I've suddenly got a rhythmic sound when I pedal, sounds like rubbing or grinding. No sound when I coast. It takes a couple minutes when I first get on the bike for the sound to manifest. Happens on the flats when spinning in all gears. Bike is only 3 months old (Bike Friday NWT, Velocity rims and hubs, Sugino cranks).

Things i've done:
regreased both pedals
lubed chain (squirt lube)
reseated front and rear wheel in dropouts
checked tightness of crank bolts
retightened both seat mast and stem mast
checked brake pad clearance

The only wear I see is on the inside of the chain guard - where the chain rubs when on the smallest cog; the chainline in that position isn't perfect. If I know what it is I am sure I can fix it, but I have a really hard time figuring out where noises are coming from. Any ideas on what else to check would be most helpful; otherwise I'll head over to the shop.

Edited to add: I did lay the bike down on the non-drive side in a little fall not long before the noise started. Other than some scratches to quick releases I did not see any visible damage. I don't know if it's related.

Shoe rubbing on a crank arm?

Tinnitus , in my case..

Wish it was that simple, lol. I learned a long time ago to tie my laces under the cross pattern after I spent forever tracking a noise that turned out to be the end of a lace whipping the frame!

Still could be a shoe rubbing. Places I've seen are the sole and at the balls of my feet. Look for some polishing of the crank arm.

Ben

Do you get the noise when you're out of the saddle?

You have not indicated whether the noise is in time with crank rotation, but I assume it is. If you think about it that already eliminates brakes/wheels, rear cog/hub and chain, because the wheels only rotate in time with cranks on a 1:1 gear, and the chain never does. Check out of the saddle to eliminate seat/post, but a more sustained sound rub/grind is far more likely to be between two moving parts, such as within the BB or pedal bearings, than between parts that are not meant to move.

I'm going to pull the hinge pin today and clean and regrease it. While it seems awfully soon (3 months), the pakiT is folded multiple times each day so maybe it requires a bit more tlc than the hinge pin on my NWT. It definitely sounds like metal on metal rubbing that flexes with each stroke. It does not happen out of the saddle, I don't think, but it is really hard to pedal out of the saddle on the pakiT for a sustained period. Will let you know if it is the hinge pin.

Although it could be something you could diagnose and fix yourself I'd say take it to the shop you bought it from. Should be under warrantee and you could void this if you start fiddling around with some parts. Also be up front about your fall which adds to your own credibility and may help the mechanic find the problem if that's what caused it.

I once had a rythmic thumping sound evertime the crank arm came 'round.
Below a certin speed, there was no need.
It drove me batty until I noticed the shoelace went slappy.
I retied the lace and switched up the pace.
Now my riding is savvy.

It was the hinge pin - problem solved. Thanks for all the input.