1" threaded headset cups don't fit in head tube...
 

Just when I was finally satisfied that I knew what I was doing, this comes up. :mad:

I'm working on redoing my old fixed conversion, based on a lower-end early '70s Fuji steel frame, prolly was an S-10-S or maybe a step above... nothing too fancy.

It's just a cheapy "Inline" brand BMX headset, seemed good enough, better than what I had, and was the only 1" threaded that the LBS had. It has an ISO crown race, which fits my fork just fine. But the cups will not go in the head tube without something breaking... I'm not talking just the 30mm vs. 30.2 troubles some people have with ISO vs. JIS, these things measure around 32mm. WTF?

Does BMX use an even different standard from the two existing 1" threaded sizes I already know about? Or did I just manage to get one that was made the wrong size?

Oh, and BTW, hi, I'm new here. You'll prolly be seeing a lot of me around these forums, seems like a pretty sweet hangout. :beer:

You need to get a road bike headset. BMX headsets, which is what you say that you have, use 32.7mm cups.

RG's got your answer

Alright, figured as much. So... just how many different types of 1" threaded headsets are there, anyway? Any others I don't know about?

And since I apparently now have to get one online, how do I avoid this happening again? They don't always specify the intended application... Are the Nashbar 1" headsets road bike size?

Take a look at Sheldon's cribsheet on headsets:
http://sheldonbrown.com/cribsheet-headsets.html

Alright, cool. Thanks for all the info.

So, for future reference, is there any easy way to tell the sizing standard of a headset when it isn't listed on the site? I mean, like, Nashbar doesn't give any of the actual measurements of theirs and Google turns up nothing either... so do I just have to contact the company or ask on here anytime I need a new headset on a bike? It seems kinda ridiculous to me, if there are multiple standards they should at least specify which standard they use...

I've called Nashbar on unlisted critical information, you would think they would add it to their website, but I've never seen a description changed (right hand doesn't talk to the left). If it's not a Nashbar part, you can do what their tech dept does - pull up the manufacturer's website - I've heard them do it while I'm on the phone with them.