So I’m reading some entries on plasticsdb.com, and some of them say things like: right spin only, which doesn’t really make any sense to me, since I could just use them with an L spin launcher? Why do spin gears have stickers that say ‘right’ or ‘left’ when you can spin them however you want? 
https://www.plasticsdb.com/beyblades/met...ng-stinger

Spin gears are right only OR left only. No spin gear is both left and right except for Gyro Base which is an incredibly special case.

Spin gears are right only OR left only. No spin gear is both left and right except for Gyro Base which is an incredibly special case.

Okay but again, how does that work? Take Driger F for example. The ‘right’ spin gear itself is just a metal rod. There’s no independent spinning mechanism like engine gears in it. What’s stopping me from just using the beyblade with a left launcher?

the tip is not the spin gear. the spin gear is the little block of plastic the attack ring locks onto and is what determines the spin direction of the beyblade. it would be more correct to call it a spin gear casing. In the casr of driger F, the spin gear casing is unique to that base, and no other spin gear casing can fit into that base, locking it to right spin. but the metal shaft can be put into other spin gears and used on other bases, allowing the shaft to be dual spin.

the tip is not the spin gear. the spin gear is the little block of plastic the attack ring locks onto and is what determines the spin direction of the beyblade. it would be more correct to call it a spin gear casing. In the casr of driger F, the spin gear casing is unique to that base, and no other spin gear casing can fit into that base, locking it to right spin. but the metal shaft can be put into other spin gears and used on other bases, allowing the shaft to be dual spin.

And what exactly makes that SG casing left or right spin?

The placement and size of the little wings the launcher hooks onto.

You can see it if you compare an R spin gear case to an L one. Links to both below

Left spin casing:
https://www.plasticsdb.com/parts/spin-ge...ear-shells

Right spin casing:
https://www.plasticsdb.com/parts/spin-ge...ear-shells

Ah gotcha, I see now. Thanks