Home | Shop Talk | Background | Instruction

Shop Talk | Chain Discussion 1

Chain replacement is one of the most common service items on a bike that is ridden a lot. It is also the culprit for a lot of other drivetrain issues. With such a crazy variety of rider types and preferences, chains come and go pretty quick.

Standard wear protocol dictates that you measure your chain occasionally to determine if it is stretched to the point that it will cause excessive wear to the cassette and chainrings. At that point of replacement, it costs less than waiting and replacing chainrings. Also, as chains wear they get sloppy: they don't shift as well and make a lot of noise, they also break. As for wearing out a cassette, those are never cheap, not even the cheap cassettes.

If you're running Campagnolo Record or Super Record, Shimano Dura-Ace, or SRAM Red cassette that includes aluminum and titanium parts, then you're heart has stopped at least once when you had to lay down several Benjamins in order to replace it. It doesn't matter if you're on a mountain bike or a road bike, the system still works the same way.

So your mechanic, me, calls you and explains it's time for a new chain. You say, "I just replaced that last season!" and then your mechanic begins to break down how chains just wear through regular use, shifting, cross chaining, climbing, body weight, riding preferences including terrain, and so forth. There's a lot that goes into chain wear. Replacing it is normal and the least expensive part of your drive train system.

I use a Park Tool CC-2 Chain Checker. It's one of the few Park Tools I think is reliable and moderately well made. In the measurement window, 0.25 is roughly a new chain whereas 0.75 is time to replace for optimal wear. Beyond that things start to wear more rapidly; this goes for chainrings and cassettes as well.

Replacing a chain is not a time thing either. It is more relative to time in the saddle, even more than miles. But since that is hard to calculate, checking the chain stretch with this inexpensive tool is a whole lot easier. It's something that every home or garage mechanic should have.

An important note, replacing your chain on time prolongs the life of the other gear. So be aware, you're going to replace rings and cassettes anyway. The more you ride the more often this will happen. By replacing your chain at proper time intervals, you'll exponentially stem replacing cassettes and chainrings.

-- Insight --