Symptoms of a maladjusted final drive chain?

[maximusrising]

And/or spent chain?

All of a sudden I’m gettting a rrr rrr rrr feel-it-in-the-foot pegs on decel/coasting
It’s audible and sounds like “chain lash” which is a term I made up I think but hopefully conveys. Like the chain is all of a sudden rubbing on something
Pulls strong going fast and accel

 

[Downeaster]

Probably lube or adjustment.

Lube is pretty much like oil: Everybody has an opinion. As long as the chain isn't dry/rusty you should be good.

I've always used 3/4 to 1 inch of play in the center of the bottom run of the chain with just the weight of the bike on the suspension.

If both of those items are okay, look for kinks in the chain indicating a damaged link. Examine the sprockets for damage/wear on the teeth. Make sure the sprockets are tight and not flopping around.

 

[DogBunny]

Worn-out chain? I've seen chains where you adjust the tension at the tight spot, and the chain is still floppily crazy-loose at the loose spot.

 

[gggGary]

hooked front sprocket teeth from severe wear will do that.

removed from a bike I bought. If the chain skips a tooth it can crack the crankcase.