I always thought its for approach angles? Lets say a stock jeep with stock bump gets hung up in a snow bank or rock, now lets try again with a stock jeep but with a stubby bumper, can it go up and not get stuck?

 

Clearance as well as departure/approach angles (some models) and the by product, less weight. Thirdly, aesthetics.

 

The way you asked your question was a bit confusing but I think this will help you.

Full width bumper is typically preferred by over landers because it pushes bushes, etc out of the way.
Stubby bumpers help with rock crawling, with a single rock you can put a tire up on it and crawl up a steeper angle because now the tire size is the only thing that affects what you can roll up.

For snow and deep mud it is all about how much you sink or have to plow. So ground clearance and proper tire choice for the surface is what need.

Approach angle is about the angle you have to crawl up from your current angle. Stubby versus full width (all other factors the same) won't affect this if you attack straight on, stubby helps if you take it at an angle. How much the bumper sticks out from your jeep is the big determiner for approach angle. Some full width bumpers stick out less than some stubby bumpers (brand vs brand) and they will have better approach angles. Hope that helps you.

 

As you can see in the picture, there can be a full width bumper which gives a pretty good approach angle for the front wheel, without giving up added protection at the corner.
In this case, it's the SmittyBilt XRC.

 

For me, it was an interference issue. My tire was hitting the bumper at full turn. But, I streched my front axle 2 inches and am running 38s.

 

Your photo doesn't show approach angle. You need to see it from the side. Approach angle is effected by how far out the lower point on the bumper is. The angle is contact patch of your tire to this lower point on the bumper. This image from Shrockworks shows a bumper with a good approach angle. They don't make a full width, only mid-width.

 

I know what an approach angle is, buddy... and you can easily asses the angle -- because you see how narrow the edge of the bumper is, and where it is, right under the front of the flare.
I marked the front view of the steep angle of the bumper corner, because this specific photograph isn't of very good quality.
Tomorrow, I'll try to add a side view pic...

 

Yea but some bumpers like the one I'm running require you to cut a few inches of the frame to increase the approach angle even more. I'm running the poison spyder bfh trail stinger

 

I run a stubby for the reasons above, plus it is much easier to remove and install the swaybar links compared to when I had full length stock bumpers.

 

Of course you do. But this subforum, and this thread in particular, are directed at people who may not. A bit more explanation might prevent confusing someone.