# Bicycle Mechanics - Chain Reversal?

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View Full Version : Chain Reversal?

MichelleMachete
01-15-08, 07:45 PM
I was told if you flip your chain around after 500 miles that will make your chain last 2x as long. As in theory I guess it would work. But I have my suspicions .

operator
01-15-08, 08:08 PM
Why some arbritrary figure like distance that has absolutely no bearing on chain wear?

monk
01-15-08, 08:11 PM
Why some arbritrary figure like distance that has absolutely no bearing on chain wear?

You can't coast for 500 miles.

01-15-08, 08:13 PM
Not all at once at least

operator
01-15-08, 08:34 PM
You can't coast for 500 miles.

Thanks. How about quantifying chainwear for those 500 miles then?

Zouf
01-16-08, 10:50 AM
I was told if you flip your chain around after 500 miles that will make your chain last 2x as long. As in theory I guess it would work. But I have my suspicions .

There are actually 3 ways of "flipping the chain around": inside-out (same rotation direction, part of chain that was in contact with chainrings is now not in contact with chainring), rotation flip (plates that were on left side are now on right side), and both (combine both of the above).

In all cases, chain wear (a.k.a. "lengthening") is the result of wear in the pins and rollers, increasing tolerances in each pivot point and making the rollers slacker on the pins. For the flipping theory to work, the wear has to be asymetrical, and the flip must bring new, less-worn contact points into play. If you look at the (extreme) wear pixs in Sheldon's textbook article on chain wear (http://www.sheldonbrown.com/chains.html#stretch), you can see that part of the wear is indeed asymetrical: the bushing or plate extension and the pins erode asymetrically, while one can assume that the rollers, since they, well, roll, will wear symetrically.

So do you gain mileage by flipping? The symetrical wear does not care, so it won't improve that part. But the asymetrical? Unfortunately, the wear already done does not disappear, and the wear on one side of the pin still makes the chain longer, even if it's now the other side that's getting worn. In other words: wearing a lot on one side, or half as much on both sides, you still get the same total wear. It's like your socks: turning them over in the middle of the day does not make them more clean at the end of the day.

Sheldon Brown
01-16-08, 10:55 AM
I was told if you flip your chain around after 500 miles that will make your chain last 2x as long. As in theory I guess it would work. But I have my suspicions .I've got a very nice bridge to sell you...

Sheldon "Brooklyn" Brown

waldowales
01-16-08, 11:40 AM
I've got a very nice bridge to sell you...

Sheldon "Brooklyn" Brown

I only have a handful of beads. Would you sell me the bridge for that?

mayukawa
01-16-08, 01:12 PM
I think it mainly matters if you cross-chain a lot. Cross-chainining puts more stress on one side of the chain, but by flipping the chain, you then stress the less-stressed side to give it a more even amount of stretch.

Sheldon Brown
01-16-08, 01:42 PM
I think it mainly matters if you cross-chain a lot. Cross-chainining puts more stress on one side of the chain, but by flipping the chain, you then stress the less-stressed side to give it a more even amount of stretch.I don't believe it. If the chain bends left in front, it bends right in back by the same amount.

Sheldon "Not Convinced" Brown

blamp28
01-16-08, 03:23 PM
Did you know that black bikes are faster? It has something to do with the aerodynamic properties of black pigment molecules or some such thing.

rmfnla
01-16-08, 04:29 PM
No, it's because black is not a color, it's the absence of color, and removing it reduces weight. :D

peripatetic
01-16-08, 05:23 PM
No, it's because black is not a color, it's the absence of color, and removing it reduces weight. :D

I've got an invisible bike to sell you.

Az B
01-16-08, 05:54 PM
No, it's because black is not a color, it's the absence of color, and removing it reduces weight. :D

I thought black was the combination of all colors, therefore creating a bike that's faster than light.

I also have a time machine. It's not perfect, it only goes forward and at regular speed.

Az

bo_vk
01-16-08, 06:28 PM
The chain installation is directional, meaning that the chain is several times stronger when installed correctly (side plates should pull). See Shimano or maybe Park tool instructions.

operator
01-16-08, 06:42 PM
No, it's because black is not a color, it's the absence of color, and removing it reduces weight. :D

THat's impossible, if it was no colour it'd be invisible!!!1

operator
01-16-08, 06:43 PM
The chain installation is directional, meaning that the chain is several times stronger when installed correctly (side plates should pull). See Shimano or maybe Park tool instructions.

lol, I hope this is a joke.

jim p
01-17-08, 08:24 AM
I like to rotate all the pins in my chain by 90 degrees when the wear on the chain starts to reach the replacement point. I am trying to find a source of just pins so that I can use new pins after the old pins have worn too much. Maybe I will be able to find some pins that are 1/10000" larger in diameter so that they would compensate for some of the wear in the chain plates and rollers.

By the way is that bridge tall enough for bungy jumping.

Pig_Chaser
01-17-08, 09:45 AM
I thought black was the combination of all colors, therefore creating a bike that's faster than light.
Az

No white is the combination of all colours... sigh

Zouf
01-17-08, 10:24 AM
The chain installation is directional, meaning that the chain is several times stronger when installed correctly (side plates should pull). See Shimano or maybe Park tool instructions.

I'm just trying to picture a way of installing a chain in which the sides plates *don't* pull. No success so far.

Shimano only states (for 10sp chains) that you must "always shorten a new chain from the inner link side", and that you must "always insert the connector pin in the leading end of the outer link for the chain's direction of travel", and combining these 2 gives only one rotation direction possible (but still 2 sides). Then again, they are the ones that state that "a chain never be removed from the bike for cleaning", and would excommunicate anyone using a quiklink on their chains.

rmfnla
01-17-08, 11:36 AM
THat's impossible, if it was no colour it'd be invisible!!!1

There's a difference between "black" pigments and true black.

Why do you think night looks black?

rmfnla
01-17-08, 11:37 AM
I've got an invisible bike to sell you.

Sounds fast...

oldster
01-17-08, 01:02 PM
You can only do that to a Left handed chain, You need to check, in case yours is Right handed....

Bud

mayukawa
01-17-08, 03:48 PM
I don't believe it. If the chain bends left in front, it bends right in back by the same amount.

Sheldon "Not Convinced" Brown

I haven't done any measurements, so this was just a hypothetical argument. The width of the teeth don't perfectly match the width of the chain openings, so there's some wiggle room. The front will have more teeth to hold the chain, so I was thinking that the front and rear will not bend by the exact same amount, due to more stress per teeth on the back. I think you're modeling the chain as a straight line, while I think of it more as a relatively straight curve. Chains do have some side-to-side flex capability, so unless the angle exceeds that flex amount, I don't think there will be much of a difference. Again, just a hypothetical argument.

sivat
01-18-08, 01:06 AM
Did you know that black bikes are faster? It has something to do with the aerodynamic properties of black pigment molecules or some such thing.
A black bike alone won't make you faster, you need to pair it with a white saddle and bar tape. It's the balance between the black and white molecules that make you fast. That's why all the TdF riders do it.

spencejm
01-18-08, 09:18 AM
Why do you think night looks black?

Because it's dark.

mark9950
01-27-08, 08:33 AM
Why not do it before every bike ride you take then?