Refitting chain orientation question

[PT1029]

A friend has asked if I have a way of "marking" a chain to note its orientation when removing for cleaning (so it can go back on the same way).
The chain (Sram 8s) is being used on hub gears with no chain tenioner.
I guess the answer is it is hard to mark a hardened dirty/oily steel plate.....! Plus, in this age of quick links, no orientation is easily discerned. If using pushing the pin out method to remove the chain, then you have a reference.
My friend in travelling for some period, so doesn't have access to one of those chain cleaning baths things (which are hard to used on none derailleur gear chains anyway.
My points below assume the chain pins are fixed to the outer plates, and all the wear is due to the inner plates rotating on the chain pins.
However, it made me ask if the orientation when refitting is important or not.
So, if you turn the chain round (so it runs "backwards" compared to previously), I guess it makes no difference, all other things being equal. (The same parts of the inner plates/pins rub together as they are still in tension when you push on the pedals)
However, the chain links (on hub gears at least) always flex the same way when they go round the chain wheel, and round the sprocket, so only a certain section of the chain pin gets worn (and turning it "back to front doesn't alter this).

If instead, you turn the chain what I will call inside out (so the parts that used to face inwards/towards the BB axle/hub axle now face outwards), the inner chain plates will now flex the other way, only previously unworn parts of the chain pins.
If this is so, will the chain last longer as you are using a greater part of the pin surface by turning the chain inside out?

On derailleurs this is probably irellevant as the chain flexes both ways round the derrailleur jockey wheels.

[tim-b]

Hi
I don't know the answer to your question on wear, but in terms of marking the orientation after removing the connector link I loop a nylon cable tie through the forward end roller on the top run where the connector link should sit
If you always poke the end of the cable tie through the roller from the outside of the chain to inside then you have an easy system to follow. The cable tie also gives you a hanging loop to drain the cleaned chain (just don't pull too hard and snap the cable tie!)
Regards
tim-b

[Brucey]

most chains are assembled using marked but randomly oriented side plates, which means that one of the two chain ends may well have a distinctive arrangement of side plate marking. This may be enough to allow the chain to be fitted 'the same way up' again.

Similar considerations do apply to derailleur chains; although the chain flexes the other way through the rear mech, there is little load so the bushings don't wear much in that way.

Chains and sprockets wear together, so that there is potentially a slight mismatch if the chain is refitted the wrong way up. I don't think that there is any great advantage by so doing; if anything I'd expect slightly rough running ( similar to fitting a new chain on worn sprockets) for a while if the chain is refitted the wrong way up.

BTW a common error is to adjust a worn chain too tightly. Once a chain is a bit worn, it should be allowed enough slack so that the rollers can ride up the teeth so that the worn chain pitch matches the pitch of the teeth. If a worn chain is set too tightly, it results in rough running and greatly accelerated rates of wear.

cheers

[MikeDee]

I read that a Shimano rep said to reverse the direction of the chain to get better wear out of it (assuming it isn't an asymmetrical chain).

[rjb]

I read that a Shimano rep said to reverse the direction of the chain to get better wear out of it (assuming it isn't an asymmetrical chain).

But did that mean turning it around or turning it inside out. You have a choice of four ways.

[MikeDee]

I read that a Shimano rep said to reverse the direction of the chain to get better wear out of it (assuming it isn't an asymmetrical chain).

But did that mean turning it around or turning it inside out. You have a choice of four ways.

Hmmm... That's why I don't bother to keep track.

[Gattonero]

A friend has asked if I have a way of "marking" a chain to note its orientation when removing for cleaning (so it can go back on the same way).
The chain (Sram 8s) is being used on hub gears with no chain tenioner.
I guess the answer is it is hard to mark a hardened dirty/oily steel plate.....! Plus, in this age of quick links, no orientation is easily discerned. If using pushing the pin out method to remove the chain, then you have a reference.
My friend in travelling for some period, so doesn't have access to one of those chain cleaning baths things (which are hard to used on none derailleur gear chains anyway.
My points below assume the chain pins are fixed to the outer plates, and all the wear is due to the inner plates rotating on the chain pins.
However, it made me ask if the orientation when refitting is important or not.
So, if you turn the chain round (so it runs "backwards" compared to previously), I guess it makes no difference, all other things being equal. (The same parts of the inner plates/pins rub together as they are still in tension when you push on the pedals)
However, the chain links (on hub gears at least) always flex the same way when they go round the chain wheel, and round the sprocket, so only a certain section of the chain pin gets worn (and turning it "back to front doesn't alter this).

If instead, you turn the chain what I will call inside out (so the parts that used to face inwards/towards the BB axle/hub axle now face outwards), the inner chain plates will now flex the other way, only previously unworn parts of the chain pins.
If this is so, will the chain last longer as you are using a greater part of the pin surface by turning the chain inside out?

On derailleurs this is probably irellevant as the chain flexes both ways round the derrailleur jockey wheels.

Reversing the chain in the direction of travel makes no sense, because the wear of the pins and the rollers is always in the inner face of each link doesn't matter which direction you pull.
And unless one rides constantly with the chain in an angle (i.e by riding only the first or the last couple of sprockets in a multiple cassette) there's no benefit by flipping the chain Lh/Rh either.
In fact, you better go single-speed or use a 5sp freewheel or a 3sp hubgear!

Those pictures say a lot, note the wear is only on the inside face of this track chain, the outer face is actually rusty and corroded




while this is a "bushingless" chain as are all the chains for multiple speed use (7, 8, 9, 10 etc.), same SRAM PC10 chain but the one on the left is pretty worn and you can see the wear on the pin -also note the wea on one of the sprockets, at the top- versus the perfectly smooth pin of the same chain when new

[MikeDee]

A friend has asked if I have a way of "marking" a chain to note its orientation when removing for cleaning (so it can go back on the same way).
The chain (Sram 8s) is being used on hub gears with no chain tenioner.
I guess the answer is it is hard to mark a hardened dirty/oily steel plate.....! Plus, in this age of quick links, no orientation is easily discerned. If using pushing the pin out method to remove the chain, then you have a reference.
My friend in travelling for some period, so doesn't have access to one of those chain cleaning baths things (which are hard to used on none derailleur gear chains anyway.
My points below assume the chain pins are fixed to the outer plates, and all the wear is due to the inner plates rotating on the chain pins.
However, it made me ask if the orientation when refitting is important or not.
So, if you turn the chain round (so it runs "backwards" compared to previously), I guess it makes no difference, all other things being equal. (The same parts of the inner plates/pins rub together as they are still in tension when you push on the pedals)
However, the chain links (on hub gears at least) always flex the same way when they go round the chain wheel, and round the sprocket, so only a certain section of the chain pin gets worn (and turning it "back to front doesn't alter this).

If instead, you turn the chain what I will call inside out (so the parts that used to face inwards/towards the BB axle/hub axle now face outwards), the inner chain plates will now flex the other way, only previously unworn parts of the chain pins.
If this is so, will the chain last longer as you are using a greater part of the pin surface by turning the chain inside out?

On derailleurs this is probably irellevant as the chain flexes both ways round the derrailleur jockey wheels.

Reversing the chain in the direction of travel makes no sense, because the wear of the pins and the rollers is always in the inner face of each link doesn't matter which direction you pull.
And unless one rides constantly with the chain in an angle (i.e by riding only the first or the last couple of sprockets in a multiple cassette) there's no benefit by flipping the chain Lh/Rh either.
In fact, you better go single-speed or use a 5sp freewheel or a 3sp hubgear!

Those pictures say a lot, note the wear is only on the inside face of this track chain, the outer face is actually rusty and corroded




while this is a "bushingless" chain as are all the chains for multiple speed use (7, 8, 9, 10 etc.), same SRAM PC10 chain but the one on the left is pretty worn and you can see the wear on the pin -also note the wea on one of the sprockets, at the top- versus the perfectly smooth pin of the same chain when new

When the chain rolls over the cogs and chain rings, the links articulate over a certain number of degrees. When you reverse the direction of the chain (same side facing outwards), the chain articulates over a different area. Going through the jockey wheels causes no wear because the chain is under light tension.

[Gattonero]

If what you're saying was true, there will be wear on a certain angle, while the picture shows the wear been symmetric. This is consistent with laws of geometry: for a given angle, whether is conves or concave the flex is the same. Given that the chain is going to pull mostly on the teeth towards the chainring -in the upper branch of the chain- to think that will make difference by reversing the chain is splitting hair at best.
You're welcome to provide pictures that show wear of the chain pins on an angle relative to the vertical.

While if we talk about the horizontal wear, this shows that even on a 5sp setup there is horizontal wear

[Brucey]

most of the wear is in the tension direction as you say, but (esp if the chain has been used much on small sprockets) a proportion of it is not and is skewed. This skewed wear isn't always distributed as you might expect, either, being mostly evident on every other pin/bushing (because of the way the links articulate as the chain comes away from the sprocket; by contrast the angles as the chain enters the chainwheel are so small that you would struggle to see anything). There is also uneven wear on the outside of the half-bushings, where the rollers bear against them.

FWIW the biggest skew angle you are likely to see is ~30 degrees if the chain has been used (lots and lots) running on a 12T sprocket.

cheers

[Gattonero]

Surely the wear of the roller is equally important (that's why I like to include it in the chain wear) but we assume this is constant all around.
IMO, a bicycle chain may be working in very hard conditions, and with a wide spectrum of peak and frequency of power input that is applied onto. All those variables are way more important than thinking of reversing the chain for making it lasting longer.
Seriously, this may be a matter to talk only for a chain that is kept exceptionally clean and well lubricated, free from dust or dirt, and is used under even loads. Given the cost and time required for a thorough cleaning of the chain twice a week, this will make more cost-effective to replace the chain when it needs to.

[Brucey]

I agree that refitting the chain differently is unlikely to provide any real benefit (as per my comments upthread) but I also note that 'the purpose of roller bushing wear' is to help keep the chain a constant pitch, as the chainwheel and sprocket teeth see it.

Without roller wear, the chain would soon develop an uneven pitch (as the teeth see it, every other link would be a different length), since pin bushing wear alone naturally develops that pattern. Some singlespeed chains do develop such a wear pattern (and a matching pattern is established on sprockets and chainrings with an even tooth count), but rollers on derailleur chains normally wear fast enough (and don't stay on one chainring/sprocket long enough) such that they don't usually develop a similar pattern (*).

It is as well to remember why we measure chains for wear; in effect it is as a proxy for chainring/sprocket wear in most cases, i.e. one hopes to avoid destructive wear on chainrings and/or sprockets by replacing the chain early enough. Chains that are worn more than ~1% will ruin the rest of the transmission but it may take thousands of miles more before it slips or runs so rough that the bike stops working.
In theory you could have a chain with very worn roller bushings and no pin bushing wear. In reality this doesn't happen and even if it did it might not result in bad sprocket wear. Roller bushing tolerances are not uniform between different models of chain.

Thus chain roller wear could be considered either to be fairly irrelevant or simply that it occurs naturally in response to pin bushing wear. If you look at roller bushings the rollers themselves 'wear thin' and the parts they bear against do not wear evenly; typically the half-bushings in the side plate tend to wear into an (asymmetric) oval shape.

In any event you can include roller bushing wear in chain wear measurements, but ultimately this is likely to be a little misleading; one only needs to measure a few new chains of different manufacture (and to get different 'wear measurements' on them, in contradiction to overall length measurements) to confirm this.

(*) I was recently reminded of this when I examined that rare thing, a derailleur setup that had been used in one gear only (with even tooth counts front and rear) for long enough, under bad enough conditions to wear the chain out. The freewheel was (in contrast to most modern HG sprockets) fitted with hard and wear resistant sprockets, and the wear/tooth loading was so uneven that (pretty much) every other tooth had broken off the sprocket, because (following an occasional gear shift) they had seen uneven loading from the chain, in which roller wear had presumably been unable/unforced to keep pace with pin bushing wear.

cheers

[PT1029]

Thanks for the detailed replies. All much as I was thinking... in reality with cycle mechanics, we can discuss how to do things all day long. The bottom line (mostly) is not so much how you do it, but as long as you do it properly/correctly, how you do it doesn't really matter that much!

Cheers.