The Ultimate How To Build Dirt Jumps

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The Ultimate How To Build Dirt Jumps
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O+ FL
Posted: Oct 13, 2007 at 8:19 Quote
*THIS WAS ALL WRITTEN BY URBAN-RIDER_TOM NOT BY ME*

ok let me begin..
good dirt jumps are only made if you put the time and effort into making them, this takes commitment and motavation...if you dont have this then dont bother reading the rest.
here is something too wet your appatite and build some motavation....

these are belton trails near birmingham in the uk. with time and hard work, trails like this can be achived!



a sure fire way of knowing if yor dirt jumps are going to be good can be judged on youre location

location.
there are two main places to build dirt jumps. in a field or in a forest. they both have there pros and cons, like a field s good because there are no trees in the way and easy to get too. but they dry out and crumble or th wind stops you from riding and they get found by the wrong people. digging in the woods is good because jumps are hard to find and are protected form wind, sun and diggers ect but is bad because they have to turn and sometimes are always wet.
you want the jumps to be on a slight downhill and the run up to be steep (although the jumps can be on flat but you need to be very good at pumping)
the most important thing to concider in the location is the run up. a good run up is down hill and straght and about 80 foot long. another thing to concider are how many jumps you want to build. a medium sized 6 pack should take up about 80 feet of space. dont forget the run out!!! you can build a berm at the end. try to get planning permission from the counsil and if its private land written permission is a must. but if you are going to do the stupid thing...DONT cut down trees! and dont drop litter and try to hide them.

Equipment
get some decent trail building equipment. this will last you and will pay off,
you will need...

a spade (prefebly long handled)
a small spade * (for fine work)
a shovel for shifting
a wheel barrow
a rake
a pick*
a watrering can*
a broom*

* not essential

getting started
once you've found you place and got permission!!! try and get motavation. search google for images this will give you a better idea of what you want in the end. round up a group of mates to help. work will get done twice as fast.
check the mud in the area. if it is sand then your jumps aint going to last long...sand crumbles when its dry and sould be keept wet. what you are looking for is clay. goes rock hard and super smooth. although it is hard to dig....dont put stones in the jumps and DONT USE LOGS!!!! these ruin the shape of any jump. all good jumps are 100% dirt.
clear out the run up and the area where you are digging of weeds and overgrowth, (not trees) do this by choping the bottom of the weed then swiping it with a spade. this will make digging alot easyer. then get sticks and mark out where you want to put the jumps this will help getting a better idea of what you want to get.

The dirty work!
the first steep is to pile the mud up...
the best time to dig is in the rain. this helps the jumps to pile up and will make life alot easyer. dont go and dig a random hole! you get the mud from the bowls in between the jumps. the best jumps start with a set up jump, this has a small take off and no bowl infront of it, they have a fast kick. the best way to pile up mud is to do it in levels, these are the base (a foot of the ground) the middle and the lip. at each stage stamp down the mud on top, and stamp down the sides. the shape you want to get is a square base and a sloping sides, a sloping top and a rectanguler top. this will help them get stong and give a level base to build onto. the best way to dig out the ground is with blocks of mud and slap them on the pile. these go hard faster.
the landings are steep and have a bowl that goes deeper than ground leval. these help to get you into the flow of the jumps and help with speed. the bowl should have a constant curve. no flat bits and should be as smooth as it possably can. bumps take away momentum. the deepest part of the bowl shoulod be in the middle. keep in mind drainage....

shaping
this is where you need patiants(sp?) this is an art you know! firstly stamp down the jump with your feet, this helps to get a basic shape and compresses the dirt, it is better to shape when the dirt is really wet. remember! the shape your trying to get is a triangle with a flat top. the more the sides slope, the stronger the jump will be. To shape the most important part, the transition, first stamp down the mud then fill a wheelbarrow with mud and roll up and down the tranny (and only the tranny!), this helps to give it a perfect constant curve and it also packs in the mud more. after that you will notice the tranny will have small bumps so to finish it off and properly compress it, get a flat sided spade and hit it down, if mud sticks to the spade then it isnt wet enough underneath (leave untill it rains) rember the shape you wanty is a constant curve and a steep lip (but no too steep for obvious reasons) after youve done the tranny hit the sides with the spade untill it is hard. for the landing do the same but the landing should be the same steepness but not as much of a curve in the transiton.



Drainage
this is possably the most imprortant part of your trails. good drainage will alow you to ride when its been wet. dig drainge at the side of the bowls, this can be judged when it rains and you know where puddles form and you can see the direction where the water flows. dig a small hole about a foot deep half a foot wide and a foot long, this should be enough depending on the earth you are useing.


Tabletops!
i have added this because a user asked. this is where a wheelbarrow and alot of friends comes in handy!

these are good because you can add / takeaway as much of the lip / landing as you want without moving the jump itself.

a good size to start with is a bowl infront of the first (for the mud) of arould 2 foot deep and 4 foot wide, and 6-7 foot long. the table should only come about two foot out of the ground. (so in theory, the jump is 4 foot heigh) the length should be about 5 foot. a steep landing is good on tables too.
use these measurements for the next one but add about a foot accrordingly to the gradiant of the ground you are working on.

start by filling a wheelbarrow with mud and making a massive pile where you want the jump to be, it doesnt matter if the pile isnt even.
every now and again, rake the pile even and stamp it down. then pile more on.
when the height you want is achived, start pileing the mud infront and behind for the landing and take off. stamp this down and keep adding! (the more you add, the longer the jump)
do exactly what i said in the shaping section to create the tranny and landing. these are very easy too build but take a long time. the more you add the better, also, using your feet for the packing down is better because it applys more pressure.

Maintanance
too wet to ride eh??! well dont be miserable. grap a waterproof coat and do some patching up on your trails. these tips will prolong the life of your jumps.

if it is wet..
*start by picking up any litter (for obviouas reasons).
*rake up sticks and leaves from the run up, bowls and run out.
*make sure the drainage is effective.
*fix the lips of your jumps by slapping on some uber wet mud and shaping it.
*fill in any cracks

if it is dry...

*sweep up the dust
*wet the jumps
*clean up the litter
*try to patch up the broken lips


Toms top trail tips!
1. reguarly water the jumps, this will stiop them from crubling apart and make them stronger
2. do not drop litter
3. dont dig random holes for dirt, use bowls in between jumps
4. round up a group of mates to help you
5. reguarly maintain the jumps i.e fill in cracks and fix cased lips
6.dont chop down trees
7.get a strong person to do the pushing the wheelbarrow shaping!!!
8. take your time, trails dont get built over night
9. dig in the rain, this defiantly pays of when it comes to shaping
10. try and get permission, if not the dig well away from civalisation, i.e over streams in the woods, this will stop diggers from bveing able to buldoze them!!!
11. dig over winter when you cant ride, the jumps dry out slower making them harder and dont crack
12. file the ends of your spades sharp. this helps with cutting and chopping through roots
13. letting grass / weeds grow on your jumps will hold them together better.
14. sweep up the dust, this will make pedaling easyer and grip better.
15. carpit holds lips togeter and increses grip

JaRgOn BuStEr!
what the hell does that mean? i hear you say. look no further!

double. two piles of mud formed into a dirtjump with a varied size gap inbetween.

table a dirtjump without a gap, can be rolled over, good for begginers.

Rolling double a double with very slack backs to them, they can be rolled over. good for begginers wanting to learn doubles.

tranny or transition the curved bit at the front of the take off / landing. these should have a constent curve.

gradiant the steepnes at the top of the lip. 45 deggres will give the most distance and height. steeper the better (more air time.....whoooo!)

bowl the area inbetween the landing and take off. these should have drainage and a constent curve, they should be around 2 foot deep depending on the height of the next take off and have the deepest bit in the middle. get your mud for the next jump from here.



Other pointers from other users, and my comments.
sorry if i get any of your names wrong...thanks

1. "another tip i have for packing jumps is to use a 3 or 4 foot 2x4 and just go to town on the jump...it will be packed and hard as hell when you are done...so fast so easy!!!," boi

a very good tip, but make sure you get it all smooth with a spade again after! thanks for that

2. "I just have one thing to add, when you are building them and are in the final stages of the jump and tranny use your foot to pack it then kinda rake it so there is a soft layer then use your feet to pack it again. this is better than the shovel because more pounds per square inch is being applied. do that sequence about three or four times or untill you feel that your jump is packed enough.and for the final touch leave it just with the rake lines..it looks nice," bigbobby1590

i tried this the other day, good tip, but i suggest raking it, then stamping it then rake, then stamp ect. finishing it off with a spade for ultra smoothness!. but make sure you stamp it down good or it sticks to the spade when wet.

3.ive got a tip to form solid lips me and my friend use this take 2 peices of scrap ply wood say 2' or 3' long by 2' put one on the top and one person stand on it and the other you jump on the back 2 pack the lip ds_fr4life

This is good because it compacts the mud from 2 places at once, and stops the mud from getting spread out, allowing for less time digging and more time riding!

4. my friend used cement one time. he didn't do it right but this other guy did it and it was wicked. just get some normal dirt or clayish dirt and put it in a wheel burrow with some water and just pour in some powder cement and follow the instructions. _*StITcHeS*_

this is an awsome tip, a friend of a friend did it once and the jumps went solid, and i mean solid!. just make sure the layer is thick so it doesnt crack. also try applying it with artexing utencils, ultra smooth!

5. "Even better is to build table landings. Build the dj normally, but fill a little bit before the normal landing in with dirt. It saves lots of work but still has a table part that leads to the landing. Basically it's a table top with some of the first part of the table part is took out." muphdog

This is a great idea for when you are progresing, build a table first, then take a little away out the middle when you get more confident...pure genius

6. "when building dranage, make the place where you ride slightly slanted like a road, so the water will run down to the sides and then dig a dranage hole where it pools. or you can dig a deep hole, then fill it with rocks, then put soil on top so the water drains through the soil and pools beneth the rocks, this aint as good because the soil will soon wear away from the surface. hope this helps, mark." mark_24

i like the rocks idea although it would be a pain in the arse to get right, and the slanted sides is the methord i use and it works a treat.

7. a hint for working with clay ... dont try to pack it down ! ... the clay is heavy enough that if you leave it to set for a few days it will be semi packed down .. after it has dried out and set a bit, then you can pack it wiht your shovel or shoe...sure its a hassle not being able to hit the jump the day you build it .. but in the long run its WAY worth it ... clay packs down like rock over time. smashnuk

defiantly. we never packed ours down over winter and now they are solid and only need a small amount of shaping to make them smooth.


8. another tip for working on your jumps ... if you see those jumps in the pictures .. the thing that the trail builders never do is just randomly pile dirt. you have to know how to place things in order to get that perfect shape. when we are building jumps in our forest the dirt there is moist clay so it makes for awsome jumps .. IF you know how to work with it. when we want to make a lip tall and uber steep you dont just make a random tall pile so you can pack down the face and jump it. sure it will work but it makes for a sh!t jump.. you have to make sure that the back and sides of the jump are well done before you can even think about the face. if you want to make a jump tall begin with a medium sized pile, then add dirt to the back and sides of the jump by smacking it in place, not just dropping it on. when you smack it in place it semi packs it and helps give your jump the perfect shape in half the time. and its obvious how to go from there .. if you want the lip wider you slap dirt on the sides, and if you want it taller you slap dirt on the back and then slap it on the top. when i build i worry about the face of the jump LAST. this is because when you want to make a strong long lasting jump the sides and back are what is supporting the jump, so those MUST be well done in order to give the jump its longevity. onse youve shaped and WELL packed down the sides and back, start shaping the lip. also by packing down the sides and back, the jump will not simply crumble as you get closer to the top of the lip when packing. the order i do things is i first get about 3/4 of the dirt i need in a pile, then i slap dirt on the sides/back/top according to how i want the lip to be, then once i have it at its preffered height/width i pack down the bacl of the jump, then the sides then the top. after i pack the top i redo the sides and back a small bit. now i do the face. once everything has been shaped the way you want pack everything over again ... like ALOT, and your jump should be ready to ride in all its uberness in no time at all. smashnuk

couldent have said it better myself





Thanks all for your comments, i do apriciate it!


i hope this helps you out!

Tom


p.s. all this is my own original content. i made this because i want to help people out and give something back too the mountain biking community. feel free to copy it onto other forums/ websites ect, but please say where you got it from and who off.
pictures soon! (i promise) all these ideas are my own and my friends (unless otherwise stated) and have been tested in real life with our hard work at my trails. your tips are also greatly appriciated so keep em' comin'!.

Posted: Oct 21, 2007 at 15:52 Quote
glad to see this from the old forums. sticky this up

Posted: Oct 21, 2007 at 15:55 Quote
arent there supposed to be images?

O+ FL
Posted: Oct 21, 2007 at 16:33 Quote
schmity wrote:
arent there supposed to be images?

yeh ther was but they wern workin and i couldnt figur out ther links

Posted: Feb 19, 2008 at 18:53 Quote
im stoked on building this season.. these are just awesome pointers

Posted: Feb 19, 2008 at 18:58 Quote
very very good tips, just one thing, 11. dig over winter when you cant ride, ground is frozen! at least here in canada

Posted: Apr 8, 2008 at 12:40 Quote
this is a good thread

Posted: Apr 8, 2008 at 18:15 Quote
sticky

good pointers

O+
Posted: Apr 8, 2008 at 18:46 Quote
This is already posted in the tutorials section

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