I'm building a brand new Bareknuckle from almost all new components, which includes the following...
Sugino 75 cranks with Sugino Zen 49 tooth 1/8 chainring
Shimano 110 mm bb
Izumi track chain (1/8)
Surly fixed/fixed hub.
Surly 15 tooth cog on the flip side (slightly used, but not visibly worn), and a new EAI 16 tooth cog on the flop side. Both are 1/8 width.

The chain line is not measurably different from perfect, yet the chain makes this horrible grinding noise when I pedal. Its so bad that it feels and sounds like the chainring is literally grinding against the chainstay. However, this is not whats happening. The problem is clearly with the chain and cog. When I flip the bike upside down and pedal, I can see the chain trying to ride up on top of the teeth of the cog. It happens with the chain too loose and also when the chain is tensioned properly. When the chain is really tight the chain obviously doesn't have enough slack to ride up on the teeth, but the grinding sound persists anyway. The harder and faster I pedal, the louder and rougher it gets. The problem is so extreme with the Surly cog that the bike is basically unridable. WIth the EAI cog on the other side of the hub, the drive train is slighly smoother, but still way too loud and rough to translate into an enjoyable riding experience. This just doesn't really make sense to me. These parts should all be compatable. I've looked the chain and cogs over, and nothing seems to be wrong with any of the parts. I've used the same surly cog on another bike that has a cheaper KMC BMX chain and it is much smoother. I just can't figure out why the Izumi chain is so incredibly loud and rough, particulalry with the Surly cog. Any ideas?

Have you lubed your chain? Did you grease the threads on the BB before you installed it?

Usually when a chain rides up on the teeth it's because the chain is stretched. Your post implies that your chain is new, although you don't really say that explicitly...

Did you eyeball your chainline, or actually use calipers?

The chain has tons of factory lube on it. And the BB is installed properly and spins smoothly.

I'm pretty sure the Sugino 75 bb has a spindle length of 109. That would throw your chainline off by 1mm. Not a big difference but might count for something.

Chain is new...chainline is off by no more than 1mm according to my calipers.
also, I measured the chain and 12 links = 12 inches, so it is not stretched.

that would throw it off by 0.5 mm, not 1 mm. Moreover, I could be wrong but I think the chainline of the surly hub is 42.5 mm, which would go perfect with the 110mm BB. At any rate, I've measured the chainline and its less than 1mm off. To put it another way, the chainline is close enough to perfect that my calipers and metric tape measure can't detect a chainline different from perfect.

Sorry, I don't follow. Why 0.5mm? Do you mean because of your hub spacing? Because a spindle which is 1mm longer should move the cranks out 1mm right?


Oh never mind then. Maybe give it a few days to break-in, maybe it's because the chainring is brand new.

A lot of the time that 'factory lube' is anti-corrosive grease that picks up dirt like no-one's business. New chains should be soaked in degreaser, scrubbed, then properly lubed before usage...

If a spindle is 1mm longer, that would throw the cranks out 0.5 mm on each side, assuming that the spindle is symmetrical. Maybe, I'm wrong..the spindle is not symetrical and the added 1mm length is only on the drive side of the spindle. i'd be interested in knowing which is the case. At any rate, its got nothing to do with my present problem.

agreed, but it shouldn't make a brand new (clean) chain run rough.

Im not going to be much help but I, as well, have noise issues with my bareknuckle and izumi chain. chainline is good too. coinsidense but still i know how you feel

heres another observation...
If I spin the cranks really slow, as each roller of the chain engages with the cog, I can see each of the rollers sort of abruptly popping down between the cog teeth of the cog, or snapping into place. Its almost as if the teeth of the cog are too wide to accomodate the diameter of the chain roller.

what cog are you using??

Right. Makes sense. I missed that one. (smacks forehead)

Sounds like either your chainring or cog or chain may not actually be 1/8", have you verified this?

When I was running my brand new chain on my Lejeune, I didn't lube it because it was factory lubed. My drivetrain was pretty noisy mainly because I was using road cranks BUT... When I properly lubed the chain it made my drivetrain a LOT quieter. Couldn't hurt to try.

its a soma cog with a formula hub

Yes...every part of my drivetrain is 1/8".

since it changes when you flip the hub, maybe the chainline isn't right
(the cogs give slightly different chainlines, they are different thicknesses)

how are you measuring your chainline ??

for a pretty darn accurate measurement
half the rear spacing - the distance from inside of rear dropout to the face of the cog - half the width of the cog
should equal
the distance from the edge of the seat tube to the face of the chainring + half the width of the chainring + half the width of the seat tube

also, maybe your chainring is not perfectly round, or not installed with the bolts tightened down evenly ?

Sorry, but I don't see how this makes any sense. Road cranks versus track cranks should have nothing to do with noise as long as your chainline is straight. The noise my chain is making has nothing to do with lube...the chain has plenty of lube. Its an intense grinding noise caused by the chain not engaging the teeth of the cog properly and the grating rough effect that it makes is beyond noisy...its downright unridable. You could probably hear it clacking a block away.

The chainline is straight to within a millimeter...I've measured it over and over, on both sides, using the method you just described.
As for the chainring being round...I'm pretty sure it is. There are no tight spots in the chain, and the bolts are all tightened propery. The chainring spins straight and truem, and the chain engages with it smoothly. The griding effect pretty clearly is coming from the cog, not the chainring, so I don't think the chainring is the source of the problem.

If the chainring is true, and it happens on 2 different cogs:
Use real lube on the chain. You've obviously eliminated everything else. That packaging lube is thick and if it's cold out it can gum up.
If it doesn't work, measure the chain and return it.

yeah...i think its gonna come down to returning the chain. The grinding is so bad that its way beyond a lube issue. I mean, despite any nit picking about which lube is ultimately better, there is plenty of lube on there and the chain is plenty slicked up. A completely unlubed rusty chain should run better than this. Its not a temp issue either. Its only 55 degrees out and the problem persists inside my apartment and outside. Despite the fact that the chain and surly cog are 1/8 inch, it just looks to me like the surly cog is too thick and burly to easily accomodate the Izumi chain, which is also pretty thick and burly. The EAI cog (also 1/8 inch) is slighly thinner than the surly cog and accomodates the chain a little better, but not nearly to my satisfaction. In the past I've had better luck with higher end (~$20) KMC BMX chains. I'll probalby go back to that and see how it works out. Thanks for all the suggestions guys...

how does an 1/8" chain work on an 1/8" chainring but not on 1/8" cogs ??

weird