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Distance between jumps

Jul 29, 2009
59
0
IMBA says (http://www.imba.com/resources/trail_building/build_freeride_park.html): The distance between the landing of one jump and takeoff of the next should be about 22-26 feet.

If im aiming for 4' jumps with a jump radius of 8', a gap of about 10' (is that too short?) and a landing radius of 15' (a total of about 27 feet at ground level from start of transition to bottom of landing), does the above mentioned distances seem reasonable?

I have heard that the space between jumps ought to be rounded and that flat sections dont work. I have never ridden a line where the connecting areas are rounded, but it seem to be an awful lot of digging if the distance is about 22-26 feet.

What do you think?

Thanks
Rasmus
 
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cmc

Turbo Monkey
Nov 17, 2006
2,061
6
austin
IMBA says (http://www.imba.com/resources/trail_building/build_freeride_park.html): The distance between the landing of one jump and takeoff of the next should be about 22-26 feet.

If im aiming for 4' jumps with a jump radius of 8', a gap of about 10' (is that too short?) and a landing radius of 15' (a total of about 27 feet at ground level from start of transition to bottom of landing), does the above mentioned distances seem reasonable?

I have heard that the space between jumps ought to be rounded and that flat sections dont work. I have never ridden a line where the connecting areas are rounded, but it seem to be an awful lot of digging if the distance is about 22-26 feet.

What do you think?

Thanks
Rasmus

For rhythm sections, the top of the landing to the lip of the next jump should be around double the length of the gap you just cleared. But you can tighten it up or space it out a little more depending on how you want the line to flow.
 
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D.E.T.

Chimp
Jan 21, 2004
91
3
NC
I have never seen jumps spaced that far apart, except when built on hills. Assuming you are building on flat ground, and given the dimensions you listed, I personally would not go further then two bike lengths. If you are planning on making a consistent radius between the lander and next launch, most people go less then that. You should check out some trails videos, to get an idea of what other people have had success with.
 

cmc

Turbo Monkey
Nov 17, 2006
2,061
6
austin
this is a super-beginner spot. good trails don't look like this:



just get on video.google.com and type in "bmx trails" and watch a bunch of videos... you'll start to see what it's supposed to look like.....
 

Salty4X

Monkey
Jun 17, 2006
222
0
the truth is, there is no formula as to how far jumps or pits should be spaced. It seems that there are far too many people trying to build stuff by using measurements and THIS IS WRONG. Well, I guess I was wrong, there is a formula, it's called trial and error/sweat and blood. Go build a jump, if its not right move the landing or lip.
 

Zach Dank

Turbo Monkey
Jun 28, 2005
1,300
0
Gnarcal
$hit is straight retarded. There is no set distance between lander and take off. At real trails, it should vary greatly between each set.
 

kidwoo

Celebrating No-Pants Day
Aug 25, 2003
26,904
4,580
In my pants
I'm actually building a jello mold for the most mathmatically correct dirtjumps ever built.

Fill it up with dirt, then flip it over with a bit dual rotor chopper.

The back of each lip and landing has an IMBA logo embossed.


No mistakes!!


No universal formula exists for a double without taking into account things like elevation loss and the shape/type of jump before it and the speed you have coming into it........not to mention the type of jump you want to build.

There's no such thing as absolute right or wrong.....just how well you can execute the ideas you're after. Just be willing to accept that something you built may suck and that you have to try again at a better execution.
 

TortugaTonta

Monkey
Aug 27, 2008
540
0
I see what he is sayin. Rythem, flow, curves, fluid and most importantly. . . soul. . .

 
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Pete..

Monkey
Feb 11, 2009
450
0
Santa Cruz
What you have to do is build a lip where you want it to be. Row-sham-bow with your buddies to see who has to hit it, have the loser hit it. Where ever he/she lands, mark it and build the landing there.



Back years ago I honestly thought people built like that. It made the massive booters of HellTrack and big gaps of early NWD movies seem much much gnarlier.
 

cmc

Turbo Monkey
Nov 17, 2006
2,061
6
austin
what are you trying to say bro, that dirt jumps are like waves? cause they sure as sh!t are not. nothing involved with djs is that fluid or consistent, theres too many factors such as soil quality, compaction, slope, wind speed, angle of approach, and the angle of the lips and landings,, i could have a jump going downhill with a 90 degree lip and landing with a 6 foot gap but 20 foot transition into the next jump, that does not fit the symmetry of a wave. no comparison.
i tried to write an explanation, but i'll do a drawing instead and get back to ya.
 
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allsk8sno

Turbo Monkey
Jun 6, 2002
1,158
33
Bellingham, WA
i like the wave idea, fits well with many dirt jumps personally i like to have about a bike length between the start of the lip and the bottom of the lander or more of a mellow bowl between my jumps but when it comes to dirt jumps i don't hit stuff thats too big
 

sittingduck

Turbo Monkey
Jun 22, 2007
1,962
2
Oregon
If im aiming for 4' jumps with a jump radius of 8', a gap of about 10' (is that too short?) and a landing radius of 15' (a total of about 27 feet at ground level from start of transition to bottom of landing), does the above mentioned distances seem reasonable?

I have heard that the space between jumps ought to be rounded and that flat sections dont work. I have never ridden a line where the connecting areas are rounded, but it seem to be an awful lot of digging if the distance is about 22-26 feet.
For a rhythm section, a constant transition between the landing and the next lip is ideal. For the jumps you are thinking about building, you wont need a lot of distance inbetween. Build the first two and try and get a feel for what seems right to you....
 

TheTruth

Turbo Monkey
Jun 15, 2009
3,903
1
I'm waving. Can you see me now?
speaking of which, today I realized I have out grown my jumps. It really sucks.

on topic: you build a jump based around how much speed you can get from the start and how much flow you can cary over the other jumps. Build as big as you can until they are too big to clear. Then take a little bit off. bwahaha! You can always progress into them.
 

cmc

Turbo Monkey
Nov 17, 2006
2,061
6
austin
n
Didnt mean to get hasty. All I know from my personal experience is that every set of jumps or trails is unique and I build my jumps to the tune of my specific location. I like to build a double, hit it, make any adjustments necessary, and once its DRY AND PACKED only then I can get a feel of how far away the next lip will be. Of course that depends on if its goin to hip, or if Im going to put rollers in between, or if its going downhill, or if its flat terrain or if its gonna be a step up, or a long and low or a steep do-or-die. All I wanted to say is there is no generic rule for how spaced your jumps should be. These sort of decisions come from experience in digging, and as stated before is only perfected by trial and error. Even the guys that build the dew tour courses test ride them and then adjust them accordingly, its not like those jumps go up perfectly first try and wa la, theyre done. Dirt is not a permanent building material, the best thing about it is that it can be shaped and molded easily. The reason I dont like the wave concept is because it is symmetrical. Equal distances based on a flat plane. Thats fine if your building a bunch of jumps on a perfectly flat piece of land and they are all perfectly lined up, but thats not my idea of trails, or dirt jumps.

no you're right man, generic is bad..... but get this.. imagine a regular wave pattern... like this:

say you've got like 20 of those humps/dips in a row... now erase every third hump and turn it into a pit.... the trajectory/path the rider follows when he gaps over a double becomes a mirror image of riding in the pit.... that's why i said you want the distance of top of landing to next lip to be roughly double the gap you just cleared. an old 9th street local taught me that like 15 yrs ago but i didn't realy think about the geometry until later... i'll draw it better later if that doesn't make sense...but i think youll get what i mean...
 

sittingduck

Turbo Monkey
Jun 22, 2007
1,962
2
Oregon
that's why i said you want the distance of top of landing to next lip to be roughly double the gap you just cleared. an old 9th street local taught me that like 15 yrs ago but i didn't realy think about the geometry until later...
That sounds like a pretty decent starting point...
 

cmc

Turbo Monkey
Nov 17, 2006
2,061
6
austin
i apologize for digging up this old thread . . . but I finally got around to actually drawing what I had been thinking about........>



 
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Jason B.

Chimp
Mar 28, 2011
4
0
i apologize for digging up this old thread . . . but I finally got around to actually drawing what I had been thinking about........>



Keeping digging up old threads and adding useful info all you want as your posts are helping me with my digging in the woods! Thanks!
 

Mutt

Monkey
Jun 14, 2003
284
8
Lost on Long Island
I think CMCs point in the wave illustrations is not to suggest trails are systematic, symmetric and uniform, but rather that things moving in nature tend not to move in a 'flat' way. And that pits with long flats are dumb.

Plus, just because something is sinusoidal, doesn't mean it is uniform:



On the nerdly side of this, folks tend to describe trails as sine waves because:
a) riding on tangent waves would just suck


b) because of the constant acceleration of gravity, any 'jumping' behavior is going to be sinusoidal in pattern
c) there is an informative relationship with sine waves where the steeper the angle of the wave as its amplitude becomes zero affects how long that angle will persist and change sign. The rate of angular change is less uniform with a steeper angle, where we expect trajectory-like behavior and that wonderful perception that a rider just hangs for a second at the peak of their jump on a nice steep set.


oh..... and way, waay back to the original question, what is the use case you are asking for? Planning out a whole set of jumps/trails for a site that has to work with minimal iteration, or for your own set of trails that will never stop changing from the second you first pick up the shovel?
 

stino

Monkey
Jul 14, 2002
201
0
belgium
whoa, have been off the forum and riding for almost two years, only to come back and see scientific stuff including proper discussion about it in threads about dirts. Hell yeah, RideMonkey is still THE place for me

:cheers: