Recently my chain has been coming off a lot when I have a lot of momentum and try to skip/skid stop.
I've tightened the chain up some and it's still occurring.

Any clues why this is happening and what can be done to fix it?
Do I need a better chain or chainring or fixed cog?

Thanks.

Tighten the chain some more and crank down the bolts to make sure it doesn't move and you should be good.

Primarily, this can be caused by two things:

1. your chain being too loose. research proper fixed gear chain tension and do it.
2. your chainline being way off. The less straight your chain is, the more likely it is to come off. If your chainline is off by a lot, you'll probably need to get new components if you want to fix it. One thing you can possibly do is move your chainring from the inside to the outside of the crank arm or the other way around. You can research more about this if you suspect a misaligned chain.

If it's tight & jumping, then odds are it's not straight. Next bet would be a well damaged link, or tooth.

another possible solution is scooting the hub back creating more tension in the chain. farther back the better

Help us understand what you are working with:

Bike model?
Frame material?
Bike size?
Track or conversion?
Type of Hub?
Type of Cranks?
Type of Bottom bracket?

sounds scary...it must be your chainline
perhaps you need to check where your chain ring is mounted and also check your spacers on the hub...bottom bracket spindle length is important too

How old are your chain and cogs? Even fairly loose chains should require unusual circumstances to jump off. If your chain and/or cogs are worn or mismatched they have a better chance of misbehaving.

i had this problem when i was not running the same widths on my cog and chainring... it would pop off in similar situations... check this.

This sounds very dangerous. If you really have to ask, you should walk, not ride, to you nearest LBS and have them solve the problem.

This happened to me when I first built up my conversion. What happened was that I was running a 13 tooth cog and my lockring was too tall, keeping the chain from sitting all the way into the divits of the cog. Pretty slim chance that the same thing is happening to you, but check it out.

- Definitely tighten your chain, but not too tight. You should be able to move it up and down at least a centimeter at it's loosest point.

-Tighten your chainring bolts. If a few of them are loose, then your chainring could wobble side to side, causing chain to fall off.

-Tighten your cog/lockring. I don't know how this could create a chain jump, but just do it anyways.

Specs:
56cm Kabuki conversion
165mm Sugino RD cranks
108mm Triumativ BB
18tooth generic cog
48tooth generic chainring
Formula hubs

Chainline is pretty straight so I dont think that's it. Cog and chainring are about a year old. Chainring is mounted on the inside.

must be those darned rd cranks...just kidding
it could be your old chain ring and cog...look at the teeth do they look like sharkfins?
where does the chain sit on the teeth as well? perhaps the chain is old and worn

Pretty strait doesn't tell us much.....

Actually take measurements. There's no other way to know how many mm your chainline is off.

pictures pleez

Measure your chain for stretch.

I would venture to guess that your rear triangle is flexing/twisting under stress which changes the angle of the wheel and ultimately the cog thus throwing the chainline off.

I had this problem when I 1st converted my bike. It was due to a very worn chainring.

Also upgrading from 3/32 to 1/8 inch chain/chainring/cog seemed to help in my case.

Here are a few pics.
Thanks for the replies!