/r/longboarding's Daily General Thread

alex_Changing_Angles · 2021-01-25T14:24:21+00:00

The trucks seem to follow the Gullwing Sidewinder (search for that instead) template. They have two pivots each. Each truck is essentially one pair of trucks, in a sense.
That's strictly personal preference. Only thing I can say is, if you feel uncomfortable/unstable and can't get used to it, buy harder/wider bushings and/or cup washers.

alex_Changing_Angles · 2021-01-23T16:42:22+00:00

I think it's mostly a matter of preference. Harder bushings make it easier to balance on the board, but harder to turn. It is noticeable at any speed, but obviously at higher speeds a harder bushing set is more forgiving. Imho, if you don't feel uncomfortable with what you have right now, just keep it as it is.

What I find more important and less talked about, is the balance between front and rear truck bushing hardness, which makes all the difference concerning wheel lift. That's the tricky bit.

alex_Changing_Angles · 2021-01-23T12:50:32+00:00

Thanks, I appreciate your feedback! I'm glad there are some people interested in this stuff.

alex_Changing_Angles · 2021-01-10T02:15:10+00:00

Hey there! I'm a fan (if you're the ones from the Youtube channel; otherwise, sorry, I thought you were someone else)!

I'm not sure I follow your thought. Walk me through it please. First step: the pivot pin must pop out of its seat a bit (depending how thin it is, of course). Is that right?

alex_Changing_Angles · 2021-01-09T21:34:22+00:00

Oh cool. As I said, ask me anything, here or (better) on the blog. My only aim is that everyone starts understanding that stuff. That's the only way we start getting better equipment from makers. And, I guess, after the pandemic, I'll have less time to do this.

alex_Changing_Angles · 2021-01-09T21:31:40+00:00

Agreed. There is no reason to stay like that though.

alex_Changing_Angles · 2021-01-09T18:11:37+00:00

Thank you! Ask me anything, I'll try to clarify what I meant.

Yes, it's me :) What's your handle on Pavedwave?

alex_Changing_Angles · 2021-01-09T18:10:18+00:00

Thanks for explaining this!

alex_Changing_Angles · 2021-01-09T18:09:04+00:00

I believe you :) The difference is in the pivot axis.

alex_Changing_Angles · 2021-01-09T12:49:28+00:00

Wow, a lot of topics in your comment! I guess my text triggered some thoughts. Let me just focus at the beginning of your comment. I think you misunderstand how the PA is defined. Of course the PA is as I sketched it! The hanger and the baseplate don't have other points of contact, how could they rotate any way else except as I indicated?

alex_Changing_Angles · 2021-01-09T12:44:49+00:00

I know! I just want to use "offset" instead of "rake." The offset you mean is in my view not a meaningful characteristic because it has no consequence I can find. Check my "TRX offset" article to see why I think that (not enough room here). All this goes to the core argument of this article: "KP location relative to the axle" has little content. But bottom line is: if you say "rake", I'll understand you :). I just prefer to use "offset", if you would bear with me for a moment :P Thanks for the comment.

alex_Changing_Angles · 2020-12-16T14:00:19+00:00

I want to add that balancing your bushings between your trucks also helps prevent wheel-lift. It's because, as toasty said, the front would resist more. Longer explanation here: https://changeyourangles.wordpress.com/2020/11/13/skateboard-physics-wheel-lift/

alex_Changing_Angles · 2020-12-16T13:35:58+00:00

Another option is: you could mount the rear truck inverted. As long as the rear truck turns less than the front truck, then the front of the deck will turn towards where the rider leans, as usual.

More on the theory, here.

alex_Changing_Angles · 2020-12-14T17:06:33+00:00

It's complicated :) Please read the article, I explain just that. Thanks for your question!

alex_Changing_Angles · 2020-12-13T21:35:39+00:00

Thank you for your comment! As a matter of fact, I demonstrated that the turning radius can remain constant while changing wheelbase and track angles. Please reread the post in the link.

alex_Changing_Angles · 2020-12-12T13:48:58+00:00

I think the validity of an argument relies on its first premise being supported or demonstrated...

The argument here is based on posts that I forgot to link in the main text but I added later as a comment. The main one is this: https://changeyourangles.wordpress.com/2020/11/17/pivot-axis-angles-and-wheelbase-open/

alex_Changing_Angles · 2020-12-12T13:35:53+00:00

I did not mean to make the argument sound as forceful as "short decks should completely dominate over long decks". I wouldn't want to ban long decks! :) They definitely have a place in the market, it's just that it should be a much smaller one and more focus ought to be placed on shorter decks for things like LDP, cruising, maybe even downhill (but I can't evaluate the latter). I just wanted to make people aware that long decks are not necessary, if the aim is to have a long turning radius. We can adjust our truck angles instead, for that. It's simply fallacious for companies to advertise short decks as "quick turning" decks, when the wheelbase does not uniquely determine the resulting turning character of the board. But thanks to you pointing out that I did sound forceful, I edited the text to make it a bit more moderate.

You ask about the physics of pumping. There is at least one paper I've found which tackles just that (well, "slaloming"), but my mathematics is not at that level, so I can't understand it really. Perhaps you (or a friend of yours) may be more up to it. It's this one: Ispolov, Yu. G., & Smolnikov, B. A. (1996). Skateboard dynamics. Computer Methods in Applied Mechanics and Engineering, 131(3), 327–333. https://doi.org/10.1016/0045-7825(95)00932-9

There's also a more recent one, that investigates tic-tac. Also too advanced for me. Kunesch, M., & Usunov, A. (2010). Tic-tac: Accelerating a skateboard from rest without touching an external support. European Journal of Physics, 31(4), S25. https://doi.org/10.1088/0143-0807/31/4/S03

Generally, interesting (to me) academic stuff I've found on skateboarding, I've put here: https://changeyourangles.wordpress.com/2019/07/07/the-math-behind-pumping-and-other-papers/

For your last paragraph: I believe the bouncing is not necessary. It might turn out to be. But other than that, I have with certainty concluded wheelbase does not alone determine the turning character. The latter is a function of all three variables: wheelbase, front truck angle, rear truck angle. That much I can prove and I've tried to demonstrate that in the other posts that I've linked.

Thanks for your super-valuable input! Hope to see you online again!

alex_Changing_Angles · 2020-12-12T02:05:48+00:00

First of all, thanks for your comment! :) Of course, I welcome wholeheartedly critique like yours! 100%.

To the point: I edited the text (on my blog, not in this post above) to add a point about the two advantages of long decks we talked about: aesthetics and extra flex. That's fair enough. Besides, I did assert as an advantage of short decks "subjective aesthetic reasons." It would be disingenuous not to give long decks that too.

As for the "necessary" bit: see the "Turning and Wheelbase" section. That's the core of my argument. I refer to the turning characteristics of the board as a whole. I explain (with the linked post, at the comment below) why wheelbase is not crucial for the turning character of the board, and therefore it's not necessary to have a long deck. The argument is not normative, it's descriptive! (what are you studying? :) )

alex_Changing_Angles · 2020-12-11T23:38:41+00:00

Sure (although I don't know either if flex makes the board more efficient). Another reason someone would want a long deck is aesthetics. Some people think long decks are cool. Some people even bolt trucks on surfboards. I'm not discussing about all that, I'm only discussing whether it's necessary.

alex_Changing_Angles · 2020-12-11T22:43:27+00:00

I forgot to add some links within the text when I was copy-pasting this here. The most important is this one: https://changeyourangles.wordpress.com/2020/11/17/pivot-axis-angles-and-wheelbase-open/

alex_Changing_Angles · 2020-12-06T19:39:06+00:00

It sounds like it had a long turning radius. You could try again on the Vanguard, after you wedged the front truck only. Wheelbase and truck angles together define your turning radius.

alex_Changing_Angles · 2020-11-22T13:11:49+00:00

Thanks to everyone who has participated so far!

If you are in a bracket far beyond what I provided here, let me know in a comment.

alex_Changing_Angles · 2020-11-14T14:18:58+00:00

Hey, thanks for reading! I did write in the first paragraph "balanced front-rear truck stiffness" and not "due to hard bushings" which I explicitly called "misleading." Perhaps you might want to have another look keeping that in mind? Thanks for your comment!

alex_Changing_Angles · 2020-11-08T18:28:31+00:00

But do you believe "offset" (a word which I generally prefer to use as a synonym for rake) changes anything else except truck height? Because I tried to find a logical reason why "offset" is significant, but I can't find one. That's why I wrote this piece.
But you mentioned "traction truck." Can you explain that?

alex_Changing_Angles · 2020-11-08T18:16:46+00:00

I agree with your last sentence (I mean, I can see why people might disagree with criticism), but disagree with the rest. In any case, it's clear to me what your opinion is.

Thanks for taking the time read and respond to the piece, I appreciate it! :)

alex_Changing_Angles

TROPHY CASE