Contents

Write-ups of math/logic problems related to how skateboards work are categorized under “math.” In a rather more empirical direction, posts in which I look at particular attributes of specific (groups of) products are labeled as “data.” Texts in which I try to understand and describe the inner workings of the skateboard community, labeled “sociology,“ and the skateboard industry, labeled “political economy,“ are bundled together. The former are more theoretical, while the latter typically contain more empirical observations. The “index,” i.e., the blog’s tags, might be useful to you, as I try to keep it concise and updated.


Math

Skateboard physics: wheel lift

In this post, I argue it’s essentially the difference in stiffness between the rear and front truck that causes wheel-lift. A shorter axle makes wheel lift more probable by placing the possible axis of rotation (of the wheel-lift) closer to the middle of the board (and therefore the rider’s weight further out from that axis). However, balanced front-rear truck stiffness would make wheel lift impossible, by placing that axis entirely out of reach for the rider’s weight. Continue reading Skateboard physics: wheel lift

Skateboard physics: moment of inertia

Understanding which forces are at play when the axle rotates on the ground is a pesky problem of mine. The goal is to obtain a good understanding of the effect that different axle lengths have when turning (an effect that’s overstated, I feel, in the community). It turns out the problem is not so unattackable. In this post, I report what I’ve found so far. Continue reading Skateboard physics: moment of inertia

Skateboard physics: squeezing bushings

Occasionally, people assert that TKP trucks (i.e., trucks with significant forward rake) turn “progressively,” while RKP trucks (i.e., trucks with minimal rake) turn more “linearly”. That, at first glance, can only mean that the trucks resist turning in such ways. In this post, I check for patterns in the way trucks resist when a rider leans on a skateboard. Continue reading Skateboard physics: squeezing bushings

Board height: does it matter?

Why I think board height doesn’t matter (in absolute terms – i.e., efficiency, acceleration etc) and if it did, lower would be better. The “top mount offers more leverage over the trucks” argument is void. The rider on a dropped deck is closer to the pivot axis of each truck. Therefore, the lever is shorter. … Continue reading Board height: does it matter?

Truck width: wheel travel

In this, I explain why the wheels travel the same distance, regardless of truck width. The main point is that the circumference of a circle is directly proportional to its radius. So, a circle with a radius x-times as long as another circle will also have x-times the circumference. So, the wheels trace curves of equal length on different truck widths. Continue reading Truck width: wheel travel


Data

Curfboard Model

Curfboard: a closer look

Curfboard is a simple but ingenious design, which shows that innovation can still happen in an oligopolistic, stale market. It would be better though if Curfboard’s marketing steered clear of speciousness and didn’t thus undermine its own reliability. Continue reading Curfboard: a closer look

TKP trucks: history and quirks

The TKP template has been with us entirely unchanged for many decades, during which materials technology and consumer needs have evolved. However, some things that are characteristic about TKPs are not also essential. In this post I want to examine two ubiquitous but not defining characteristics of TKPs, which truck makers ought to reconsider. Continue reading TKP trucks: history and quirks

Survey: Effective Foot Platform

I’ve been thinking lately about the deck’s so-called “effective foot platform”, but I needed to know how we (not just me) in LDP are standing on our boards. So I’m making a survey and the question of the survey is about how wide your stance is. If you could take the time answer, I’d appreciate … Continue reading Survey: Effective Foot Platform

Misaligned pivot pins

Most TKP trucks are built with their pivot pin not parallel to the pivot axis. What exactly happens with the interface pivot pin – cup when the truck turns and the pivot pin unavoidably binds with the pivot cup? Continue reading Misaligned pivot pins


Sociology & Political Economy

COVER_for_Ultraskate_2021

Ultraskate 2021 amidst a pandemic

In early 2021, while the covid-19 pandemic was still raging, and after many events had had to be canceled or postponed in the struggle against the spread of the disease, the IDSA decided to hold the Ultraskate event in Miami anyway. This decision can only be explained by weighing the interests involved against each other (of which public health interests are part). In this post I try to reappraise this conflict of interests to the best of my available resources. Continue reading Ultraskate 2021 amidst a pandemic

Image credit: https://cpwskate.blogspot.com/2012/01/bennett-vector.html

The case against Bennett Vector

You are rightly frustrated with hearsay and anecdotal “evidence” distorting consumer preferences and pointing them to inferior products. Logic doesn’t seem to help and in fact the parties involved are inclined to prefer hearsay over logic. The perfect example of this is the Bennett Vector truck. Continue reading The case against Bennett Vector

Brain bugs II

I stumbled upon the following tweet-storm the other day. It’s just too relevant to what I see in the longboard community not to post: “We lie to ourselves all the time. In fact, our thinking processes evolved to help us lie to ourselves about the facts around us. Why? Because being accurate about the world around you was often less important than agreeing with the people around you.” Continue reading Brain bugs II

Dont Trip Bhanger product page showing it was sold with PU pivot cup

You tripped up again, Dont Trip

It is my impression after all these years of following this community, that all this company cares about is milking the enthusiasts who would pay for any of their new shinny products and taking advantage of the ignorance of beginners. Here’s a couple of instances that illustrate this point. Continue reading You tripped up again, Dont Trip


Index

Axle Axis Axle Offset Balance line Bennett Vector Bushings Carver Trucks Curfboard Dont Trip GBomb Hanger Width KP/PA angle Loaded Boards Major Arc Pivot Axis Rake Randal Trucks Riptide Roll center Sabre Trucks Skateboard deck SkateIDSA Speed Wobbles Surf-Rodz Tracker Trucks Turning Radius unfinished Wheelbase