there’s alot of things to process and things are done different ways and called different things.
as far as i know Gravity or Gravity assisted is just what they call Downhill pretty much anywhere besides the states. I also know its call gravity in the latin countries where they get all suited up in aerodynamic leathers and go a million miles an hour down the side of a volcano haha. The one I found interesting and they do it at NATS at Deer Valley and i’m sure all over are the down hill Chainless races where that really take the chain off and its nothing but gravity getting you there.
as far as XC goes i’m not so sure I know the longer races are called Enduros or Marathons but its pretty much XC riding. Theres also the Super D which is a mix of XC and DH and which is usually the fun run for everyone.
Freeride is a little weird. Its more a test of skill and style. the corses have cliffs , ramps, crazy jumps whatever they want to throw at these crazy guys. the Objective is pretty much to get down the hill smoothly or at the very least in one piece. I think the route you pick to get down is pretty critical to points and sometimes they may be timed but I think its usually about style and how easily you can get down.
4x, I think the call it moutaincross abroad. Is quite similar to BMX or motorcross. It starts with four riders (thus the 4x) and they start at a gate like BMX and race through a track i’ve heard of it head to head but i think its usually one rider at a time and they time it the fastest one wins obviously and like BMX or MX they top half of each moto (or heat) moves on until there’s on man standing.
Hope that helps and I hope someone will correct me if any of this is wrong.
now lets hit the trails!