road tandem, for example) could extend that kind of service for much, much longer.


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## ki5ka (Dec 17, 2006)

OK, had another Powerlink fall off. I know that on a tandem, shifting is a whole new world... making this a post for here, rather than elsewhere. I'm going to do a poll.. but I don't feel like doing it now, so just watch out for it, OK?


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## ki5ka (Dec 17, 2006)

I don't even know what to ask. Did your powerlink fail? That wouldn't be very useful information. Any ideas?


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## Okayfine (Sep 7, 2010)

ki5ka said:


> OK, had another Powerlink fall off. I know that on a tandem, shifting is a whole new world...


I've ham-fisted enough shifts over the years, still have not had an issue with the PL.


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## reamer41 (Mar 26, 2007)

Been using the power links for years. 12, maybe longer. Never had a problem. 
Well I've had some problems, but not involving a powerlink.


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## PMK (Oct 12, 2004)

Poll or not, without jinxing us, we have had excellent results with high SRAM chains and PL.

We have witnessed some snapped chains, and other driveline issues. As you mentioned, the tandem is a bit different when shifting. Watching others, they would not anticipate a climb, or would mash the pedals to get over stuff and boom, broken chain. Others seem to prefer running dry lubes and I suspect they simply wear out the chain and it fails.

Higher rpm, anticipate the upcoming feature, and ensure the chain is lubricated. Outside of that, Rohloff that does not bend the chain and will shift while coasting and not pedaling.

Also, on a full suspension machine, it is imperative that the cables can flex enough to prevent ghost shifts. If in doubt run a full outer housing.

PK


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## ki5ka (Dec 17, 2006)

It's weird, they haven't broken, just fallen off. Usually during a bad shift under high load. Thought it had to do with the chain getting damaged from when it dropped into the bb, but have since fixed that problem and still had it happen. Saw something about installing a Powerlink "backwards" but I don't think the 9 speed is directional, as far as I can tell. No arrows on mine.


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## DHMASTER (Oct 12, 2010)

"I recently removed the chain (drive chain, not timing) for maintenance, but we have ridden it since and considering that the chain will not seat if the link hasn't locked into place I don't think that is the cause. " 
The only time that I've see this type of failure is when the links are not fully seated before shifting under load. Unseated links can pass through without binding, pedaling or on a stand. I have found that all of my current powerlinks need to be fully loaded full weight to make them pop/ seat into their final resting place. If you did not put full standing weight on that link (with intent of seating it) prior to the mishap, I propose that this could be the issue.


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## ki5ka (Dec 17, 2006)

DHMASTER said:


> If you did not put full standing weight on that link (with intent of seating it) prior to the mishap, I propose that this could be the issue.


DH, that makes good sense. Have you had this happen; a Powerlink fall off?

Our regular ride has many demanding climbs which we routinely stand on. I can't imagine that we didn't do so many times before this PL "fell off". Of course, I could be wrong, that is the rub, isn't it?!  I also have looked pretty carefully at the link before riding, since we HAVE had issues, and it LOOKED like it was fully seated.


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## jokaankit (May 4, 2014)

Had this happen to me today, on a pc951. One of the pins on the powerlink was ejected. I ended up losing it and walking back. Not that I could have fixed it even if I had the tools and no spare powerlink. The days before I had lots of shifting problems and chain drops. Just before the incident I was in small gears torquing for speed on some smooth sections.

Not sure If I should just buy a new chain, or look to get some spare powerlinks. I have less the 500 miles on the chain/bike.


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## ki5ka (Dec 17, 2006)

It seems there is always some time beforehand where things get wonky. I'm getting to the point where I know it's going to happen before it does. I think that means it has happened a lot!


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## switchbacktrog (May 10, 2013)

jokaankit said:


> Not sure If I should just buy a new chain, or look to get some spare powerlinks. I have less the 500 miles on the chain/bike.


I've never managed to get much more than 350 miles from a tandem primary chain before it's beyond the 0.75% stretch limit. I always carry spare powerlinks though, and only ever used them on someone else's bike.


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## Okayfine (Sep 7, 2010)

switchbacktrog said:


> I always carry spare powerlinks though, and only ever used them on someone else's bike.


Same.

When I put a new chain on the tandem, I keep the PLs and put them in my pack. I have half a dozen or more.

Also keep in mind that SRAM chain quality can vary (as can any manufacturer). There was a spat of chains a few years back that regularly broke. Then a new batch came out and they were as tough as ever. If your chains/PLs that you're having trouble with were ordered at the same time (I buy in batches, maybe others do as well) then that could be another reason. The PL, in particular, isn't prone to problems IME.


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## reamer41 (Mar 26, 2007)

It just occurred to me that I've been using KNC chains and their power links for a few years. 
Before that used SRAM for many years. No troubles with either


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## Okayfine (Sep 7, 2010)

Actually had a PL fail this weekend. Chain and PL are <6 months old. PL broke at the open ends of the links. Quicker to break the chain as necessary to substitute a used PL from my pack, finished 20 more miles without issue.

First PL failure we've recorded. New chain going on this week for next weekend's riding.


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