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  1. #1
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    need help with wooden berms setup

    ok guys our local trail is extremely flat if i had to guess no more that 10ft of elevation change inside of 4 miles. we have 4 miles worth of trail packed into just a hand full of land next to the river. its a really slow trail with nothing but spinning single track.

    on the last section there is a mound of dirt that has been turned into a bridge to gain some good speed but it leads into an of camber 180* turn. i am going to build a nice very sturdy wooden berm in this turn so that the speed can be kept up. the materials will be rough cut 2x4 (so 4.5x3") A frames, RC 1x4s to join the a frames together and RC 1x4 slats. if you are coming off the mound at say 20 mph into this berm what kind of angle would be best for the berm? im thinking steeper in the middle and taper down on the ends. we cant really do dirt as its very fine powder type dirt, and sand. not to mention the trail goes under water for a couple of months just about every year.

    i really appreciate any and all help with this! if a pic is needed i will try to get some tonight during our ride.

  2. #2
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    Can you use concrete to make kind of a bowl section?

  3. #3
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    I recommend using sills, stringers, and decking no smaller tan a nominal 2X4. You might be able to get away with 1X4 cross bracing; I use nothing smaller than 2X4.

    Here's how I've built a few: I usually bury to ground level a 4X4 sill on which the stringers sit. Fan out your sills evenly spaced around the arc of the turn to determine where they'll sit then bury them. Measure the distance between the sills and allow for a little overlap. You can also set them center-to-center. The latter makes the decking smoother. Lay out the first sets of stringers across the sills, making sure none of them touch the ground. Dig down if they do.

    I use 4X4s for the posts that the back stringers sit on and toe nail them into the sills. The stringers will be fastened to these posts. Don't nail the posts yet.This gives you the height you want for the back of the berm. I set a piece of decking, usually 2X6, on the front stringer and the post in the back and use a digital level (smart tool) to determine the angle I want the berm. Do this for each post to ensure that the angle remains the same, i.e. if you want it to be the same. Cut the post to the height you want and at an angle that allows the decking to sit above the post.

    Next, measure the distance along the sill between the front stringer and the back post. Cut a 2X4 and nail it between the 4X4 and the front stringer & then nail the front stringer into this board. Set the back stringer to the height you want and nail it into the post. If you want a little more structure in the back, cut a piece of 2X4, nail it to the post under the stringer. Do this for the remainder of the structure.

    Add decking. Add dirt to the entrance and exit as needed.

    Edit: I used 2X4 decking for a tighter radius on these below.





    D

  4. #4
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    Quote Originally Posted by dburatti View Post
    that looks like an awesome section...how fast are you going through that?
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  5. #5
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    cant haul that much concrete into the trail.

    thank you dburatti, those pics clear up a lot! if you have pics of other wooden features please share them. like i said, the trail is extremely flat and after 4 years its really just not fun to me any more. im wanting to do some big wooden rollers or anything else like that.

    again thanks for the pics and explanation!

  6. #6
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    Here are some pics from Silver Star... We were going to do something along these lines but it never happened. Plan was to use peeled logs for the structure and rough cut lumber for the decking,
    Attached Thumbnails Attached Thumbnails need help with wooden berms setup-dscn3632.jpg  

    need help with wooden berms setup-dscn3636.jpg  

    need help with wooden berms setup-dscn3638.jpg  

    need help with wooden berms setup-dscn3657.jpg  

    need help with wooden berms setup-dscn3658.jpg  


  7. #7
    Builder of Trails
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    Quote Originally Posted by henry9419 View Post
    that looks like an awesome section...how fast are you going through that?
    10 - 15 MPH.

    Quote Originally Posted by superspec View Post
    thank you dburatti, those pics clear up a lot! if you have pics of other wooden features please share them. like i said, the trail is extremely flat and after 4 years its really just not fun to me any more. im wanting to do some big wooden rollers or anything else like that.

    again thanks for the pics and explanation!
    I'll try to post pics of some other stuff later. I built a set of rollers that didn't quite come out how I wanted them to. I placed a sill at each...articulation, each spot I wanted there to be a rise or fall in the steepness of the roller, and that used a LOT of 4X4s.

    Outside of matching the feature you're building with the trail speed, I think the toughest part is framing the structure, any structure.

    Here's a shot of the start of a boardwalk frame and a .jpg of a basic ladder bridge/boardwalk structure I drew.

    I'll try to post some pictures when I get more time.

    D
    Attached Thumbnails Attached Thumbnails need help with wooden berms setup-ladder-bridge.jpg  

    Attached Images Attached Images  

  8. #8
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    how do you get your materials to the point that you are building on? our trail is fairly tight so we cant really build anything at home and its surrounded by water on 2 sides year round and 3 at some points in the year. are you using a chain saw to cut the lengths or a hand saw?
    Last edited by superspec; 09-22-2011 at 06:44 AM.

  9. #9
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    here is a vid of the first section of the trail. please excuse the redneck accent and poor camera quality.

    at the 7;30 mark is a place that i want to do a good roller into a big 180* berm at like 7:33 or so.

    if you see a good place in the trail to put something please say something and what time mark it is at.

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    MikeShore71201's Channel - YouTube

  10. #10
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    Quote Originally Posted by superspec View Post
    how do you get your materials to the point that you are building on? our trail is fairly tight so we cant really build anything at home and its surrounded by water on 2 sides year round and 3 at some points in the year. are you using a chain saw to cut the lengths or a hand saw?
    I load my truck & drive as close as I can to the spot. Then, I hand carry the wood in.

    I use a chain saw to cut it to length on location. I am not a fan of building a feature off-site and carrying it to location. I prefer to build the feature to fit into the land.

    D

  11. #11
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    where i want to build stuff is no less than 100 yrds walk into the trail. typically there is little to no help gettings materials back there so many many trips are needed. i wish there was a way to drive close it would make life so much easier haha

  12. #12
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    I've used a makeshift travois from a tarp to move more lumber than I can carry.

    D

  13. #13
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    that would be great but the trail is so tight and winding that pulling a long length is almost impossible without it hanging up.

  14. #14
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    I posted stuff over in the DJ forum about this.... but might as well re-post here...

    Wood Berm for Backyard Pump Track

    wood berm at Ray's MTB Park




    Here's a wood berm at the I-95 Colonnade bike park in Seattle. I took this photo on a recent trip to the Northwest.


    Here's another one under contruction at Duthie Hill outside Seattle:



    flat bank style with dirt transition going up to it. @ Whistler. flat banks are not necessarily thought of as "berms" but if you think about it they can function the same way, you hit it from one direction, turn and leave in another direction....



    pic i took of one of the awesome 3-tier wood berms at Whistler.



    Joyride150 wood pump track





    Winter Park - Trestle BIke Park:

  15. #15
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    beautiful! keep them coming.

    something that crossed my mind today: if i do a set of 3 rollers no more than 2-3 feet tall how much distance should i have between them?

  16. #16
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    Quote Originally Posted by superspec View Post
    beautiful! keep them coming.

    something that crossed my mind today: if i do a set of 3 rollers no more than 2-3 feet tall how much distance should i have between them?
    cmc4130 is very good with roller height/spacing ratios. He has helped me out in the past. There is a thread on it in the dirt jump section where he has a buttload of diagrams showing the ins and outs of roller height to roller spacing ratios.
    Here goes a link to it.
    DJ , Pump Track plans

    Rollers would be a great way to add a new element to your trail what with so little elevation change - you can gain some nice speed with rollers. It's also a great workout.

    You'd be surprised how much speed you can gain with some 15" tall rollers. In fact if you look at the indoor pump track he linked in the post above you, you'll see where the rollers are no where near three feet tall.

    Are you in NC?

    Good luck!
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  17. #17
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    NE louisiana

  18. #18
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    Ah, I saw Forsyth on the video and we have a Forsyth county here in NC (and we also talk like rednecks ).

    I can't remember if he talks about double digging in that thread or not, but it's a pretty efficient way to build your rollers with half the required work.

    In a nutshell, mark out your roller peaks and roller troughs. Dig down at the troughs and throw it where the peak should be, shape, continue.

    If you want 15" rollers you only have to dig 7.5" down (and pile dirt 7.5").

    If I remember correctly, I used 15" rollers and a 12ft spacing peak to peak as my main spacing.
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  19. #19
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    no digging will take place. this is next to our river so the trail goes under 3 out of 4 years for weeks to months at a time. im going to build everything out of heavy wood and anchor it in the ground with rebar and post driven in so that hopefully the current wont drag it away or tear it to pieces.

  20. #20
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    Quote Originally Posted by Jason B View Post
    cmc4130 is very good with roller height/spacing ratios. He has helped me out in the past. There is a thread on it in the dirt jump section where he has a buttload of diagrams showing the ins and outs of roller height to roller spacing ratios.
    Here goes a link to it.
    DJ , Pump Track plans

    Rollers would be a great way to add a new element to your trail what with so little elevation change - you can gain some nice speed with rollers. It's also a great workout.

    You'd be surprised how much speed you can gain with some 15" tall rollers. In fact if you look at the indoor pump track he linked in the post above you, you'll see where the rollers are no where near three feet tall.

    Are you in NC?

    Good luck!
    yeah, thanks. i guess one key to remember is the faster you want to go, the mellower you can make the curves. i drew these ones at 2 feet tall and 15' spacing.... but mellowing out the arcs they could definitely be 2 feet tall and 17 or 19 foot spacing as well.


  21. #21
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    holy **** that is a lot of planning!

  22. #22
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    CMC can you show me a pic or a drawing of how you would lay out the 2x4 runners for set of rollers? i was thinking cut 1 foot 2x4 sections with like a 5*angle on each end and butting them together with a short 6inch piece screwed to each section to brace them. if i had a working scanner i would draw it up so you could see more clearly what i am thinking.

  23. #23
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    Very helpful. Has anyone built stuff like this incorporating Eucalyptus? If so, any tips? I know it's not an ideal building material for many reasons, but we have literally tons of it that's been felled while clearing lines in our skills area project and it'd be great to put it to use.

  24. #24
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    Quote Originally Posted by superspec View Post
    CMC can you show me a pic or a drawing of how you would lay out the 2x4 runners for set of rollers? i was thinking cut 1 foot 2x4 sections with like a 5*angle on each end and butting them together with a short 6inch piece screwed to each section to brace them. if i had a working scanner i would draw it up so you could see more clearly what i am thinking.
    i took these pics at Winter Park:



  25. #25
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    well hell i didnt even think about using some 2x12 and cutting my shape. why must i always want to over work myself haha.

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