Yah, wouldn't trust that w/o a lockring.
FWIW, last time I installed a cog I screwed it on the wheel and then put the cog into a vice with thick wood in the jaws. The cog's teeth dug into the vice wood deeply as planned. I turned the wheel to tighten the cog and watchd in amazement as the cog rolled the wood blocks right out of the vice. So I guess it would work if the wood was actually attached to the vice by more than just pressure.
In any case, it was tight and we just finished it up with the cheapo nashbar chainwhip. lockiring followed with the cheapo nashbar lockring tool.
Originally Posted by earjob
ah, beaten to it. i put a lockring on as well after tightening down the cog - i don't see how even the tightest cog would stay on after enough stopping w/o a lockring right?