Slack primary chain

mike996 said:

"its actually stronger than the crappy triplexes available nowadays"

Is that statement based on an objective test of some sort? Sounds more like an advertising claim. It MAY be true but I wouldn't buy a duplex chain for a triplex application without some DATA proving that it is better than current triplex and equal (or better) than oem triplex that, from my experience, has yet to need replacing in street use with proper lubrication.

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Based on my field experience, Chinese metallurgy is still in the Bronze Age, and Indian metallurgy is only a little ahead of the Chinese. I would not buy a hammer, axe, or any tool made of Chinese metal. When I was a jr engineer, I was given the assignment to find the best chain to use in the machinery the company used for production. My research found that all chain produced by reputable US manufacturers, meeting ANSI standards, was exactly the same in strength and wear characteristics. A little reflection gave the answer....every mfgr had access to the same steels and metallurgy, ANSI standards defined the size of the pins, rollers, and links, therefore everyone's chain ended up with the same strength and wear properties.

That situation is not the case today....chain may be manufactured to ANSI (or British) dimensional standards, but the metallurgy does not meet the strength and wear standards, thus a premium duplex chain may very well be as strong as a triplex made of inferior steels. Your point is well taken....a triplex chain of premium steel SHOULD be stronger than a duplex of the same materials, but alas, the global economy yields to the inferior products that have attractive prices.

Considering the damage that can occur when a chain breaks, it makes no sense to economize by purchasing a cheap sub-standard chain. Nor does it make for good economy to buy a cheap chain that will wear quickly and need early replacement.

Slick

swooshdave said:

How long will a chain last under-oiled?

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The life expectancy of chain depends on:

a) the degree of loading....every chain has a rated tensile load that is considered maximum. Obviously a chain running at 100% load will wear more than the same chain running at 50% load.

b) the type and frequency of lubrication.....
the best type of lube is oil bath, such as found in our motorcycle primary chain cases.
next best is continuous oil drip, wick, or brush oilers
next is intermittent application of oil or solvent based grease by pump oiler or aerosol propellant. Obviously, the frequency of application becomes an important factor.
Finally, there is basically dry running.

c) linear feet per minute chain speed.

Reputable Chain manufacturers offer charts and tables to estimate mean time before failure for these types of applications. Trying to fit a motorcycle chain to the charts is difficult owing to the operating envelope of the typical motorcycle. The motorcycle chain application is pushing the limits ( I think someone once said, every motorcycle is running its chains overloaded). I do not remember the specific numbers, (I did research on this topic a half century ago) but operating a chain dry results in chain life that is a very small fraction of the life expectancy of an oil bath application. Don't hold me to this number, but 1/100 to 1/1000 oil bath life for a dry chain is not unreasonable.

Slick

check the bottom pivot bolt has not fallen out that would explain the chain slack