How to build DH/freeride jumps?

[trouble]

Hey everyone,I've searched but still haven't seen what I am looking for. I am looking at building some downhill/freeride jumps decently large. Some good examples of these are from this video,
http://www.youtube.com/watch?v=gloeXuBQFPY
I'm just wondering cause I've seen some which have nothing under them,as if they used plywood with dirt ontop with logs on the side?

Oppinions, help is greatly appreciated,thanks,BEn

[thompo]

well heres your DH

http://forums.farkin.net/showthread.php?t=56819&highlight=build+dirt+jumps

and here is your DJ

http://forums.farkin.net/showthread.php?t=56509&highlight=build+dirt+jumps

(might help if you search on farkin using words such as how to's + what you want, although common words aren't included)

[pinned--->]

For most of ours we find two tree's and put a door behind them and just pile dirt infront of the door, And for the downramp just make a massive pile of dirt and compact it down the way you want it.

[LyonsDJmetalheaD]

http://www.youtube.com/watch?v=gloeXuBQFPY

Best DH/Freeride video i have seen in my life so far.
And I have seen Roam and most NWD.

My advice is to keep the the track flowing.
Make sure you have time to posistion yourself before and after landing then start to gain more speed.
Momentum is a key factor. You want to gain momentum and keep it flowing.
No abrupt turns after jumping.

[Stack Shack]

I make my downhill jumps really mellow (sp?). Not to steep with a long down ramp. once i get the camera working ill post some pis. Also, how steep is this track. If possible post pics

[cuts and bones will heal]

Not to steep with a long down ramp.

^^^^That would probably be the best idea.
The angle/curve and size of the kicker is almost completely dependant on the speed of the run in and the size of the chosen area (rider skill is another factor, but thats really up to you). For example: if the site of the jump has a lot of speed coming into it, its best to make the slope of the kicker a very gradual one. If the kicker is too steep for the speed your likely to be bucked off the bike, which is going to hurt when you come down. As you would expect, a gradual kicker will give you less air time and probably more distance, than a jump with a steep kicker which gives you the opposite effect.

The size of the area gives an indication of the size of the jump i.e. a large jump needs a large area, because your going to be going further and building bigger. Freeride/downhill jumps are usually aimed at distance over height, where dirt jumps (as in trails) are usually designed for height for tricks.

The down ramp is simple: long and gradual (this give you a good margin for miscalculations...). It will pretty much work for any kind of kicker (unless you building some kind of freeride pump-track... :rolleyes:).

A very important thing to keep in mind if they are being built on a DH track (and/or are going to be under heavy use) is how they will fare over time, will they wear down quickly? are you prepaired to maintain them? etc.

As you pointed out, the jumps in the video are simply a box of wood, that is filled with dirt, for both the kicker and the landing. This just means they didn't have enough dirt in the area to make a completly dirt landing or thought that having the box would make it quicker and last longer. The catch to the wooden box (and wooden landings in general) is the cost of the wood and any other materials needed. But if you can afford it, its a great way to save time, and dirt. NSMB (http://www.nsmb.com/) has a shitload of examples of this (go into the photo gallary section).

Most of it seems like common sense and its longer than originally intended, but i hope it all helps anyway.

[simon rocks]

wheres that track at, its awesome.