Track nuts
 

Last night I was riding, and did a sprint up a hill. Came up to a stop sign, and my rear wheel came loose in the dropouts. Took off the track nuts, and the serrated section is completely smooth. Could it be from over torquing the nuts, or did it wear our from age? These were cheapo oem nuts that came with an Alex R450 flip flop wheel. Should I get a different set of serrated nuts, or is there a better design out there?

Dave

Are they "proper" track nuts, in other words, nuts with a captive serrated washer, or are they just serrated flange nuts.

Here are proper track nuts
https://cimg4.ibsrv.net/gimg/bikefor...0d397982f8.jpg
https://cimg0.ibsrv.net/gimg/bikefor...b168b15d5d.jpg
You can see the design has an integral, free floating washer attached. The serrations on this type of nut should not wear out as the nut is free to rotate and tighten on the axle, as the washer bites into the dropout and doesn't move.

Then there are serrated flange nuts. These are sometimes sold as track nuts when you can get them in the proper metric threading. They are a cheap substitute for a proper track nut, because they can be found from almost any fastener wholesaler for pennies. These nuts WILL wear out with repeated tightening and loosening of the wheel. They will also wear down your dropout faces over time as well. This is because the serrations are actually part of the nut, and don't rotate freely. So they actually wear out, and grind down your dropout at the same time.
https://cimg5.ibsrv.net/gimg/bikefor...a732d05c1a.jpg
https://cimg7.ibsrv.net/gimg/bikefor...3fa074147f.jpg
If these came on your wheel, then order some proper track nuts and life will be better again.