every once in awhile my freewheel skips under load. would this be a symptom of sticky freewheel pawls, or perhaps an under tensioned chain? chain is new, freewheel is stock from an 08 bike but the teeth aren't looking too sharky. think a mega blast of wd-40 is a good start?

I'd measure chain "stretch".

New chain with worn cog = skip.

yeah, thats what i was thinking now that ive thought about it a bit. ive never changed a sinlge speed freewheel but i picked up the removal tool so we shall se how it goes. its probably more worn then i think too. its been through three oregon winters and its stock so i guess well just say adios!

Many single speed freewheels are pretty low cost in their construction. I had a trials guy (all 125lbs of him) working for me a while back. He would go through a number of these every season. Not from tooth wear but from ratchet skipping. After taking the first few apart to confirm this he just bought a bunch at a time and he was good for the year. His chains would last a couple seasons if they didn't get ground down from his wall work. Andy.

If the bike doesn't have some kind of a chain tensioner, I'd suspect the freewheel ratchet as well.

Yes, if the chain is a simple loop without a tensioner or derailleur below, then the chain is ruled out. The chain simply isn't long enough to climb over the top and slip. SS bikes can drive even if all the teeth are worn to stubs.

I't is nearly impossible to get a actual chain skip on basic setup SS/FG bike. While if you ride hard checking the chain and front chainring sprocket and BB are not bad idea's. You problem is likely the result of a sheaper freewheel riden hard simp fix you can buy decent new freewheel for about $15.

The freewheel pawls are hardened steel and can be a bit brittle. Skipping under load is a symptom that the pawls may have developed a bit of chipping on the face that engages with the freewheel body. Hammering into power mode from freewheeling may cause this; however the skipping then re-engaging is likely to do more damage.

Skipping under load is worrisome and potentially dangerous. It always gets worse.

OP again. yeah, i was at a stop light when it skipped and i lurched forward. didnt wipe out but you are right, it was only getting worse. i erred on the side of caution and chucked it. installed a shimano one from western bike works down the street. intrigued by the white industries rebuildable one though. it looked niiiice. $$$ though. how important is chain tension in the grand scheme of things? i dont have tensioners on the drop out but the top of the chain seems taut with no sag.

It doesn't need to be tight. A little slack helps the bearings move freely, and an overly-tight chain can cause premature wear.

Actually, this isn't strong enough. I needs slack at all times. Since sprockets are eccentric a tight chain can bend axles since it has no give. The ideal "tension" is no tension, with a bit of slack in the tightest position of the eccentric sprockets.

OTOH- if there's any tension as the chain runs (not counting driving tension in the upper loop), the chain will wear faster and establish the slack it needs in short order -- hopefully not by bending the axle.

new freewheel new chain 'teeth not to sharky' indicates it's worn none the less , replace both together .

chainring wear also in question .. get all 3. change the gear ratio at the same time with the tooth count selection.

so whats a folky way of checking chain tension? like the equivalent of plucking spokes? im not yanking on the wheel extremely tight when its in the drop outs. im just aligning it and then pulling tight enough for there to be no sag in the top of the chain line. if i bounce the wheel the chain dips down and then back into place. thats good enough right? i see some dude rolling around town with a really droopy chains, but they usually look like scruffy hipsters on beat up peugeot conversions...

yeah, i have not addressed the chain ring yet. steps 1 and 2, chain and rear cog, replaced. heh, sharky....thats technical speak....

I get behind the rear sprocket and sight down the chain while I spin the crank... right or wrong, I want to see at least a tiny amount of droop throughout the crank rotation.

There's no issue with an overly slack chain, as long as it doesn't derail. Since you're not setting tension, but slack an eyeball or touch measurement is all that's needed. Turn the cranks, find the tightest place, and set the slack so that either loop can be deflected up or down about 1/8" at the middle -- not by stretching, but freely.

On a fixed wheel, it's possible to use an alternate method that I prefer because it allows me to work very close to zero slack. Find the tightest spot by pedaling slowly with a finger below the middle. Once you have it you can pull the wheel back until the chain pulls up tight, then ease up a hair and tighten the nuts. Check by noting that there's a bit of vestigial slack that allows some backlash at the crank when the wheel is stationary.