Take the 2-minute tour ×
Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. It's 100% free, no registration required.

According to: http://www.sram.com/sram/road/technologies/powerlock

"SRAM chain engineers developed PowerLock as a tool free, sure and consistent way to connect our 10 speed chains. While PL does not require special tools for install, the especially tight tolerances of 10 Speed drive trains mandated that each PowerLock is good for a one-time application only."

According to: http://www.competitivecyclist.com/sram-pc-1051-chain

The SRAM PC-1051 Chain is compatible with both SRAM and Shimano 10-speed drivetrains. Please note that while the PowerLock installation can be done tool-free, it's recommended to be used only once due to the extremely close tolerances required by the narrow 10-speed design. So if you must break your chain for maintenance reasons, a new 10-speed PowerLock link will be required to reassemble it.

Two questions:

  • Why is this the case?
  • Have people hear observed or seen tests about what happens if you re-use?

I use the Park Tool Master Link Pliers to remove master links. I have a hard time believing that doing it that way stresses it significantly.

Related, from http://www.bikeradar.com/us/mtb/gear/article/trail-tech-mastering-master-links-36757/:

"According to SRAM, the ridge that joins the two plates of the PowerLock together can be damaged when unlocking it, increasing the risk of failure if reused. So yes, if you choose to reuse a PowerLock there is an increased likelihood of if failing, according to SRAM."

I know a number of professional and team mechanics who routinely reuse PowerLocks on their own bikes, but replace them with a new link when dealing with a customer or athlete, so it’s a bit of “do as I say, not as I do.”

share|improve this question
1  
I've reused the one on my road bike a number of times (3??) with no ill effects that I've noticed. Although I don't recommend this as the manual specifically says not to. I'm always slightly aware in the back of my mind that it could pop open at any time, it's one of the reasons that my SRAM mountain bike has a 9 speed drive train. Time for a new chain on my road bike anyway, I will probably order a handful of links too. –  alex Sep 27 '13 at 3:06
1  
The link for a 10-speed is pretty light, and I suspect that there simply a (legitimate) concern that the piece will become worn or deformed with reuse, especially if not carefully disassembled. I wouldn't be too reluctant to reuse the link in an emergency, but would attempt not to in normal maintenance. –  Daniel R Hicks Sep 27 '13 at 10:53
    
Cynic in me feels its a good way to sell lots of parts that cost a few cents to make but cost you a few $. The almighty "Safety Card" trumps everything. Do you really think your fingers are strong enough can damage a part designed to handle the forces a bike chain is subjected to? However, in case I am wrong, I do use new ones, but would not hesitate to reuse one in an emergency.... –  mattnz Sep 28 '13 at 3:45
add comment

4 Answers

up vote 1 down vote accepted

It's not so much that reusing the link increases the chance that the pins or plates that the Powerlock is made up of will fail, but rather that it increases the chance that the link will come apart the same way it was put together. Each time you remove that link it wears down the "ridge" that snaps the pins in place on their opposing plates. This increases the chance that the link can undo itself in unusual circumstances. It may also slightly increase the chance of the link failing in the case of shifting under heavy load, which should be avoided anyway.

SRAMs 9 speed quick links were notorious for coming apart on the trail as they are reusable- some of this had to do with improper removal which damaged the relief that held the pins in place. It's probably easier for the company to just say "don't do it" than to say "do it this way" and folks don't adhere to the manufacturer's recommendations, leading to failures.

TL;DR version- if you only remove the link on occasion, its good for the life of the chain. Don't reuse an old quick link on a new chain.

share|improve this answer
    
Thanks for answering the "why" part of my question. –  David James Oct 14 '13 at 2:51
    
I just popped open and SRAM 10 speed PowerLock as I was swapping some components. The PowerLock still fit together quite tightly, so tightly in fact I couldn't get it to lock by hand. I suspect you can do it a few times before worrying about it randomly coming apart. –  Rider_X Oct 16 '13 at 5:42
add comment

It seems that if you are running a SRAM Force or Red drivetrain, the cost of a $4.00 link is a drop in the bucket. If you are concerned about it, just get a new one.

The worry about your chain's integrity is probably not worth the price of a Red Bull...

share|improve this answer
    
This is a comment -- and may be good advice -- but it doesn't fit as an answer. The Q&A format works better when the community uses it carefully. –  David James Oct 14 '13 at 2:54
add comment

I would follow SRAMs guidance on this one. Note that there are other quick links available that work with all chains (and can be reused). KMC's missing links (depending on the model) are reusable: http://www.kmcchain.eu/?en/products/connectors/missing_links/

share|improve this answer
    
This makes sense as a comment, but not as an answer. –  David James Oct 14 '13 at 2:52
    
A caveat with this - KMC missing links only really work with KMC chains on 10 speed. Theres a bit of play with Shimano (though they market it with Shimano as acceptable) and way too much play when used with an SRAM chain. –  Batman Dec 6 '13 at 16:12
add comment

I had my master link fail on the weekend. It had been reused 5 times, and separated itself from the rest of the chain at the base of a 4k climb. Will be replacing it each time from now on. I was lucky that the chain didn't go through the spokes, damage the bike or go under the wheel and cause a pile up.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.