• 2 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
    WR = 2st Enduro & CR = 2st Cross

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    As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.

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All 2st O-ring chain ?

I have a rear sprocket that has not had much use and i am thinking of running that with new front and chain
Rear oem sprockets don't seem to wear Or dont appear worn. Yet I guess they are worn
 
They absolutely stretch as well as wear.

Common misconception that an oring chain's lube is sealed inside. True, the lube for the solid pin that the chain pivots on is sealed by the o-ring. But the roller that contacts the sprockets rides on a bushing and is open to the elements. Oring chains still need to be lubed to lubricate that roller/bushing.

So what exactly stretches on a chain, then?



Chains really don't stretch but as they do their job the lubricant between the pins and bushings is burned off by heat, pressure, and friction; lose enough of the chain's lubricant and rapid chain wear, takes place. As the various parts of the chain rub against each other, wear develops between the pins and rollers. With the wear, the chain elongates.

From here
http://www.bikerenews.com/Stories_Archives/Chains.html

But you can also find it on chain manufacturers websites

The lube IS on the inside. Any lube on the outside of the chain is not significantly important.
 
So what exactly stretches on a chain, then?

I agree with you that chains don't "stretch" in the normal sense of the word (elastic/plastic deformation). However, often when people say "stretch" they mean elongated due to wear.

The lube IS on the inside. Any lube on the outside of the chain is not significantly important.

Lube on the outside would be a significant factor in chain/sprocket wear, no?
 
i remember seeing a documentary about chain lubrication on container forklifts the end result being less wear and better performance from a lanolin based oil, i use lanotec on my chains as it seems to coat and penetrate without having all the crap stick to it as much as chain lube, i pressure clean after every ride and spray with lano all parts that might need a hit, everything eventually wears but i prefer this to the ultra sticky chain lube that can increase wear by collecting abrasives.
 
the last non-o-ring chain I had I had to adjust it @ the beginning of every ride. not sure of the brand but ive ran a lot of DID x rings chains since then and really liked them. I just switched to a RK XW ring chain and its even better that the DID.

ive found that if you want to test a chain put on a trials tire and got find some rocks. if anything will stretch it out that will.
 
small 125 non o ring chain was fine, i use x ring on my 360 not had to do any adjustment for ages, i soak my chain in used gear oil from the tranny 2 birds one stone.
use oil not wax if you like your sprockets, also keep your eye on the front sprocket as it does the most work.

rk = awesome chain sofar.:thumbsup:
 
So what exactly stretches on a chain, then?

The lube IS on the inside. Any lube on the outside of the chain is not significantly important.


We sell around 100 units a month at the dealership. During summer months a majority of them are motorcycles. I guarantee I have a firm grasp on the subject of chains and likely have dealt with more chains in a month than most will in their lifetime.

A new streetbike can have the chain adjusted properly at setup before use. you can run it on a stand and the chain remains properly adjusted. Now take it for the initial testride: If you just putter it, the chain stays in adjustment. However if you grab the throttle a bit and accelerate hard JUST ONCE for a less-than-a-mile testblast, the chain is FLOPPING GOOSE LOOSE. Now are you trying to tell me it "wore" loose in 20 seconds and one mile? Because the lube burned up? Don't be ridiculous of course chains stretch.

Now, inspect that chain a little closer. See the roller that contacts the sprocket? See how it spins on the bushing? Explain why the lube sealed in the joint by the oring is so important, but lube between the roller and bushing is "not significantly important"?

It really matters not to me what chain you use or how you treat it... But you are posting mis-information.
 
So what actually stretches then?

I'm siding with the chain manufacturers on this one.

The rollers do just that. They roll. That's why the lube on the inside is so important, and O ring chains last and non o ring chains don't, because it's the inside of the chain that requires the lube. On the outside lube would be nice, but between the heat, friction, and centrifugal force, nothing is going to stay on the outside of the rollers long enough to make a difference, and the rollers are hard, and built to take that. Chains fatigue on the inside, not the outside.

I've changed miles and miles of industrial chain, which typically is very well lubed on the outside and they fatigue exactly the same as bike chain, from the inside.
 
You can't pre- stretch a chain. They don't stretch. They wear and the tolerance stack up makes them longer.
For sure, as a roller chain wears the clearance between the pins and rollers increase and the wear accelerates until destruction. The early part of the chain life is when there isn't as much gain in length/need for adjustment. It doesn't matter if it is an o ring chain or not the principle is the same. The o ring chains just don't wear as fast as non sealed chains.
As a side note,
about 25 years ago Cat came out with SALT (sealed and lubricated track) drive chains for their tracks, which extended the life considerably and has become the industry standard for heavy equipment.
 
Chain_parts400.jpg


Now, inspect that chain a little closer. See the roller that contacts the sprocket? See how it spins on the bushing? Explain why the lube sealed in the joint by the oring is so important, but lube between the roller and bushing is "not significantly important"?

I can't answer that and I'm not sure it is not as important...Unless the load that is carried on the inner pin is somehow taking such a high portion of the load that it makes this 'roller wear' small-time in the process of chain-wear as compared to the load pin ...

Pitch is the distance between 2 pins on the same link .. If this chain is to stretch, the pitch is gonna change because the plate must stretch, unless that outer plate stays in tact and that inner plate hole stretches or elongates. This will keep the pitch but stretch the chain. Slack created by this inner plate holes stretching would be easy to find in a worn out chain.




On the outside lube would be nice, but between the heat, friction, and centrifugal force, nothing is going to stay on the outside of the rollers long enough to make a difference, and the rollers are hard, and built to take that. Chains fatigue on the inside, not the outside.

I can't really see the point in bold ... It sounds believable, but I'm run chains on my motorcycles with out much or any oil, but it just did not work out for me.

See this pic? That's my chain after a ~35 mile ride. I'm not sure what is making my rollers and inside my sprocket teeth a dark dull color, but I'm OK with it.

After I put used engine oil on my chain, inside my chain guide, on the chain slide, and anywhere else it might it need it, the chain color is dark of course and stays black looking for a ride or two, then starts turning very silver and shiny if no oil is applied... Next stage is the sprocket is all shiny sliver ..... A few more rides with that silver chain and it's toast along with the sprocket.
496_0041.JPG

Check the ride reports and Kopiko races I've logged for chain and sprocket usage last yr. Most of my rides are < 60 miles and maybe that helps with the longevity of this hardware.
 
It's just a problem of terminology. The metal in chains doesn't "stretch" in the technical sense of the word. Chains get longer (pitch increases) due to wear between the moving surfaces of the chain.

That being said, a lot of people say "stretch" when they really mean "elongate due to wear." There's probably no reason to worry about it too much.

As chains wear/stretch/elongate (call it whatever you want), the pitch definitely increases. This is why they wear out sprockets. Any decent manual of chain manufacturer will have a spec for maximum allowable pitch.
 
Right on. You guys are googling "chain stretch", and haven't actually OBSERVED THE BEHAVIOR of several thousands new chains in the first few minutes of their life with a MOTORCYCLE under varying torque loads. It isn't wear, and it isn't a terminology issue, something else is at play. Carry on.
 
Right on. You guys are googling "chain stretch", and haven't actually OBSERVED THE BEHAVIOR of several thousands new chains in the first few minutes of their life with a MOTORCYCLE under varying torque loads. It isn't wear, and it isn't a terminology issue, something else is at play. Carry on.

Plastic deformation caused by tensile stress would occur in the first few minutes of life...
Then after.... the moving parts would wear and elongate the chain.

Do I win? :D
 
Plastic deformation caused by tensile stress would occur in the first few minutes of life...
Then after.... the moving parts would wear and elongate the chain.

If you're plastically deforming your chain, especially in the first few minutes of its life, you've got really big problems.
 
I'd like to know more on the "pre-stretching" process that many roller chain manufacturers claim happens in the factory.
What actually happens to the chain...
:excuseme:
Does elastic deformation occur?
Does plastic deformation occur?
Do the moving parts wear during the process and elongation occurs?
Does it simply align all the parts?

:popcorn:
 
If you're plastically deforming your chain, especially in the first few minutes of its life, you've got really big problems.

Or an insane amount of horsepower.

Think about this: You have a mechanical device with over 200 moving parts, all with clearance in the same plane. The first time you pull it hard in one direction, even if each one moves only .0005" (that's half of one thousands of an inch - see how little that is), you'll see about .125" difference in the length. Anybody who has installed a belt or chain knows that's a significant, and noticeable difference in length.
 
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