Tech Tip 24 Why O Ring chains Wear out

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Tech Tip #24 Why O-ring Chains Wear Out
 
The short answer is metal abrasion, the wearing away of metalundefined makes the chain stretch and wear out. How? In a 100 link O-ring chain there are 100 pins and 200 O-rings. The sealed-in lubricant coats the pins and prevents metal-to-metal contact. As the internal lubrication looses its effectiveness, it is forced away from the high load areas of the pins, the trailing side. This is where the wear occurs because the engine torque tries to stretch the chain and the chain’s rollers are forced apart and they press against the pins. As long as the lubricant is there to cushion the shock, the chain doesn’t wear. When it is gone or displaced to the leading edge of the pins, you get metal-to-metal contact. As each pin wears a minuscule amount it allows the rollers to move apart by that amount. Multiply that amount by, in this example, 100 times (links) and you get chain stretch that must be compensated for by, most typically, increasing the distance between the countershaft sprocket and the rear sprocket.

If you want to accelerate wear in an O-ring chain, leave it dry and rusty. As external corrosion, i.e. rust, builds up on the chain, and the inner part of the sideplate that contacts the O-ring becomes rough from rust, it quickly abrades away the O-ring until it is cut and the broken piece is forced out from between the inner and outer sideplates. This opens up a pathway to the outside for the external lubricant to escape as well as for water/dirt entry.

The external lubricant you apply must not be sticky or dirt will be attracted to the chain and the O-rings can be cut by a sharp piece of debris, like sand. My preferred O-ring chain lubricant is Maxima Chain Wax. “Why is my sticky chain lube rated for O-rings? It says so on the can?” All that means is the chemicals in the can have been tested to not deteriorate the rubber of the O-rings and cause cracking and hardening.

 
O-ring Chain Pop Quiz

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1. How many sideplates are visible?
2. How many rollers are visible?
3. How many pins are visible?
4. How many O-rings should be visible?
5. How many O-rings are actually there in the chain section shown? 6. What is the condition of this chain?

 
Answers:

1. 10
2. 4
3. 4
4. 8
5. 1
6. It is now relegated to cement fill duty. Works as good as wire mesh at preventing cracks!

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