What's your minimum Karma obligation to other bikers?

I always ask. ALWAYS.

I ask if they are ok or if they need anything.

Comet's right on. 

I've also loaned tubes, levers and CO₂ cylinders on occasion.  What goes around comes around.  Plus it's good way to make new friends.

Mark

I ask how much it's worth to them for me to help...$$$$$

LMAO!!  Sometimes I amuse myself.

Vonrunner, if you have Aerobars on, I have found that generally you won't get too much of a wave back from Roadies.  But other Triathlete's will wave back.  That's what I've found.  I've been accused of being too friendly too.  I get laughed at a lot because I wave at everyone and their brother that is riding the other way.

I always ask when I ride by.  I don't care if there a gaggle of other riders there.  It can't hurt to ask.  If I've got it, it's yours.  I also hope if I'm on the other end, I'll get asked as well.

I gotta echo what was said earlier. If you're on your tribike on the side of the road and a group of roadies goes by, you probably won't dignify much of a response from them as you are merely a "triathlete", spreading your time between three disciplines instead of just riding your inpronouncable italian road bike.

But, if you are on the side of the road with your road bike, fellow purist! To the rescue they will come.

So do what I do. Always ask if they need help, and do what you can. If they don't offer help to you (roadies), fine, fix your damn tire, hammer up the road, and pass their pretty little peleton with your freaky handlebars! That is the best type of revenge out there.