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  1. #1
    That Unicycle Guy
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    Stud pattern and self steer?

    What I am wondering is if the location and stud pattern will affect how much a front tire will "self steer" eg: turning itself uphill, trying to climb out of ruts, etc.

    Background behind the question:

    It has been a strange winter so far and everything has gotten quite icy so I have been using my studded tire on my fat winter unicycle. I have been mostly been riding snowmobile trails and bush roads.

    My tire handles itself nicely on the trails, on packed snow and glair ice, but it extremely hard to keep tracking strait when riding in ruts left by a truck hauling wood on the trails.

    I have studs in a staggered pattern across the majority of the treaded area of the tire and I am wondering if that is most of my problem. I have always done this with smaller tires and never had any issues but looking at other studded tires on the forums most people seem to do just a strait line of studs instead of a staggered pattern.



    If anyone has experience with various stud patterns do you think I would have less problem with the self steer if I removed all the studs and re-installed them in two strait rows?

  2. #2
    mtbr member
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    I like straight rows, but I'm kind of a "symmetrical" guy. And, for most purpose's, I keep them away from the middle section of the tire. But that's just to keep rolling resistance down. They still grip the sides of ruts and try to climb out... but by the same token they hold well on on off camber "side hill" ice. Kind of a trade off. What tire is that?

  3. #3
    Ride da mOOn Moderator
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    Good job!

    I always stud front tires on my Motos/Quads/MTBs...

    ... in a "V" pattern with the point of the "V" facing forward.

    I don't know if studding has anything to do with , but my experience with riding in mushy or mash potato snow always allows the front tire to make it's own path, grabbing the sides of the snow and climbing up thus causing steering problems!

  4. #4
    That Unicycle Guy
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    The tire is made from two cheep Kenda tires I sewed together a couple years ago.

    It became my dedicated wide studded tire last year when I gave away the studded Duro that I never really liked anyway.

    On a 80mm GFS rim it measures out to 90mm (my Larry on the same rim is 95mm)


    The reason I think that stud pattern might be important is the idea the the outside of the tire has a smaller diameter than the centre and if you have grip both on the outside and the centre it will make the wheel want to turn to the side.

    I never thought of it much before as I can usually just deal with it but I had some of the worst self steer problems I have ever encountered in those icy ruts.

    I guess a handlebar and another wheel would have made things easier

  5. #5
    mtbr member
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    Oh ya, forgot you're on one wheel... little different physics goin' on there...

  6. #6
    That Unicycle Guy
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    not that much different. just think of the unicycle as the front wheel of a bike with no steering dampener and some silly short handlebars reducing my ability to hold the wheel in a strait line.


    As small as the fat-biking-in-snow community is you can imagine how much smaller the fat-unicycling-in-snow community is, which is why I come to you guys for advice.

  7. #7
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    I doubt it's the stud pattern,although I've always done an even pattern myself (on regular 26'rs). I would suspect it's the rut itself pushing you around. If you can lower the tire pressure any more, it might keep you from bouncing off the rut's imperfections or "walls" so much. Otherwise, I might "self-steer" onto the better trails.

  8. #8
    gran jefe
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    i blame the rut, not the tire.

  9. #9
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    Unfortunately, I have to disagree with mtbxplorer. The "stud pattern" is, effectively, the "tread pattern" for very slick surfaces (ie ice). It doesn't really have much affect on dry ground (otherwise everyone would be using studs year-round). That being established, my (and many others') experience with fatbikes (I realize you're on a uni) is that the flatter tire profile (ie the cross-section), not the "tread pattern," will cause more self-steer, as will lower tire pressures.

    Essentially, the more tread you have on the ground, the more that tread is fighting itself. So when you load only one side of the tire (ie turning or riding slightly up the side of a rut) the contact patch goes from a nice eliptical shape, centered on the tire, to a more trapizoidal shape that's off-center of the tire. This causes the tire to roll as if it's a cone laying on it's side (ie steering itself one side). This is known to happen regardless of "tread pattern."

    sorry if that's a bit confusing, but I wanted to try to cover all my bases.

    EDIT: now that I've thought about this for a little while longer and actually built some virtual models to test, I'm beginning to question the widely held opinion that the Endomorph self-steers worse than a rounder profiled tire like the Larry AT LOW PSI. It seems the Endo (flatter section) would be more consistent at self-steering across a wide pressure range. A rounder profiled tire would have less self-steer at higher pressure and more self steer and lower pressure than a flatter profiled tire. Just my 2, FWIW.
    Last edited by JR Z; 02-03-2012 at 07:38 AM.

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