Hello, my drivetrain setup is Sugino 75 cranks w/ BB and Chainring, Phil Wood high flange hub w/ Dura Ace cog and Izumi V "Super Toughness" chain.

My drivetrain ran smoothly and quietly before I upgraded my cog. I had an EighthInch 3/32 cog, but now that I have the DA cog, it's significantly louder. The chain has no stretch, chainring is in good condition, so what's up with the cog? I got it used but it's in good shape

Try lubing your chain.

Maybe your chain is too tight, in addition to needing chain lube.

Thing is, I completely degreased my chain and relubed last week with Finish Line Dry Teflon lube. I've ridden about 40 miles with the EighthInch cog and it was quiet and smooth, I got the DA yesterday and now it's making noises.

I'll relube and see if it helps though, can't stand this noise!

It's pretty loose, I have about 1/2 inch of slack

I had a similar issue. Had a silent drivetrain with some miles on it, stuck a new chain on and it started making a horrible grinding noise under load. Heavy chain lube like Tenacious oil or Chain-L helped a bit, and after a couple hundred miles of riding everything wore in and the noise went away.

You can't always tell if a cog is "in good shape" by looking. If you did not alter the chainline or mount the wheel with too much chain tension the cause of the excess noise has to be the cog, and the only reasonable explanation for excess noise would be wear.

"what's up with the cog? I got it used but it's in good shape" You can tell little about a cog's condition by looking at it. If it is making noise with an un-worn chain it or the chain is probably more worn that you think. Did you use a rule (preferred) or a chain checker to determine the condition of the chain? If the drivetrain ran quietly before and it does not do so after changing the cog it would seem logical to conclude that the cog or its interaction with the chain is the problem.

Yes, I measured the chain for wear and there was none. I also bought it off a friend and he said he rarely used it and only on the track.

While this is properly a "bike mechanics" question, have you asked in SS/FG? Some cogs are known to be noisy, at least when new.

- Scott

lol well turns out it was a dry chain. Funny, I lubed it a week ago, and rode less than 100 miles! Does teflon lube just not last?

The way I'm lubing is:

1. one drop on every chain link
2. leave it for a day
3. wipe down chain

Is the DA cog 3/32 or 1/8?

Teflon is another name for PTFE. Dry lube doesn't last, unfortunately, especially in rainy environments. Try a heavier wet lube, they can get dirtier but last a lot longer.

TriFlow does "wear out" quickly. Have to relube often, IME. It washes out in the rain more quickly than any other lube I've tried. I used to use it when I lived in Phoenix and even in dry-weather-only use I had to wipe down the chain and relube on a weekly-ish basis.

It's 1/8, which was the reason I upgraded 'cause I wanted a full 1/8 drivetrain.
I live in SoCal so it's pretty dry here too, and I was recommended dry lube by my LBS. They said it's good for dry environments. I just bought another bottle too, damn. lol

Would I be better off with wax lube or wet lube?

So your chain is 1/8 as well as your chainwheel?

Wet lubes last the longest.

Yes, 1/8 everything
I'll try using Wet Lube after I get through this 120ml bottle of teflon haha

Up here in wet land I just use TriFlow on brake pivots, derailleur pivots, cables.

Lightweight motor oil on chain. In the winter (actually Nov-Jun) I need to relube chain practically daily.

Today I took apart my BB and repacked it. I decided to go without the bearing cages after reading some forum posts.

However the BB cups still only fit 11 bearings. I read that I'm supposed to be able to fit more bearings without the cages, but when I tried to put an additional bearing in, it didn't fit.

Is there gonna be an advantage in using loose ball bearings over caged? Since it's still the same amount of bearings

There is little inherent advantage and yes, some cages will hold a full complement of 11 bearings. The only advantage to loose balls at that point is easier cleaning if you reuse them.

No, 11 1/4" balls is the most you can fit, retainer or not. Some manufacturers try to save a few pennies by using 9-ball retainers, in which case pitching the retainers and adding more balls makes sense.