FrenchFit 

80's bike, Araya A20 rims running different sets of 700 x 25..

Weird noise, sort of like spokes resetting, but much quieter. I checked the spokes, repacked the front hub, switched to a different tube/tire combo, but there remains this light tinkling sound coming from the front of the bike. I repacked the headset a few years ago, but that's all that's left that I can think of trying. Under weight only, not speed dependent, no particular cadence...just random.

I speculated it might be new tires throwing up tiny debris into the frame, but it was just the same with well used different slick tires, and change in speed or surface doesn't matter.

I road the bike hard on the flats a few weeks ago, handled everything just fine but all of a sudden it starts makes this odd tinkling noise.

Anyone solve a similar mystery sound? As I write this I am wondering if I have a fissure crack in the rim somewhere....

HillRider

Valve stem rattling against it's hole in the rim?

79pmooney

First, is it a hollow rim? (The Araya's I remember weren't but few were in those days.) By hollow, I mean - do the spokes sit below the tire and tube so you have to reach in with a tool do anything with them from the tire side or are the heads immediately beneath the inner tube, separated only by the rm strip?

If it is hollow, take the tire off and the rim strip. See if there is anything loose in that hollow section, If there is, you should be able to coax it to near enough to an access hole to grab it with tweezers. I have had spoke nipples break and the tops rattle in there. (That's almost always from spokes that are too short.)

Ben

Edit: before you do this, but a new rim strip the same width as your current one. Unless it is a Veloz strip, you may well destroy it taking it off and even an old enough Velox will suffer.

Andrew R Stewart 

+1 on 79's suggestion. While not an issue with alloy rims I've seen more then one steel rim with rust particles making a showering sound. Have you tried a different wheel yet? Andy

FrenchFit 

Love these suggestions, I'll inspect the inside of the spokes seats this weekend and try a different front wheel...of course..

HillRider

I have a Mavic CXP-33 rim (double wall alloy rim) with a fragment of metal, probably from when the spoke holes were drilled or punched, that's caught between the walls and can be heard rattling at low speed. It's not audible when the bike is moving at any real speed. Several attempts to find and remove it have been unsuccessful and, after 36,000 miles, I've learned to ignore it.

Andrew R Stewart 

This is likely the rim's joint plug that's broken loose. Many Mavic rims have this noise. Not quite the same as might be plaguing the OP but an object in the rim just the same. Some have driven self taping screws or dripped glues into these mavic rims to quiet the plugs. Andy

HillRider

I'm pretty sure this rim has a welded seam since the sidewalls/brake tracks were machined so AFAIK there aren't any alignment dowels.

Litespeedlouie

Another thought: I once had a steel fork that had some small brazing globules get loose inside the fork blades. Road vibration would jiggle them inside the fork, causing the noise. I squirted some super glue into the brazing vent hole and shook the (removed) fork around.

Darth Lefty 

I thought welded rims still have a biscuit (or whatever is the term of art)

CroMo Mike 

I had a piece of something rolling inside the tube of a tubular tire. Tick, tick, tick. I tried some tire sealer to "glue" it in place, but it soon got loose again. When the tire was finally shot I cut it open to see what it was. Turned out to be a small brass fragment that looked to be left over from the process of making the valve stem.

FrenchFit 

Found it.

Ultra fine monofilament line wrapped around the hub at the back/inside of the freewheel.`I guess the sound transferred up the tubes and drivetrain, but switching wheels was the right first step. Repacked the rear wheel while I was there, a good use of time.

Unbelievable it could make that much noise, but live and learn.