Ordered an IRO wheelset (oh how I've heard good things) and was curious how an old Sugino BB lockring would work as a lockring on the hub? Or should I suck it up and pick up a lockring when I pick up a cog at the LBS? I'm just not sure if the threading/size is correct.

The threading and size is different...a proper lockring is smaller and threads reverse of the freewheel. You'll need to buy one...they're cheap.

https://businesscycles.com/trpart.htm#lockring

formula lockrings are 6.50 and he ships the day you order.

**** it, iro lockrings are four bucks just order one with the wheels



although i broke one of them once cause im an *******, but whatever, its four bucks.

Being an idiot, I love making things difficult. Instead of thinking ahead (like normal people do) I choose to act on impulse then regret my haste later. Wheelset gets in Tuesday and I'm hoping to have all my ducks in a row so I can just assemble and ride. I guess it's back to the LBS.

Anyway, while I'm at it, is there a significant difference between separate brand cogs in the $20-$25 range or is it the same ol' what you pay is what you get?

There are differences between the precision and hardness. Precision will determine whether you will ever be satisfied with the chain tension (juggling tight and loose spots).

Just a caution, there are severial hub locknut standard, make sure you get the correct one

what do cogs have to do with chain tension? i know of chain rings, but never heard it blamed on cogs.

if the cog is not round its the same as the chain ring not being round

It'd be really hard to make a seriously out-of-round cog, though... My $2 cog is round. I'd consider that a case of the maker deliberately ****ing you in the ass. (If you're into that sort of thing, then insert "...refusing to ****...")