Advice on Bowl / Half Pipe'ish trail section- Mtbr.com
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  1. #1
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    Advice on Bowl / Half Pipe'ish trail section

    OK, first of all, let me say thank you for the feedback on my various questions over the last few months. I really feel like the trail I am working on is coming together, and much of the feedback I have been getting here is being incorporated directly into its design and as a result, its overall fun factor. Thanks for that!

    With some of the feedback from the last post about "rough tread", it got me thinking I should rewalk the whole trail and try to look at it with a fresh set of eyes to identify where there are further opportunities to increase the fun factor as a "priority".

    As I walked, I got to a spot in the trail that I like and not like at the same time. Its one of those sharp rights on an outsloped / off camber steep slope that immediately enters into a rocky section. Days I feel techy, I love it. Days I want to rip, it feels awkward and slow. I will be keeping the line as it joins into the main trail already so why not, but wondered, what if I kept the "main line" on the hillside / contour longer, and took it over the next ridge?

    I walked it, smooth nice flowy trail across a valley then under a tree to another ridge. Walked the next ridge and found, frickin awesomeness. I knew the valley was there, but hadn't really considered extended the trail that far on a "switchback".

    The valley is very smooth "bowl" shaped, so of course, I immediately thought, "I will name thee "Bowl Movement" I walked what felt like a solid flowy line, then went home a Google Earth mapped it. (See below).

    My question is, given a "bowl" / half pipe like setup, what are some watch outs?


    • How steep of grade should I consider for a "flowy" ride?
    • How wide of turns should I put at the apex of the "lip" on each side? Standard 10' arc or does the steep sidewall allow for or necessitate a tighter turning radius?
    • Any other watchouts / feedback from people who have built this type of section?


    I plan on riding it tonight to get a feel for the "flowiness". Obviously it is in very rough shape currently, but I want to get a solid feel before I start turning dirt. I want this section to flow and just be a nice smooth back and forth with flowy g-inducing turns. I was SUPER stoked when I found this last night and think this may be one of the highlight sections of the trail, so want to do it right! Any feedback appreciated!

    Advice on Bowl / Half Pipe'ish trail section-bowl-movement.jpg

  2. #2
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    Sidewinder at KT works well for a "half-pipe" trail section...

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  3. #3
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    Quote Originally Posted by slapheadmofo View Post
    Sidewinder at KT works well for a "half-pipe" trail section...
    Just watched it. Interesting and that looks fun. I would say that the apex arc on Sidewinder is definitely "wider" than I was considering. I know steepness is hard to judge from GoPro footage as it flattens it out, but I wonder how steep the Sidewinder valley is if you took the fall line down the middle? For example if I do a fall line straight down the valley middle for Bowl Movement, it is -24%. Average "sidewall" giving my proposed line is -45%. At a 45% angle, I would probably have to cut a pretty wide berm to give the rider room to "ride it flat" like on Sidewinder. I was thinking more of a you must maintain momentum to "stick to" the side kind of approach.

    Thanks for the video. Definitely gives me some thoughts about turn radius!

  4. #4
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    Just grabbed a GPX of Sidewinder and did a slope analysis and found that while overall (Fall Line) gradient of Sidewinder (10%) is less than BM (24%) when I match the existing Sidewinder trail (8.5% ave gradient) to my proposed BM trail (8.5% ave gradient) it was a match. I know I need to take this with a grain of salt as Google Earth is not always spot on.

    I think the steeper bowl of BM and shorter overall section distance necessitates a slightly tighter turn radius and more level traverse then the approach on Sidewinder, BUT, it does make me think I will really need to think / ride the turn radius as a key consideration. I definitely prefer the idea of flowy smooth arc over an abrupt and steep line.

  5. #5
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    Quote Originally Posted by roughster View Post
    Just watched it. Interesting and that looks fun. I would say that the apex arc on Sidewinder is definitely "wider" than I was considering.
    There's a bit of a mix as far as radii go; some turns are definitely tighter while some are more gradual. Depends on what you're going for. Could turn out to be a really cool bit of trail though - good luck!
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  6. #6
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    I think you are right on with having slightly tighter turns, and more level traverses to deal with the steeper gradient of the terrain you are building in. Depending on how "feature-rich" you want the trail to be, you could build the turns as a step-up / step-down combos, where you have a steeper jump/bump combo going into the turn to bleed speed, then another jump/bump going out of the turn to gain speed as you traverse across the bowl. One of the challenging things to keep in mind when pre-riding trail alignments is how much more speed the trail will carry once it is packed in, and defined. A turn radius that feels comfortable on an unimproved surface can feel tight and awkward once the trail gets faster as it is packed in.

  7. #7
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    Quote Originally Posted by hankthespacecowboy View Post
    I think you are right on with having slightly tighter turns, and more level traverses to deal with the steeper gradient of the terrain you are building in. Depending on how "feature-rich" you want the trail to be, you could build the turns as a step-up / step-down combos, where you have a steeper jump/bump combo going into the turn to bleed speed, then another jump/bump going out of the turn to gain speed as you traverse across the bowl. One of the challenging things to keep in mind when pre-riding trail alignments is how much more speed the trail will carry once it is packed in, and defined. A turn radius that feels comfortable on an unimproved surface can feel tight and awkward once the trail gets faster as it is packed in.
    Dude you are spot on. I have it roughly in and am already noticing from riding it as I shape the turns, it keeps getting faster and faster and I have to keep expanding the turn radius. I feel like I am getting it right but imagine I might a few more "enlargement" efforts before it is finely tuned.

    Good call!

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