miamijim

There's a little truth to what he says.

If a chain and cassette/freewheel are gunked up the gunk/dirt/grease/grime/oil takes up a tick small amount of space between the link/rollers/pins. Think of all that stuff as being like a 'shim' Remove all that and something has to take up that 'space'. Chain 'stretch' is what does.

Try it sometime. Measure a gunked up chain, clean it and measure again. That being said, you'd need an already stretched out and gunked chain for it to make a difference.

T-Mar

Several years ago, I had a Greenpeace volunteer come to my house canvassing for donations. I politely refused, explaining that we had already donated an allocated amount of our discretionary income to our preferred charities. I attempted to close the door but she held it open and became very aggressive, trying to lay an environmental guilt trip on me. Noticing a strange automobile sitting at the curb, I inquired whether it was hers and she said "Yes, what's that got to do with anything?" I was getting PO'd and replied,"Well, I guess I'm doing a lot more for the environment than you are because I don't own a car or even have driver's license. I walk or bicycle everywhere. If you truly cared about the environment as much as you say you do, you'd get rid of that monstrosity and do the same!" Her jaw dropped faster than I could slam the door in her face.

dddd

I am surprised to find such detailed photos of the chain's inner wear surfaces, I didn't even consider it worthwhile to search for them!

But I don't consider it likely worthwhile to reverse the chain even once during it's service life on account of roller-to-bush wear.
This because once the wear occurs to the more-worn side of the sideplate bushes, it doesn't get put back when the chain is reversed. The lower-wear side gets moved to the higher-wear position, but the wear still contributes to roller freeplay in the loaded direction.
And, speaking of roller free-play, this doesn't contribute to any increase in the chain's pitch, so would not be expected to affect sprocket wear or even the ability to mate with more- or less-worn sprockets. It's kind of irrelevent then, no?

Then there is the severely-worn state of the pictured chain links! While it would in theory be a good idea to reverse a chain before (as pictured) the bush surfaces were failing asymmetrically, I believe that this chain's wear status is of the order of perhaps 2% or more, which would be about 4X of the recommended replacement point! I can't recall seeing a chain this worn on any modern bike given even a minimum of economy-class servicing, and I've studied many chain link parts over the years.

It's likely that the pin-to-bush surfaces (independent of the rollers!) have their own wear asymmetry of a different sort, namely that the wear will tend to occur slightly off of the purely length-wise axis, and which would mean that inside-outing (not reversing) the chain loop might somewhat actually benefit the chain's effective pitch as it "bends" around the finite radii of the sprockets. I'm not able to measure this however, since all of my chain measuring tools/techniques pull the chain in straight tension as it is measured.

So, for those who are perhaps already removing their chain for some reason during it's service life, perhaps some benefit to the chain's effective pitch (and thus service life) might be realized by flipping the chain's loop inside-out! But this of course excludes all of the newer, so-called "directional" chains (which aren't so much directional as asymmetric, semantics noted earlier by CliffordK in one of this thread's first replies).
And further, per jackbombay's datapoint, and to the extent that inside-outing the chain loop benefits (reduces) the chain's effective pitch, I suppose that in the case of a severely-worn chain that this might actually cause slipping on the "more-worn" (than the flipped chain's pitch) sprockets that the worn chain was wedded to!

madpogue 

That LBS employee was engaged in what I often hear of as "man-splaining". His mention of the directional chain may have just been his modern bike bias showing. I've had FLAPS or dealership employees offer to sell me the belt tensioner when I'm buying v-belts for my '85 Ford; I try to answer as politely as possible.

I liken LBS and car dealership employees to "pediatricians", trained and accustomed to dealing with 1 to 5 year olds. Technologies that we take for granted, that were once "conventional", are "exotic" to them. C&V-ers, and those who keep "older" motor vehicles, should be on the lookout for "gerontologists", the people who work in old-school self-managed shops, who know where every obscure tool and every squirreled-away part is located.

The "rule of thumb" I recall from BITD, to measure chain elongation -- remember that the span between two pins is (well, should be) exactly 1/2 inch. So a "full link" (outer + inner) is 1 inch. So measure 12 full links, center-of-pin to center-of-pin. If the pin center of that last link is more than 1/16 inch beyond the 12 inches, the chain is shot. If you work on a lot of bikes, this - https://www.parktool.com/product/chain-checker-cc-2 - comes in handy. A little spendy brand new; I think I got mine at "the swap" a few years ago for $10. It's paid for itself in spades.

I parlayed a similar experience into a few thousand 20-ish years ago. Attended an informational gathering at the local furrier, handing out info about the fur industry to customers as they entered. Totally friendly/cordial. Happened to be across the street from a car dealer, that happened to have a 5-speed Saturn wagon on the used lot (unusual sight) that I happened to be in the market for. Went in the next week for a test drive, decided to buy the car, and as the sales guy went off to do some paperwork, I overhear another salesman talking about "those radical protesters last Friday, probably wearing leather shoes, blah blah blah". I stepped up and asked how he knew what they were wearing. Told him I was there, wearing hemp shoes, and that's when I saw the car that I'm now thinking of NOT buying. The other guy present was the manager of the dealer. Without my asking, he knocked two grand off the price, added an extended warranty (which I ended up using, twice), and gave me a grand more in trade than I was going to sell my old car for. Got a feeling that salesman didn't even get the set of steak knives that month...

And yes, I was "acting" offended; takes a lot more than a blowhard uninformed car salesman to offend me.

riva

Google "sawdust transmission used car." Fouled lube can make a difference in some cases. Not gonna pick sides for this particular case, all I'm saying is it CAN make a difference. Maybe the shop guy is a man-splainer OR... maybe was just trying to make some interesting conversation.

Also can I just say, chain is awesome. Its such a wonderful way to transmit power. Driveshafts gears hydro pumps and rubber belts not nearly as good a way. A good chain hardly will ever fail or need fussing over. And inexpensive to replace most times. I love chain.

ThermionicScott 

@dddd, I instantly recognized those pictures from Sheldon Brown's site. I believe he took pictures of an extremely worn-out chain for emphasis, and said that one shouldn't let it go this far.

DiabloScott

1. So the "inside" and "outside" plates thing is about shifting, not chain wear. Like the inner plate is better at grabbing bigger gears and the outer plate is better at grabbing smaller gears. I suppose there could be an "up" and "down" side of the plates too, with a "chain motion" arrow indicator; I've seen that in manuals.

2. I brought a flat sew-up into an LBS a while back and asked if they had sealant. Boomer said "no, but we can sell you a tube with the sealant already in it". I repeated "this is a sew-up". <blank stare>... "so you don't want the tube?"

madpogue 

So in short, cleaning an already-way-too-elongated chain can make it skip, right. Alternate interpretation - enough gunk on an already-way-too-elongated chain can mask the fact that it's way too elongated. I can just imagine how hard that can be to explain to an "average" customer.

Still, that's a much better explanation than claiming that cleaning the chain MAKES it longer, as the OP was told. In short - if cleaning a chain makes it skip, it was probably shot in the first place. That would have been a more meaningful explanation than the "man-splanation" the OP got. Goes right back to why it's handy either to have a chain checker, or to measure it yourself, so you go into the shop already informed.

jackbombay

This is the best summation of "cleaning chains makes" them longer.

Cleaning a chain that is in spec will not make enough of a difference to matter, and will keep it in spec longer than not cleaning it...

canklecat

Probably so. There might be a slight alignment difference in a flopped chain that could present an unworn surface. Probably not enough to matter, and side-to-side play would probably even out any wear. Any wear would be a very slight U-shaped rounded trough, measurable but not visually discernible or physically significant. I've done this only with chains (KMC and Shimano) for 7/8-speed bikes and never had any problems.

canklecat

Regarding chain skipping, the only time I've had that problem was with a new 7-speed KMC chain on a hybrid with one of those dreadful Shimano MegaRange freewheels -- one of those things with a massive jump from the 24T sixth cog to a 32 or 34 bailout granny gear. It's almost impossible to shift and maintain a smooth cadence between those sixth and seventh cogs.

My mid-2000s era Globe Carmel comfort hybrid/errand bike has an unusually long wheelbase, like it was intended to be a cargo bike but Globe (Specialized) decided to make it a comfort hybrid instead. No prepackaged chain is long enough so when I installed a new chain I had to splice two new KMC chains of the same type together.

The new chain began skipping in the three smallest cogs, worse with each smaller cog. The freewheel was far from worn out, so that didn't explain the skipping. I put the old chain back on -- no more skipping, although it was sloppy from wear.

Even though the freewheel didn't look worn I decided to replace it. But a user review on Amazon suggested the problem was with the Shimano MegaRange design -- the spacers between the cogs are too large in diameter. No problem with the larger cogs, but as you reach the middle and smaller cogs the wider parts of the links at the roller hinges (assuming typical Figure-8 shaped chain) would contact the spacers and push the chain upward, causing skipping. So it was essential to use a narrow chain (labeled as such by Shimano and KMC).

I happened to have a couple of worn "narrow" chains from another bike and decided it was worth a try. Sure 'nuff, even the badly worn narrow chains, spliced together, solved the skipping problem on the MegaRange freewheel.

But I hated that MegaRange freewheel anyway. So I replaced it with a SunRace 14-28 freewheel, which worked fine with the new non-narrow KMC chains I'd spliced together. That setup is still on the bike two years later, no problems.

I've hesitated to discard even noticeably worn "stretched" chains because they still worked fine. I just replace them every year or so depending on how much the bike was ridden... mostly because we're supposed to? I dunno. I finally got over my thrifty hoarding and threw away some old worn chains. If I had an ultrasonic cleaner I'd clean 'em up and convert the old chains into jewelry or sculpture and something to smack the hoods of cars that pass too closely.

Salamandrine 

I call BS. Where do these absurd theories come from. A clean chain is a long lasting chain. A dirty chain not only wears out itself, it wears out the freewheel/cassette cogs and chainring teeth as well. These are the sorts of theories that only sound plausible to people that don't ride many miles.

Chains should be replaced when they start to lengthen. The rule of thumb is replace before they hit + 1/16" over 12 links/inches. I swap mine a little earlier.

If a chain noticeably lengthens because you cleaned the dirt out of it (sounds suspicious), it should have been replaced long ago anyway.

Some Shimano chains do have an inner side and an outer side, as noted. There is no forward or reverse direction.

Salamandrine 

Yep, a too long chain that doesn't engage the teeth correctly will skip. Another thing is that a dirty chain will wear out freewheel/cassette teeth prematurely. This will also induce skipping, even with a brand new chain.

BITD of freewheels, when the skipping started, you knew it was time to replace the freewheel. The usual ROT was two chains per freewheel. This might be I dunno 10-12,000 miles or so. Keeping your chain clean helped extend the mileage. This skipping issue doesn't seem to come up anymore. Maybe improved materials, tooth geometry, chains and derailleurs all work to prevent it.

jackbombay

It has already been discussed in this thread that the only time cleaning a chain makes it longer is when the chain is already worn out.

TriBiker19 

And that was the oddest part--he literally illustrated (on a brand new Trek top tube) "When you pull a chain off a bike, it's going to be this long," he said, holding his fingers at the seat post and about four inches from the head tube, then he said, "you clean it and it gets this long" and he moved the finger from 4" to 1.5" from the head tube.

I'm thinking...so every time you get it dirty, you need to replace? Well that's a pain in the ass. Also, those poor MTB/gravel guys... And can you clean the cassette or does that get bigger, too?

madpogue 

The ash tray's full; trade in the Rolls....

TriBiker19 

I believe we've mostly devolved into making fun of the comment, which is kind of what I expected. I appreciate the explanations on why he might have said it, though. Thankfully, you guys don't man-splain and will actually give me real information.

TriBiker19 

But of course. Same thing as when the glove box runs out of Grey Poupon.

madpogue 

Yeah, don't worry your pretty little head about that guy at the LBS.....

TriBiker19 

See, that's the kind of response I expect. Smart, but not condescending. Much appreciated!

dddd

Good point about the special pin having to be installed in the leading hole of an outer link.

When I decide to break and reconnect such a chain, I will use my Dremel with a #85422 green (or #8215 pink) stone/wheel to take off the rivet heads from one of the link plates of the link with the special pin, then simply remove it without need of force.
I then use a KMC Missing Link to re-connect.

On newer/narrower models of Shimano chain, the grinding needs to go further inward, well below the surface of the plate, to reach the actual peening on the special pin (though the other, regular pin can simply be driven out if you like).

The special pins are generally reliable if installed properly. But, if you measure the pitch about any link so connected, it is far greater (making the special pin joint equivalent to a heavily-worn link) than the rest of the links in the chain!

So I remove any such extra links if a connecting link is to be used, even though Shimano considers them non-removable, which they pretty much are (using only a chain tool).

RobbieTunes

A Shimano chain can exhibit that behavior. Especially 9sp and 10sp. I'd say why I think so, but then some engineer/geek/expert here will tell me about the micronic differences between plates, links, etc, or lack thereof, and then I'd be proved a fool.

So, if a Shimano setup comes in with that issue, 9sp or 10sp, and the components are not worn, I check the chain. If I flip it and it works, I further the myth and go back to work. I've done it twice. Ignorance is bliss.

Now, about that demeanor you exhibit that tends to make people think you can be fooled.....setting up your mark?

RobbieTunes

I actually kept a small packet of Grey Poupon in a jersey pocket for Thunder Ridge, where they hand out regular mustard packets for cramping.

Just so I could pull it out and say it.

RobbieTunes

Perhaps "your beauty makes men forget how smart you are."

(Yes, you can borrow that.)

madpogue 

...Yeah.... and so....