jump face dimensions ? plz help

[bully_23]

Ok I'm new to the whole track building thing and have currently got a sort of track that includes 1 berm 3 small ski jumps 4 whoops and a tabletop.
I have decided to build more of a track and add more obstacles and alter existing ones and incleude more corners turns and berms. I took the measuring tape out after I learned from doing a search that the jump face should be 2.5 - 3 times longer than the height of the jump. This was helpful information however I would like to know how tall a jump should be for the length of it. you see at the moment I have a 3' 7-8ish" high tabletop, the jump face is only 7' long So I know I need to make that a bit longer but I also need to make it higher also. At the moment the distance from the top of the face to the bottom of the down ramp is about 50" So as you can imagine I need a lot of speed to clear it and I know that the height being under 4ft isnt right. There is massive gaps in my track at present so this is not such a problem but when i add more obstacles and corners I will not have as much of a run-up therefore would like to know the appropriate height of a 50' table. also what sort of an angle should it be i assume a fairly slight angle with a gradual build up on the face?
Thanks in advance

 

[FruDaddy]

I have seen a 42 foot table that was less than 3' tall. I also frequent a track containing a 60' table that is in the 6' height range. You can clear 50' from a 4' high launch if you hit it hard enough. The slope of the ramp is more important than the height.

 

[bully_23]

what should be the angle of the slope then?

 

[Jaybird]

http://www.racingsmarter.com/supercross_track.htm

 

[FruDaddy]

For amateurs, usually 3-4:1. For a 4 foot high jump, you would begin the ascent 12-16 feet before the peak. The faster you hit it, the farther you will go, but the light angle of the slope will keep you close to the ground. Steeper slopes will send you higher, and bring you down harder, but you could still make the distance.

 

[just_a_rider]

2:1 ratio for pro class jumps like you see in supercross, amateur jumps are usually on an 3:1 ratio. For every foot high your jump is you go out 2 foot for the pro class and 3' for every foot high for amat. You can mixem up if you want, say you need some distance to clear an obstacle that you just can't get out of a 3:1 ratio on ramp. Use a 2:1 or a 2 1/2:1 for the on ramp and 3:1 for the in betweens and off ramps to allow for mistakes or even a 4:1 to be real safe until you learn more.

 

[just_a_rider]

I've recently torn my track down and have sown grass back. Hated to do it but is was on one side of my drive in the front yard and the wife wasn't to crazy about it, yes I have a huge front yard :coocoo:
I have built all kinda jumps on diferent ratios but I have to say that the 2 1/2:1 on ramp is my favorite.
For tables the off ramp is determend by the length of the top, 50' length = 100' off ramp or something like that.

 

[sixds]

post pics of your home made track. im in the middle of building one myself.

 

[FruDaddy]

For tables the off ramp is determend by the length of the top, 50' length = 100' off ramp or something like that.

When you speak of off ramps, are you referring to the landing? If so then it should be a bit less steep than the takeoff, but it should still be based on the height (and somewhat on the grade of the takeoff. 100' for the landing (even on a 50' jump) seems really excessive, unless you have a 25' tall jump with a 75' takeoff. On that jump the better riders would fly more than 50' though.

 

[bully_23]

thanks frudaddy I thought A 100 foot landing ramp seemed a bit long