do you guys think the reason for my wobbling and tight/loosen chainline while riding is because my cog size is wrong? i think my setup is 1/8 48t, 1/8 KMC chain ( think kmc only make blue chain in 1/8), and 3/32 16t cog (i think 3/32). because when the chain is on the 48t chainring its fitted perfectly and i notice in cog, the chain is not fitted perfectly in the cog, i can wiggle the chain side to side when its in the cog. is it possible that my cog is 3/32? and im planning to get a 17t 1/8 one IF my cog is 3/32 right now. because im sick of getting one skid patch. might as well change but asking first to see if my front IS 48t 1/8 and 1/8 chain.

and would i need a different lockring IF my cog right now is 16t 3/32 to fit a 17t 1/8??
also do you guys prefer 48/17 or 48/15

It's been my understanding that using a mix of 3/32 and 1/8 components was harmless (provided of course it's a 1/8 chain), but w/e. It's more likely that your loose chain tension is caused by something like not tightening your nuts enough, but someone with experience with mixed drivetrains can chime in on that.

You can use the same lockring, that has nothing to do with cog size.

As for 48x17 vs. 48x15, that one's really up to you, but keep in mind that those are two really different ratios. If you find the 48x16 steep at times then going to 48x15 won't be a good idea, and likewise if you find yourself spun out at your current gear the 17t won't be your best bet, although the former scenario is much more likely. Since you mentioned skid patches, it'll be much harder to skid with a 15t cog than with a 17t.

Gear ratio is one of those things that you should really select based on riding conditions and personal preference, not skid patches. If you don't want to change it, your best bet for getting more skid patches would be to go for a 47 or 49 tooth chainring, though that will be more expensive. Again, the 47t will make your ratio slightly lower (but not as much as changing a cog) so I'd err on that side for skidding purposes.

usually if the chain is getting tighter and looser, it's because the chainring is not sitting perfectly centered, which means as it spins, the chain will get tighter and looser.

Check Sheldon Brown's site for how to align it properly.

I doubt is is because of an 1/8" chain on a 3/32" cog. All that will do is wear out the cog faster. More likely it is due some combination of the following: the chainwheel and/or cog aren't completely round (due to wear or poor manufacturing standards); the chainwheel is bent or isn't centered on the crankarm; the crankarm is bent or isn't seated well on the BB spindle.

As for the lockring, it should work on either.

well my bottom bracket is loose, can that add to the issue? and is 48x17 good for daily? use more strength? faster top speed? and easier to skid than 48x16? i hate the one skidpatch on 48x16..

A loose bottom bracket will definitely cause the problem you describe.

No; the most likely cause of a tight/loose chain is an off-center chainring. Sometimes you can reduce this by loosening the chainring bolts and shifting the ring's position a little, but some rings are machined far enough off-center that you'll never entirely eliminate it. This is particularly the case with road chainrings, where concentricity is not a major concern. True track chainrings tend to be manufactured to tighter tolerances and often cost considerably more for that reason.

There is no difference in cog wear regardless of whether you use 1/8" or 3/32" chain.

when my pedal arm side to side, i see my chain flex inwards then i let go of the pedal arm and it goes back to normal