Batavus

hi everyone,

Let me start by saying that I really enjoy reading this forum and soak up all information here on fixies. I am new to the fixed thing, but recently completed my first fixie, a Batavus late eighties 10 speed. Respaced the axle and redished the rear wheel. Pulling the rim about 3/4 inch to the left and trueing the wheel was a fascinating first time experience! Reading the fixed-gear testimonials and rants (Sheldon Brown, etc), I thought geez, these guys (and girls), what the f***k are they on about, talking about 'a Zen-like experience', cadenced trains of thought and what have you. But now I'm officially hooked. It's sad and I never thought the cliche would become a reality for me so quickly, but it's the best decision I've made in a long, long time!

But here's my question: I am running the original (worn, but far from terminal) small front chainring (48) with a 17 rear cog (my LBS says it's not a real track cog, but rather one that fits a kickback hub) and a 1/8" chain.
Chainline is about 1-1,5 mm off, but still pretty straight and properly lubed the chain is almost dead silent. But now I'm seeing my chain go slacker after every(short) ride. The axle (quick release) hasn't visibly moved forward, but something must be going on here. Did I just buy a crap chain, or is it normal that it stretches this fast? ? It's not top stuff, but certainly not cheapo.

Any tips would be most appreciated!