Jump to content
Note to New Members ×

Sidecut vs Effective edge


abakker

Recommended Posts

the two lengths i am looking at are the 163 and the 166

Sorry, I don't have anything to add for the SCR discussion,

but for what it's worth. here's a mini gear review.

I too am questioning whether to purchase the 163 or 166 F2 for next season.

Just last night I demoed the 163. I'm 6'5" and ~220lbs.

Free rode some turns, then took it into a very tight SL course -

gates set apart at ~ 9-10m.

The board and I didn't do so well on the tighter turns, but was a good test

to see what we were capable of. Was very quick edge to edge, and

released from the turns with ease - also held very well on hardpack

conditions and chunks.

It rode "Bigger" than I expected it to. Because it was so much stiffer

than my previous SL boards (current is Burton FP 164 11m), I am

curious if this model requires some extra ride time to "wear-in." Dunno..

All-in-all, I thought it was a very tasty board. Will be getting one, but

still undecided about 163 vs 166. I wish I knew if there was a

dramatic difference in stiffness between the two.

Really hope to try it again this next week on a somewhat regulation course.

Link to comment
Share on other sites

Thanks BlueB and Nate for the in depth replies. Thanks Jrobb for doing the paper test. I see your point, but my results were different. I am sure that user error is involved here somewhere. Most of all, thanks for my new paper snowboards. I printed them on card stock to make them more durable and easier to work with. I also glued wedges on both of them to give them the same tilt angle.

It still seems like the longer board is a tighter arc. The center of the longer board sits behind the arc of the shorter while tip and tail cross that arc seemingly making a tighter arc - the shorter arc is covered up by the longer board.

In any case, you have challenged me.

Until we move to a new house, I cannot get my reference materials out of storage. With the arguments that you have made, I will concede that I may be misreading or misunderstanding the whole thing. I would still like further proof. The board lengths and sidecuts from the manufacturers still seem to support my argument.

Thanks again for the good discussion.

As far as the F2 SL 163 vs. 166. If you are big and heavy - like me (Scuff - I have one inch and 10 pounds on you), go for the 166 - it is a no brainer. I have had and still have models of both. They perform very similarly, only the 166 is definitely more stable. As you have found, there is no comparison to a Burton FP.

Link to comment
Share on other sites

http://www.natew.com/pages/software/snow/SnowboardCalculator.txt

That's the source code behind the web calculators.

About a third of the way down the page is a function called SolveForCarve that gathers the parameters from the form and computes the carve radius (then it goes on to compute the ideal speed for that radius). Currently it computes the radius by looking at the sidecut depth and edge length, then figuring out how much the board has to bend to stay in contact with the snow at the given edge angle. (Imagine a triangle where two points are at the ends of the effective edge, and the third point is in the middle of the effective edge.) Finally, it finds the radius of the circle defined by those three points.

In the comments you can see that I also tried computing the carve radius based simply on the sidecut radius and the edge angle. The results were the same.

Link to comment
Share on other sites

I like good constructive discussion, too. This is a great tread - no one is flaming anyone, and hopefully we all come out of it with deeper understanding of how the things work.

Phil, one last test with my 3 boards: cut them out just as they are, overlaped in one piece, so you end up with the cutout of the biggest board with the drawing of the 2 smaller ones on it. Then tilt to any angle you want and see if they are all on the same arc...

As for the increasing scr on the longer lengths on the boards of the same type, I've got a theory, actually couple, but I need to think it through a bit more...

Link to comment
Share on other sites

Coiler infiltrator. length 161 .. sidecut 14m.. running length 151 wooo hooo

It defize all logic! Don't need long boards any more.. bruce made two! most people who ride it can't believe its 14m.......

Rode it again today.. and I must say .. it the fizishle but Im hoping others who have riden the duplicate can chime in...

It boggles your mind but it rides so good you can't get past the 161 length..

How do you say. In MASS words.... "Wicked stupid"

:smashfrea

Link to comment
Share on other sites

Attached is an illustration with 3 overalped boards. Print, cut out and try at any inclination - they'll aways be at the same arc...

This makes sense to me. So is there much of a disadvantage in a longer board, keeping all other things the same....kinda like the Donek FC 171 vs the 179? I know the 179 is a little stiffer but let's just assume you can flex either board....and let's assume we're carving all of the time. Wouldn't you gain some stability, maybe some edge hold? But what's the disadvantage?

Link to comment
Share on other sites

To answer the original question, sidecut radius is more important when deciding how a board will turn

However Phil is on to something here. The equation:

turn radius = sidecut radius * cos(edge angle)

is a simplification. This would dictate that our boards take on a shape that is a "projection" (think: shadow) of the sidecut onto the snow when we tilt it up on edge. However that is impossible, because as Sean Martin once pointed out to me, our boards do not change length. The projected curve does change length. As a result, the nose and tail of our boards must "pinch" in by some amount. That is, the nose and tail are somewhere inside the projected curve. This is why our tracks left in the snow have some width to them.

I would not be surprised if a longer board with the same sidecut radius as a shorter board produced more of this pinch effect.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



  • Recently Browsing

    • No registered users viewing this page.
×
×
  • Create New...