Chain question

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Chain question

Postby jasnooks » Thu Dec 08, 2016 7:06 pm

Hey guys, i can't seem to find any definite info online, so i thought I'd ask here.
Forgive my ignorance, but I'm used to chains with master links.
Anyways, i have a decent chain tool (pic below) and I've split a 7 speed (3x7 bbb) chain (shown below).
So my question is, after i shorten the chain to the correct length, can i (using the chain breaker), just push that pin back in, and have a reliable link?
The machinist/mechanic in me says no. At least not without re-mushrooming the head after it's pressed thru. Or is that even reliable?
I'm guessing that a quick link (i think that's what their called for this type of chain) is the best bet, but i literally don't have $2 to spend right now.
So guys, what's the skinny on these skinny chains?

Image

Image
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Re: Chain question

Postby Tomcat65 » Thu Dec 08, 2016 7:40 pm

As long as you don't push the link all the way out, you can push it right back in.
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Re: Chain question

Postby jasnooks » Thu Dec 08, 2016 8:21 pm

Tomcat65 wrote:As long as you don't push the link all the way out, you can push it right back in.

The pic i posted is as far as i pushed the pin out. So after getting the chain the proper length i can just push it back in, and IT'LL HOLD? This is common practice? Obviously to the right depth, and without any binding.
I saw a guy rack his sack on the top tube last year, due to a chain break, that's the only reason I'm nervous, lol.
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Re: Chain question

Postby Tomcat65 » Thu Dec 08, 2016 8:45 pm

I've never had a break after pressing a pin back in - Not saying it's impossible - Most of the time though, I press back in, and then I have to give the chain a twist back and forth to loosen the link up.
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Re: Chain question

Postby frictionshift » Thu Dec 08, 2016 9:23 pm

I have squeezed them back in with vice grips, beat them back in with a hammer and punch, and put hundreds of miles on them afterwards.
But as Tomcat65 has already pointed out... It's not impossible for that pin to fail.

Then again, it isn't impossible for a factory installed pin to fail, or even a Master Link can fail for that matter.

My thought on those "master links", "second links", "missing links" ... are that they look different from your other links so it's easy to find your repair and give it a quick once over instead of inspecting the whole chain.
I'm the old man you see on the bike.
I love my 10 speed, but can't resist taking my 20 inch for a spin.
So I bought this cheap bike to use for donor parts, but find myself trying to build it back up now...
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Re: Chain question

Postby jasnooks » Thu Dec 08, 2016 9:49 pm

Ok, I'm convinced. I've read posts from both of you, and i respect your opinions.
And of course i know that any chain can fail. I just didn't want to do this blindly, and rack the old sack, just to have people say, bro you can't just push a pin back in without doing something or another..
Now that i know it's common practice, any mishaps are all on me.
This is my only means of transportation right now, and i greatly appreciate the help guys. Thank you both
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Re: Chain question

Postby dddd » Sun Jan 08, 2017 1:22 am

The thing with chains is that as chains get newer (more modern), and as they are narrower with more flush-riveted pins, the pin is designed so that the peening that gives each pin a bit of a head to it is supposed to shear off cleanly as the pin is pushed in through the side plate. This spares the hole in the sideplate from being enlarged, so that either a special pin can be pressed in tightly (Shimano chain) or that a connecting link can precisely replace one outer link.
Especially with newer chains that have the pins flush with the outside of the plate, either the peening shears off as a ring of metal left on the tool pin, or the peening gets turned inside-out to make a sharp-edged cup shape on the end of the pin. Then there are the Hyperglide 8s chains where pushing a pin out leaves a couple of metal shards that used to keep the side plate from popping off under stressful shifting.
I have fixed so many other rider's chains out on the trail over the years, usually they admit to having just pressed a chain together without a special pin or link.
These chains coming apart can do other things like snag on a derailer cage, tearing things up. And racking the sack is just one of the dangers, what if the bike veers into traffic or you fall to the wrong side of the trail?
There a lot of testimonials from shop mechanics who have learned this the hard way many years ago when customers returned to the shop with a broken chain, the same thing I learned back in the 90's when my own chain broke on the final steep pitch of Mount Diablo just before the end of the race.
So again, with very few exceptions, modern derailer chains are designed to be reliable under stress only when approved attachment methods are used. I buy KMC Missing Links in a card of six links for very little money. They do have a wider 7.3mm 8s version for Shimano 8s chain and a narrower one for SRAM and most KMC 8s chain. They also have 9s links that fit all 9s chains.
It's been almost 25 years now since the days when most chains could be reliably re-connected using just the tool and no special link or pin. Certain riding conditions might allow one to get away with a re-pressed modern chain pin, but I don't ride that gently and don't want to break any more chains.
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Re: Chain question

Postby jasnooks » Tue Jan 10, 2017 9:34 pm

dddd wrote:The thing with chains is that as chains get newer (more modern), and as they are narrower with more flush-riveted pins, the pin is designed so that the peening that gives each pin a bit of a head to it is supposed to shear off cleanly as the pin is pushed in through the side plate. This spares the hole in the sideplate from being enlarged, so that either a special pin can be pressed in tightly (Shimano chain) or that a connecting link can precisely replace one outer link.
Especially with newer chains that have the pins flush with the outside of the plate, either the peening shears off as a ring of metal left on the tool pin, or the peening gets turned inside-out to make a sharp-edged cup shape on the end of the pin. Then there are the Hyperglide 8s chains where pushing a pin out leaves a couple of metal shards that used to keep the side plate from popping off under stressful shifting.
I have fixed so many other rider's chains out on the trail over the years, usually they admit to having just pressed a chain together without a special pin or link.
These chains coming apart can do other things like snag on a derailer cage, tearing things up. And racking the sack is just one of the dangers, what if the bike veers into traffic or you fall to the wrong side of the trail?
There a lot of testimonials from shop mechanics who have learned this the hard way many years ago when customers returned to the shop with a broken chain, the same thing I learned back in the 90's when my own chain broke on the final steep pitch of Mount Diablo just before the end of the race.
So again, with very few exceptions, modern derailer chains are designed to be reliable under stress only when approved attachment methods are used. I buy KMC Missing Links in a card of six links for very little money. They do have a wider 7.3mm 8s version for Shimano 8s chain and a narrower one for SRAM and most KMC 8s chain. They also have 9s links that fit all 9s chains.
It's been almost 25 years now since the days when most chains could be reliably re-connected using just the tool and no special link or pin. Certain riding conditions might allow one to get away with a re-pressed modern chain pin, but I don't ride that gently and don't want to break any more chains.

Now you've got me questioning this..
I'm a pretty easy rider, but I do get off the seat and pump the pedals in higher gears on occasion, and at 215 lbs, I'm probably pushing the limits of the weak links, lol
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Re: Chain question

Postby dddd » Tue Jan 10, 2017 11:02 pm

What brand and model of chain is it? I could look at my chain remnants to see (with a magnifier) what happens to that particular model of chain's pin when it's pressed out. Like I said, most of today's chains lose the peening completely because it either breaks clean off or tears part way off until it's inside-out and forming a sort of cup out from the end of the pin!

I'd happily give you a used "missing link" if you lived in the neighborhood!

And if your gonna try riding on a re-pressed pin, just be prepared, so no hard off-saddle pedaling efforts or power shifting, ...and I would mark the affected link with sandpaper so you can find it and install a connecting link (or Shimano special pin) later when you acquire the needed part.
Last edited by dddd on Wed Jan 11, 2017 1:14 am, edited 1 time in total.
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Re: Chain question

Postby jasnooks » Tue Jan 10, 2017 11:48 pm

dddd wrote:What brand and model of chain is it? I could look at my chain remnants to see (with a magnifier) what happens to that particular model of chain's pin when it's pressed out. Like I said, most of today's chains lose the peening completely because it either breaks clean off or tears part way off until it's inside-out and forming a sort of cup out from the end of the pin!

I'd happily give you a used "missing link" if you lived in the neighborhood!

And if your gonna try riding on a re-pressed pin, just be prepared, so no hard off-saddle pedaling efforts or power shifting, ...and I would mark the affected link with sandpaper so you can find it and install a connecting link (or Shimano special pin) later when you acquire the needed part.


Thank you for the effort, but I've replaced the bike that this chain was on, and things are looking up financially. It's a spare bike now.
I'm not sure of the brand, but it didn't seem like the peen sheared off, but I didn't look at it with a magnifying glass (I'm old too). I rode it a few times since re joining it, with no ill effects, but I should probably invest in some "missing links" for future use
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