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  1. #1
    The Voice of Reason
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    Building Skinnies

    I want to build some skinnies after riding a couple for the first time this weekend. I hit one natural one, a fallen tree, and several man made. The fallen tree might be kinda hard to come by but building one out of lumber is doable. I'm not sure if I have permission from the land manager yet so I may be jumping the gun but the ones I rode were built by a city parks and recreation department so I may be able to convince them. I'm thinking fairly easy, maybe 18" off the ground, and 6"-12" wide. Should I concrete the support posts? is it better to have a solid piece of wood for the skinny or make it like a narrow boardwalk? I might have access to a pile of old pressure treated and creosote timbers and where I'm building them would be out in BFE so power tools would be out of the question (except for a chainsaw).
    I'm never gonna be a Rock Star

  2. #2
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    Best way out of the material you describe is to post hole dig about a foot or so. You don't have to use concrete if you have crushed rock you could harvest. Put the support in and fill hole w/rock. cut a V cut to the top of the support. Place a split log or a cut log. i would suggest using a 5 inch round and you can shave the top of the log to however skinny you want the tread. Then cut little crossways notches for traction. Secure using timberlok screws or galvanized spikes/nails. Simple.

    Using 4 to 5 inch rounds should be strong enough with many types of wood to span 8 feet. You'll have to figure all that out by making a mock up with the material you will be using. If it supports you bouncing on it without cracking or bowing too much you're gold.
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  3. #3
    The Voice of Reason
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    we don't have any skinnies on our trails so this would be a new experience for most of us. do you think 4"-5" might be too skinny? it does seem easy to build but you never can tell how complex something like this could be until you start building. thanks for the info.
    I'm never gonna be a Rock Star

  4. #4
    mtbr member
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    Quote Originally Posted by Megashnauzer
    we don't have any skinnies on our trails so this would be a new experience for most of us. do you think 4"-5" might be too skinny? it does seem easy to build but you never can tell how complex something like this could be until you start building. thanks for the info.
    I guess it depends on the length, and how high they are off the ground. A smooth, straight run in to the skinny will make it easier too. Maybe you can build a variety of them, some 12", some 8" and some 5". A few different lengths too. That way riders can work their way up to the more difficult ones.

  5. #5
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    There is no science to skinnies. Pretty much build what you like, but here are my opinions.

    I would consider 5" an intermediate skinny, unless it is over 2' off the ground. Anything 6" or less should be a beam. Wider than that use a ladder.

    We used to use 4x6's for skinnies, they worked very well. 6" for a wide skinny, or for more difficulty turn it on it's side for 4" which is a good difficult skinny. We used to run these about 2 to 3 feet off the ground, for a nice and difficult skinny section with the added height keeping the fear factor up there. I would say 4" is not too skinny. Of course you can get skinnier but I would keep it low to the ground. I would not hesitate to build a 2" skinny that is less than 1 foot from the ground.

    Support posts can be concrete footings, rock footings, buried in dirt, or build on a wood "foot" platform. It really depends on your situation and land managers.

    Changing elevation can be fun and challenging but too much will ruin the flow. I like putting in hard corners with a inside line for the rear tire. This is fun and can screw with the mind.

    OK, after saying all that, I have switched to building only natural skinnies and for our park we will not be building anything over 2' high, or goal is to make them difficult not dangerous. But if you decide to go for altitude, 12" at 8 foot high is like 4" at 1 foot high

    Start saving up some cash for rear disk rotors and derailuers you'll go through a lot. And do not chainsaw a creosote log, it will throw that crap all over you and burn.

    Good Luck and post pics!

  6. #6
    backwoods and backwards
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    I just put a practice skinny behind the house built from a couple of 2x 4's T-braced together. I can flip it over to ride it 3 1/2" or 1 1/2" wide, 12' long, 8" off the ground. Lot's of fun. Bikerag.com is loaded with skinny talk, worth a look.
    Moonbeam's compost-powered hybrid generates a respectable 32 fruit flies per rotting banana peel.

  7. #7
    I need skills
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    worth a look

    http://www.whistler.ca/images/storie...st_edition.pdf
    page 8 & 9 offer some width to height ratios for differ difficulty levels..

    the info is good, but if you are working with naturally fallen trees sometimes the width/height ratios may not be ideal, as the tree is where it is, but a person of reasonable intelligence should be able to recognize the hazard.

    Also, if your skinnies end up more difficult, offer a clear route around or bypass. Some builders add chokes or features prior to the skinny to slow people down, the thought being the rider will have appropriate time to judge the feature and see the bypass route.

  8. #8
    I'm on fire.
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    We usually use log supports.
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  9. #9
    The Voice of Reason
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    i'm all about natural skinnies. we got nailed by hurricane ivan several years ago. we've still got dead pine trees falling over when it gets windy. the problem is, they are pretty rotten when they fall and they rot pretty quick when they are laying on the ground. there isn't much hardwood falling over and i don't want to cut any down. the land manager has a bunch of old timbers from bridges they've rebuilt so i'll probably go that route (if they let me). 4x6's should be easy to come by. i hope i get some help dragging them through the woods.
    I'm never gonna be a Rock Star

  10. #10
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    Not the prettiest, but it got the job done.


  11. #11
    Builder of Trails
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    Someone already addresses technical difficulty and risk, and I want to add to that.

    You can have nine different combinations of skill & risk (with examples.) None of these is a specification. They are only examples!

    1. Low risk & low skill - 1" high & 3' wide
    2. Low risk & medium skill - 1" high & 16" wide
    3. Low risk & high skill - 1" high & 2" wide
    4. Medium risk & low skill - 18" high & 3' wide
    5. Medium risk & medium skill - 18" high & 16" wide
    6. Medium risk & high skill - 18" high & 2" wide
    7. High risk & high skill - 4' high & 3' wide
    8. High risk & medium skill - 4' high & 16" wide
    9. High risk & high skill - 4' high & 2"wide


    Levels can be increased by adding rises and falls in the structure, as well as varying the height and width, of course. Has anyone ridden the skills structures at Bootleg Canyon, NV? Good examples there. I have pictures and may post later.

    D

  12. #12
    Papa T
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    Our trail in NE FL we use pine trees that are impregnated with turpentine, basically this type of wood is called lighter knot and makes for great kindling. This type of wood is pretty darn near impervious to rot. We too only use the fallen ones and never cut down trees to build anything. I don't have any pictures, but all of our skinnies are at ground level, usually the tread is 8-12" off of the ground.
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  13. #13
    The Voice of Reason
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    i know lighter knot well. after said trees fall, i usually take an ax and cut them off the trail. it works the upper body.
    I'm never gonna be a Rock Star

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