Chain falling off into the gap between the rear sprocket and the spokes

The above was exhilarating but not something I want to experience again.

I'd let my chain get a little bit slack but I didn't think it was that bad at the time. The chain line looks good to my eye but what I'm wondering is does the direction a chain comes off the sprocket tell you anything about the chainline? ie if it comes off to the right (away from the wheel) you might benefit from a spacer at the back?

No. You need more unchaining events to achieve statistical significance. Maybe this time the unchaining was caused by a fly impacting from the Drive side, which might be covering any chainline effect. More data please, maybe 10-20 events would be good.

Down a hill would be easiest.

Is it a road conversion?

Maybe check here: https://www.lfgss.com/conversations/130300/

First thing I would do is check your derailleur, it might be pulling it too far and making the chain come off. It's essentially a chain guide so I would go there first of all.

Wtf is a derailleur?

It's something that can't be fixed, and if you have one you're doomed.

Since the OP accepted responsibility for slackness, presumably it hadn't already been delegated to a derailleur.

yes, it's fixed gear. I took the sprocket off and put a spacer on, I couldn't tell if made the chain line any different, it still looks good to me. I have had the same crankset, bottom bracket and rear hub for many years with no problems including many times riding where I'd let it get slack. I recently changed to a much larger chainring and sprocket, I don't know if that's got anything to do with it.

And thank you for the comedy gold above. Hopefully you guys will experience something similar in the near future so we'll have an opportunity for more laughs together!

Hopefully you guys will experience something similar in the near future so we'll have an opportunity for more laughs together!

Ooh, and we're onto the mild curses. :)

#youdon'tknowwhatyoustarted

I'm just glad, by the way, that this thread wasn't about the chain falling off into the gap between the front sprocket and the frame.

why is that worse?

Always ride with one of these in my jersey pocket

The efficiency gains outweigh the weight, I can send over the calcs

why is that worse?

You don't want anything to happen to the front sprocket.

Sorry my bad. forgot where I was...