Singlespeed & Fixed Gear - lockring troubles

After lurking around these forums for a long while, I finally decided to build my first fixed gear (I singlespeed one of my mountain bikes), but I seem to have run into a problem. I have a rear wheel from IRO Cycle (IRO hub with a velocity rim), and I recently bought a Dura Ace lockring, but I can’t fit the lockring on the hub, it seems to be too small. So I went to the sheldon brown website to see if maybe I bought the wrong brand of lockring, but I don’t think I did. So my question is: did I buy the wrong brand, am I crazy/stupid and trying to put the lockring on the wrong way, or is there something else that might be amiss.

Are you working with the 135mm hub? I think all of the IRO hubs should accept that ring, but I know for a fact that the 135mm double-fixed hub will take a DA lockring as that is what I recenty built up with. (And took out in the snow just tonight--kick ass!)

Are you threading it on properly (reversed)?

the lockring is left hand thread,
left to tighten
right to loosen

not sure if you knew that
if you did, then i don't know why it doesn't fit, unless you have mangled threads on your hub

Could it be possible that you have the single speed hub? A fixed gear hub should have two steps of threads, one regular threaded (for the cog) and a smaller one outside of that which is left (reverse) threaded (for the lockring).

Seems like you know a fair amount, but just in case you didn't know about this.

i have iro hubs and and a dura-ace lockring, so it must be something other than brand compatability.

The hub is 125mm spaced, it is a fixed/free flip flop, and i believe im threading it on right. What exactly would mangled threads look like. Maybe i will bring the wheel up to my lbs today and see what they say, i dont know if they have much experience with fixed gears though, but i have seen a few fixies in blacksburg so who knows.

you might be able to tell if the threads are mangled just by looking at them closely, or you coud try sliding a fingernail through the threads to see if they feel smooth.

ok so it looks like maybe a spot or two on the first or second thread might be a bit messed up, what should i do? Since its right at the beginning should i try and force the lockring past it, or could i file the threading down, or should i just send the wheel back and email tony?

i wouldn't try to force it,
if you accidentally put it on tweaked a bit it could completly strip the threads and make the lockrings less secure or not secure at all.
i would talk to tony, IRO may have had this happen to some of their hubs and be familiar with the problem.

if it's justa a little mangled you could try to -carefully- remove only the bits that are in the valley of the thread with a very thin file. the very thinnest file i have or have seen is not thin enough to do this with out taking a little more than necessary but if you're careful you should be ok. remove as little as possible! you might also try cutting out any offensive aluminum with a utility (stanley) knife if you dont have a very delicate file. the steel lockring should be able to take on a little roughness on the aluminum hub.
of course using a proper thread chaser or sending it back is the very best way to have this handled, but no one will have that thread chaser and mailing it off will take time/money.
there's no right answere here, you've got a couple of options. If you do take it to your lbs, go when they're not busy, and they help you out for free, buy something from them.