Check out the big brain on Mike! Over at Northwest Skater You can find a discussion of a method for calculating the size of a transition radius using a three-foot straight edge and a short ruler.
Basically you put the three-foot stick on the transition and measure the space under it at the center. Then use math to work out the radius from there. You need a straight stick because inaccuracy in your measurement will be magnified in your calculations but that isn’t probably a huge problem, I’ve seen those guys cut their transition templates with a chainsaw.
They also provide a handy table that lists common radii for various values of h.
10 comments
Be a Good Daughter
Nice post.
I guess you’ll read my blog..
Sayonara
sheltered
No, no, no, not tranny templates. I want an adjustable pole with a cable and plumb bob so I can cart around a giant compass on the top of my car when I skate.
Dan Hughes
Ha ha ha ha….laughing too much… 🙂
Gene
Yeah, I typically wear pads + helmet, and carrying around a stack of inverse tranny plywood on top of my regular gear would be too much. They don’t have skate caddies do they? haha
sheltered
I talked with Mike while at a session when he was figuring it out. It is pretty cool. Fairly simple geometry. You’d think that there would need to be a π(pi) in there somewhere but there isn’t.
hass
Finally someone did something useful with math.
You could make the measurements less sensitive to error by using a larger stick. This would help eliminate the 1/16th of an inch difference between 9 and 10 foot tranny.
Dan Hughes
Or you could just skate it! Ha ha ha!!!
Funny Mark. That’s the point though, we skate everything, but knowing the tranny is important to geeks who want to know.
And this method while not perfect, is at least a little easier than carrying around a bunch of inverse templates.
Gene
Another way might be to take pieces of “inverse tranny” with known transitions (i.e. the plywood that is left after the templates are cut) and use those as a guide to estimate the transition of the surface in question? Just press them up to the surface and see if the inverse template is too curvy or too straight.
Sam
Yea mathematics. Here is the calculation to loop Hailey’s full pipe:
http://www.skateoregon.com/Science/Idaho2.html
(cliff notes sez answer is: 23 mph)
sheltered
Mike does have a PHD in math. I used to call him Dr. Skate, but soomeone else was using that handle on the boards. I call him DR. Stoke now. He’s full of energy.
Yeah its kind of precise. I don’t think I’ve every heard the term micro-kink, but maybe it now applies.