Alright, the backside 50-50.. It's pretty simple. It's approaching a rail/ledge backside, doing an ollie, and landing on it with both trucks and grinding across it. It's sort of a basic grind, but it can be somewhat hard because it's backside. So, I'd suggest learning 50-50s frontside first.
The frontside 50-50 is a lot easier to get into than a backside 50-50. Before trying these, you should get the 50-50 down solid frontside. This way, learning this trick is really just figuring out how to get onto the object backside, and you'll already know the actual grinding and getting off of the object part.
What You May Find Useful:
It can be really awkward feeling getting into a grind from backside. Knowing this, you might want to try some things to get yourself more familiarized with the act. I'd suggest finding a low sidewalk, and just riding parallel with it backside. Once you got that, try to ollie up on to the sidewalk. It's weird, so keep messing with it.
Doing The Trick
Positioning:
The back foot
Nothing weird here. Your back foot should be set up as if you were going to do an ollie.
The front foot
Again, nothing out of the usual here, either. Set up like you would for an ollie, but make sure you keep it in a location where you can level the board out easily. I'd say set up as if you were just gonna do a frontside 50-50.
Motion:
Alright, remember, this is just a 50-50 grind. As I said earlier, you need to already have a solid frontside 50-50 learned before trying this one. Assuming you do, you will want to approach this like you would for a frontside 50-50, except approach it backside.
The weirdest thing will likely be judging your distance. It's a lot harder to do when the object is behind you and you can't easily spot your landing on said object. But all the same, you have to focus on the object you're going to grind on at all times. But hey, let's get this part started, ye?
Set your feet up as explained above. Approach the object you want to grind with proper speed and judgment (if you have a hard time determining this, refer to frontside 50-50 trick tip)
When you're at the right distance, pop your tail and begin your ollie
Okay, time for the weird stuff. You have to guide your board over the rail. You will do this with your entire body, making sure you stay over your board at all times. You really can't spot your landing easily, so you kind of have to just know where you're going to land and commit.
Land with both trucks on the rail evenly, and focus on staying over your board. Keep it balanced like you would with a frontside 50-50, and ride it out.
As you approach the end of the object you're grinding, you need to get ready to get off it. This shouldn't be anything new to you, though. The simple putting a bit of pressure on the tail and keeping your board leveled out as you leave your object.
Land on the ground with your feet on the bolts and absorb impact appropriately. Ride away clean. Good job!
Video Trick Tips:
Troubleshooting
Okay, weird trick is going to result in problems, no doubt. If you have a hard time with this trick, check below.
I can't get onto the rail/ledge to grind. I miss it, as in my trucks don't land on it!
This is probably going to be your biggest problem with this trick. More often than not though, it's not working out simply because you're not committing completely. It's easy to sort of try to bail when you're not able to spot exactly where you're going to be landing. But you just have to push yourself and make it happen. You might not see it, but you KNOW where that rail/ledge is. Nobody is gonna push it out from under ya when you're not looking.
But if you're trying as hard as you can, and it's still not working, don't stress it too much. I'd suggest going and practicing my 'sidewalk' method I mentioned above. Or, simply take a piece of chalk and draw a line on the ground. Approach the line backside and pretend it's a rail. Ollie up and try to guide your board over it and onto it. After a few tries you'll see how you need to guide yourself, and find it's not that hard. Now, just apply it to an actual object!
As soon as I get on my rail/ledge, my board slips off
This can be happening for a few reasons. One being (this is likely the problem you are having) is that you're not landing leveled on your trucks. You really have to have them as centered as possible. If you land with too much of your trucks hanging off to any specific side, you're going to apply too much weight to said side, and it's gonna make you fall off.
If you feel that's not in fact the problem, focus that when you're grinding you stay completely over your board and the object you're grinding. Leaning too far to any side of the object will have you falling off. With this in mind, you will likely find this trick easier to learn and practice on a ledge rather than a rail, as it's easier to balance on.
I get into it fine, and I grind it out, I just have a hard time getting off the rail/ledge
Don't let this happen to you. You should already know how to correct this, but just in case you need your memory refreshed, as you reach the end of the object, place a little bit more weight on your tail. Just enough to keep your board leveled as you leave the object. It's very similar to simply riding off a ledge.
Hopefully that can clear up any problems you encounter. And you have to keep in mind.. This trick isn't terribly technical or difficult on it's own. So, don't make it harder than it should be in your head. It's weird, as I've said a million times now, but you just gotta commit. After a while, you'll break that "weird" barrier, and find yourself saying "man, that trick is so easy!"
Where Do I Go From Here?
Higher objects, faster grinds, and a cleaner style. Remember, skateboard is all you make it to be. It's what you want it to be. So, take this wherever you want. Good luck!