I ride a fixed gear and am pretty concerned about how quickly my chain seems to develop slack. Every so often, I must slide the axle farther back in the dropout to take up extra slack. It's not the axle slipping, I made sure to check that. This most recent chain seems like it's already near the end of its life and there's no way that there's more than 1500 miles on it. Is this normal? Just FYI, it's a lower end KMC Z chain and I skid, skip, and ride through all sorts of gross road conditions. I feel like in the past, I have had better experiences with something like a SRAM PC-1. Are Z chains known for a short lifespan?

I've heard that worn rings / cogs can accellerate chain wear.

Hopefully you are measuring the elongation properly, with a precision scale and not a Park chain checker. I would not expect a cheap chain to last long and certainly not if ridden in dirty wet conditions, or if not adequately maintained.

Chain stretch is the wear between the pins and the bushing formed into the inner sideplates. When the wear on each pin/bushing pair gets to .0025 inch, you have .5% elongation.

A Campy chain will exhibit far less elongation than any other brand I've tested. If you try a Campy chain and wear it out quickly, is just proves that you're not maintaining the chain very well.

Cog and ring are in pretty good shape. I guess this means I should avoid cheap Z chains in the future. As far as chain maintanence goes....what's that involve with a singlespeed besides periodic cleaning and lubing?

Also, does campy make a 1/8 chain? How many children would I have to sell to procure such a thing?

How's your chainline? I've got a fixed gear with a $10 KMC chain that's got well over 3k kms on it and still running fine.

You can best answer this question yourself. Measure it new, and measure it now.

chain's do not stretch, maternity clothes stretch. chain's wear. Its a single speed. ride it until the chain is toast and skipping . then replace the ring, chain, and cog at the same time. you will get many thousands of miles this way, and the replacement parts are far cheaper than a new chain every 2k miles. Its not like you have to worry about shifting performance.

Good point, other than to remember not to swap out the wheel with a different rear cog. The worn chain will go to town with that cog.