Measure a sidecut radius by hand?

[NoWeddings.com]

The Prior 175 I have for sale has undergone intense scrutiny sparked by a false spec sheet.

I confirmed the length by holding the tape taught from tip to tail. (Flat on the board only gave it another 1/8".)

I found the narrowest point on the base and confirmed it with spec.

Got me to thinking... Anybody got a process for figuring the overall radius of the sidecut using a tape measure and brains?

I can easily get difference in widths from narrowest to fattest, AND the distance between the two fattest... Is there a geometric equation to take me to radius from here?

Thanks

[tex1230]

there are a few calculators around - you need running length, tip/waist/tail width. http://www.natew.com/pages/software/snow/html.Reverse

[D.T.]

I have tried Nate's site several times recently and all I get is a server not found message.

[r_starr]

This is the formula I have to calc sidecut radius:

((Running_Length^2/4 + (Tip_Width-Waist_Width/2)^2) / (2*Tip_Width-Waist_Width/2))/100

Appears that the formula may need to be tweaked for a board that has taper. Rob

[BlueB]

For the tapered boards add tip and tail width and devide by 2. Use that as corrected tip width.

Nate's callculator seems to be down. I could draw it up on cad quickly if you posted tip, tail and waist widths and contact length.

I can bett this would end up as ~12m scr, stock spec of 175...

[pebu]

Oh, gosh... I'm an engineer, and I hate doing calculations like that... That's what they make computers for..

Use a solid modeling or drafting program... Or give the specs to somebody who has access to one of those... I'll help you out as soon as I can get my solidworks to come back to life (it's frozen right now... I don't want to close it down cause I have crap that I didn't save yet...)

Go to www.grafsnowboards.com and download his snowboard design tool. It runs on java and it's a really neat program. It might take some tweaking, but you should be able to get the general shape with all the important measurements and it should tell you the rest..

[D-Sub]

Noweddings

Im guessing, but pretty sure, that the specs have stayed the same except for length. The 187 is exactly the same as the 185 I have except for the 2cm of length which is most likely just due to the newly standardized rounded tails

World Cup Race Specs

<!-- begin specs --> <table class="boardSpecs"><tbody><tr class="shaded"> <td>

</td> <td>

</td> <td>

</td> <td>

</td> <td>

</td> <td>

</td> <td>

</td> <td>

</td> </tr> <tr class="shaded"> <td class="rowHeader">Length (cm)</td> <td>157</td> <td>163</td> <td>169</td> <td>173</td> <td>177</td> <td>183</td> <td>187</td> </tr> <tr> <td class="rowHeader">Effective Edge (cm)</td> <td>130</td> <td>136</td> <td>142</td> <td>146</td> <td>150</td> <td>156</td> <td>160</td> </tr> <tr class="shaded"> <td class="rowHeader">Nose Length (cm)</td> <td>21</td> <td>21</td> <td>21</td> <td>21</td> <td>21</td> <td>21</td> <td>21</td> </tr> <tr> <td class="rowHeader">Tail Length (cm)</td> <td>6</td> <td>6</td> <td>6</td> <td>6</td> <td>6</td> <td>6</td> <td>6</td> </tr> <tr class="shaded"> <td class="rowHeader">Nose Width (cm)</td> <td>24.7</td> <td>24.6</td> <td>24.6</td> <td>24.5</td> <td>24.4</td> <td>24.7</td> <td>24.4</td> </tr> <tr> <td class="rowHeader">Tail Width (cm)</td> <td>24.3</td> <td>24.2</td> <td>24.2</td> <td>24.1</td> <td>24</td> <td>24.3</td> <td>24</td> </tr> <tr class="shaded"> <td class="rowHeader">Waist (cm)</td> <td>19.5</td> <td>19.5</td> <td>19.5</td> <td>19.5</td> <td>19.5</td> <td>19.5</td> <td>19.6</td> </tr> <tr> <td class="rowHeader">Radius (m)</td> <td>9</td> <td>9.8</td> <td>10.6</td> <td>11</td> <td>11.9</td> <td>13</td> <td>14</td> </tr> <tr class="shaded"> <td class="rowHeader">Taper (mm)</td> <td>4</td> <td>4</td> <td>4</td> <td>4</td> <td>4</td> <td>4</td> <td>4</td> </tr> <tr> <td class="rowHeader">Insert Setbacks (cm)</td> <td>2.5</td> <td>2.5</td> <td>2.5</td> <td>2.5</td> <td>2.5</td> <td>2.5</td> <td>2.5</td> </tr> <tr class="shaded"> <td class="rowHeader">Stance (in)</td> <td>17"-22"</td> <td>17"-22"</td> <td>17"-22"</td> <td>17"-22"</td> <td>17"-22"</td> <td>17"-22"</td> <td>17"-22"</td> </tr> <tr> <td class="rowHeader">Suggested Rider

Weight Range (kg/lbs)</td> <td>40-65/

90-150</td> <td>50-85/

110-190</td> <td>55-90/

120-200</td> <td>60-95/

130-210</td> <td>60-95/

130-210</td> <td>65-105/

140-230</td> <td>70-110/

155-240</td></tr></tbody></table>

[Jack M]

Older Prior 175s had an 11.5m radius, now they're 11.9m. If you still question it, you can use the 3 point formula already posted. However it's a good thing Prior's are radial, because the 3 point formula doesn't work for elliptical or parabolic or anything else.

I know this, because doing the 3 point calculation on my Madd 180 came up with 14m. I <i>know</i> this is false, because it rides longer than a 15m board I used to have. Madd estimates 16m, and that feels more like it.

Taper will mess you up too, because the narrowest part of the board will not be the midpoint of the arc. But 4mm isn't much, so you should be able to get a number that is pretty close to accurate.

[Jrobb]

This one I got off some skiing site.

To unlock the sheet, password is "sidecut"

J

PMSidecutRadCalc.zip