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  1. #1
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    Correct shape for DJ style jump

    So I decided it was time to get the gap in the middle of my yard sorted out. The landing was too narrow to start learning to move the bike around and I recently started clearing the landing almost everytime, I hope its a sign I am getting better. I dont want to build up the take off as the amount of reconstruction doesnt seem worth it, instead I want to make the take off out of wood. I think it will also be a good experience for the future if I dont have this much dirt and space available. This way I will be able to move it to find the best distance from the landing. I am still learning about shape, height and distance and I have no reference as I am solo down here. Attached photos give reference to what I have now. When the take off is built and ready I will add the last foot of height to the landing. The shape of the take off is super sweet but I was wondering if it is vertical enough? I added dirt to the lip before in an effort to give a more vertical feel and found it knocked the fork pretty hard, I am riding the Wildcard with a 36, 5" setting out back giving 67 Deg. I recently bumped up the rear PSI to get 10% sag and firmed up the fork and since then it jumps something sweet. I dont know if it would of handled the more vertical lip I had before but the take off has compacted and formed itself to what it is now and as I said it feels pefect. My only concern is I want more height and less distance, I think. I have other floater style jumps in the forest and this is my only vertical jump at the moment and I would like to learn more DJ style to prepare for the time I may visit a DJ park.
    I have tried to look at DJ jumps in magazines and in videos but never seem to get a nice angle.
    SO I was wondering if any of yooz boyz can give me some tips here. How vertical is too much or too little? Do I need to roll the lip a little to allow my front wheel to leave the lip smoothly?
    I will be using ply wood reinforced with 2x4s.

    Correct shape for DJ style jump-p8210013.jpg

    Correct shape for DJ style jump-p8210003.jpg

    Correct shape for DJ style jump-p8210006.jpg

    Correct shape for DJ style jump-p8210015.jpg

  2. #2
    ready to ride
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    looks pretty good to me

    it would suck to case that right into the plywood on the landing

    pics of landing please
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  3. #3
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    Correct shape for DJ style jump-p8210005.jpg

    Its a bit of a step up but I still clear it and land on the tranny. Thats why I am wondering if I need to make the new take off a little more vertical, more height less distance. It still has to suit the Wildcards setup though. When I jump this gap on the hardtail I really have to be carefull not boost too much or I land to flat. The hardtail is setup for winter trail riding now so the Wildcard will cover yard riding. I have my lights setup now so I will be doing a lot of night rides during winter and plan to really get this gap down. Hope to have some style by spring.

  4. #4
    Pivotal figure
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    Your angle looks pretty decent, it's gonna be tough to get more vertical without adjusting your bike's setup. A bigger gap or more tranny is probably what you're going to need. Like the ladder drop in the background How do you get to it?
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    from this and your other pics of your backyard I've got to say that you've got the coolest backyard I've ever seen!
    I like bikes.

  6. #6
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    Taller/steeper for more height but not distance.
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  7. #7
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    yessir. a regular playground.

  8. #8
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    Looks fun. All I would recommend would be cut those 4x4's so they are flush with the rest of the landing.

  9. #9
    Err
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    12' radius is what you want for nice pop without too much bucking. I believe that this is the spec that Whistler uses, the land of mathematically perfect jumps. We built our lake jump with a 12' radius, worked real nice

    Make your landing bigger (wider) too, so you have room to really move the bike around

    Might help to make a template.

    Speaking of lake jumping, why does the summer have to be over already?

  10. #10
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    12' radius sounds reasonable, but a little bit more info is needed. How many degrees or radians?...0 being flat and 90 or pi being vert. Somewhere between 60 and 80 degrees is my guess. Any thoughts?

    I could really use some numbers in my building... I just eyeball it and sh*t always comes out all weird.

  11. #11
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    Quote Originally Posted by Err
    12' radius is what you want for nice pop without too much bucking. I believe that this is the spec that Whistler uses, the land of mathematically perfect jumps. We built our lake jump with a 12' radius, worked real nice

    Make your landing bigger (wider) too, so you have room to really move the bike around

    Might help to make a template.

    Speaking of lake jumping, why does the summer have to be over already?
    If you build another one next year PM me, Id be more than happy to dig, tow a ramp, or bring drinks for who ever to hit that next year! I've got a lot of stuff in my head I wanna try that I cant without a lake jump or foam pit.

  12. #12
    moaaar shimz
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    Quote Originally Posted by i'm itchy
    12' radius sounds reasonable, but a little bit more info is needed. How many degrees or radians?...0 being flat and 90 or pi being vert. Somewhere between 60 and 80 degrees is my guess. Any thoughts?

    I could really use some numbers in my building... I just eyeball it and sh*t always comes out all weird.

    That would account for a straight (constant gradient) jump, not a kicker-type jump.

  13. #13
    moaaar shimz
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    Like this.
    Attached Thumbnails Attached Thumbnails Correct shape for DJ style jump-.jpg  


  14. #14
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    i was imagining a circle of radius = 12'. The outer surface if the circle being the surface of the lip. 90 degrees of a cirlce is a quarter pipe. My question was how many degrees (out of 360...but realistically out of 90) is suitable for a kicker. I didn't mean a triangular wedge with a "steepness" given by an angle.

  15. #15
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    haha yeah. exactly what i meant. didn't see your response...but still begs the questions of how many degrees.

  16. #16
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    tacubaya - that photo has a copy rite, I see you in the woods and you be limping for a week when I is done.

    Kenbentit - that ladder drop was one of the original features with the plan of making it a little more technical having it off camber and slow. It was something to help me learn to grow balls but I never developed a line to link it up. Not enough speed to hit the main gap and originaly I was planning to have the gap as a 4X style double, step up thing(dont know what its called). I wanted to learn to gap and manual. I have done some new things so I should look at it again and see if it lines up with anything now. Basicaly you just climb up the rocks.

    So folks I take it I can lay down my ply board, Take a section of rope/string 12' long an mark the wood as part of a circle?

    No one mentioned if I should roll the lip to smooth the take off? Is it necessary? Maybe its not needed with a 12' radius.

    Please dont look at the 4x4s or any other oddities in the landing, like I said its not finished yet and I dont plan to do it till the take off is built. I already have a step up and finishing the landing now would be interesting if I cased.

    Err - I just widened the landing for the reasons you mentioned. It was sketch before and what got me to thinking about it was when I started to try whipping and the rear started knocking out the sides. The take off is off center because I widened the landing to the left. When the take off is built I can move it to the center and set the gap. Should be done in a week or so.

  17. #17
    Now with More Wood
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    JP, always nice to get updates on your backyard. Made me remember that I need to go out on my new trail project and build a (somewhat) proper DJ double somewhere. I always struggle with lippier jumps when I don't ride them for a while (come to think of it, I always struggle with lippier jumps, period... ).

  18. #18
    Now with More Wood
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    Quote Originally Posted by Err
    ...Speaking of lake jumping, why does the summer have to be over already?
    The end of summer looked like it was about 20-30 minutes away in that picture...

  19. #19
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    Iceman, Thats why I build. Also trying new stuff that helps me learn and keeps me on my toes. I really struggled to ride stuff built by others in the UK when I started out, now I am preparing. Cant believe the progression since January, now I gotz to keep doing it. It never ends really. I still got half a trail to finish in the mountain and a new flow line in the woods next door. My wifey's camera is back from repairs monday and she knows shea has a day of shooting next week, will post when she delivers.

  20. #20
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    Quote Originally Posted by juan pablo
    tacubaya - that photo has a copy rite, I see you in the woods and you be limping for a week when I is done.

    No one mentioned if I should roll the lip to smooth the take off? Is it necessary? Maybe its not needed with a 12' radius.
    No, you want to have a distinct edge on the lip of a dirt ramp. Rolling the lip isn't a good idea because it will wear down very quickly with all the dynamic loads that will be placed on it.

    from this and your other pics of your backyard I've got to say that you've got the coolest backyard I've ever seen!
    Uh uh. My backyard park is the coolest. Though Juan's is most definitely the most picturesque and organized. His yard is a work of art.
    Jump it onto something off of something or over something.

    There's more to freeriding than dirt jumps.

  21. #21
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    Quote Originally Posted by juan pablo
    .......I still got half a trail to finish in the mountain and a new flow line in the woods next door. My wifey's camera is back from repairs monday and she knows shea has a day of shooting next week, will post when she delivers.
    Hi JP,

    Wonderful work with your back yard! Congratulations!! I look forward to seeing the pictures of your trails!!!

    Take care,

    Michael
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  22. #22
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    jump looks good to me....make it more lippy to put you in air higher or make it shorter to make it a "step up like"
    the trick is ENJOYING YOUR LIFE EACH DAY, don't waste them away wishing for better days

  23. #23
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    Okay, so I hammered a spike into the ground and pulled a 12' pices of rope with a marker on. Drew a curve to check and then laid my plywood down. Seems like a 12' radius gives a more floater style take off that I would think more suitable to full sus bikes. The base of the jump worked out to be 7' for 4' of height, sound about right? I have my landing set up to be raised to 4', maybe 5' with a bit of additional work.

    So I took a guess and shortened the rope to 7" and drew a curve again and took it over to my current jump which measures a measly 2 1/2' with a base of 3 2/3', by luck the jump matched the 7' radius curve almost perfectly.

    So I am unsure if a 12' radius is enough of a DJ style setup? With my current jump I am clearing the landing which is a slight step-up and prolly looking at an 6-8' gap but I dont feel like I am getting the height I am looking for. I havent got much room across the yard so I cant pull the take off too far back and I aint moving the landing. I also dont have much space after the lading before the small berm which stops me heading down the back and into the fence.

    Any ideas?

  24. #24
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    I haven't read the whole thread but depending on the size of the jump you can go up to 70 to 80. For a jump that size, I would probably go more like 60 to 65.

  25. #25
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    i have this long standing theory on dirt jumps and gaps; when you see video of people going through a rhythm section some riders go higher than others, but they all land on the landing ramp,if you "overclear the landing" you're skrewed for speed on the next jump,you want to pull back/up on the handlebars and turn your extra speed into height not distance. So i think you want to steepen your take off jump,and/or try for altitude. my experience on dirt jumps is minimal ,i clear everything at diablo that counts for something but it's not really a rhythm section,they're big enough to pedal to regain speed if you over jump.

  26. #26
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    Yup, thats what I am trying to do now - pull up on the bars and almost bunny hop to get height. I get the feeling my jump is not really that big and though I have tried to make sure my tranny is long enough, really my front wheel will be leaving the lip when my back is still at the base of the jump. Maybe I am expecting too much from such a small jump with a longer travel bike. When I jump my hardtail I really need to be carefull not to boost too much, way more responsive.

    I will keep playing with it but since its not gonna be dirt I cant scult and shape like I have always done.

  27. #27
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    You should be able to boost the height even if your bike doesn't actually fit on the ramp. We used to try to boost height off of "curb cuts"(the jumps on the sides of driveways) on hardtails and bmx bikes, even a bmx bike doesn't fit on those jumps.

  28. #28
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    mmm, I took some vid this weekend just to see what footage I could get and used it too see whats happening at the same time. It seems to me my front wheel is rebounding straight over the lip. Dont know if my technical is still crap or if thats just a result of 160mm of travel. I am thinking of getting the hardtail onto the jump again this week. With a domain up front I can get it nice and low and stiff at the same time. The reason I want to run my Wildcard is just for more all round use. I have some nice drop offs, little rough sections and good trails in the forset over the hedge, it just feels nice and cumfy. I can hit it all on the hardtail I just feel it at the end of a good weekend riding.

  29. #29
    Locs on Spokez
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    The best way to learn to make a nice lip is by practice... Just keep sculptin and you'll end up with art....

    Check out mah album ;] http://iggz.pinkbike.com/album/Locs-on-Spokez/
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  30. #30
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    I'm not the best dirt jumper, still learning, but I know you can change your trajectory by where on the jump you compress the bike hardest- when you pre-load and "pop" off a jump, try focusing your "pop" or "push" sooner vs. later on the curve, and see how that affects your height vs. distance.

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