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.
The basic idea I’d like to convey with this post is that a skateboard always balances on the line that connects the two centers of the axles of the trucks. Continue reading Skateboard geometry: balance line
In this post, I want to make the case for a turn to shorter decks. First, I explain why long decks are redundant, then I enumerate the advantages of short-wheelbase decks and finally I attempt to answer exactly how short decks should/could become. Continue reading Wheelbase: the case for short decks
Wheelbase and truck angles are directly related. I want to show that the three variables: front and rear angles and wheelbase are sufficient and necessary to determine the turning radius of a skateboard, when tilted a given amount. Continue reading Pivot axis angles and wheelbase (open access)
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
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
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
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?
“Get a narrow rear” is often given as advice in internet communities for LDP. Is this a relic of the dark ages of skateboard geekery, or is there a valid LDP/slalom-related reason behind it? I investigate. Continue reading Rear hanger width: does it matter?
In this entry I want to write down a couple of things that relate to a project that might or might not happen in the future. It’s an idea by a friend (whose handle is “Holden”), who already built a few two-spring trucks. His dream was (still is) to built a one-spring truck. Continue reading Skateboard physics: one-spring truck (and the dead-zone problem)
This post is to show, in very practical terms and without abstract models, that reversing the rear truck is simply an option available for when we need it, not some fanciful eccentricity. I derive a very simple rule-of-thumb for those keen to experiment. Continue reading Turning radius: as a function of the rear PA angle
Here’s a couple of illustrations and a chart just to restate the obvious: tilt/turn is rake-agnostic. Continue reading Axle offset (aka rake): it doesn’t change axle turn
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
I have been thinking about truck geometry lately and I re-read Neil Carver’s article with more attention. The thing is, the article is dead wrong about what a positive/negative trail is. Continue reading Trail: Carver’s article “The science of the speed wobble”
The other day I was searching the internet about “rake” and speed wobbles and stuff and I stumbled upon Sabre’s webpage on “Truck Geometry.” It was a bit… messy. Continue reading Axle offset (aka rake): urban myths and skate companies
What happens when you reverse the rear truck? Nothing much. Reversing is de-wedging and that’s all. Continue reading Rear PA angle: inverted rear truck
So, yeah, it exists! The pumping motion is described by these Russian mathematicians (and I must assume, avid slalomers).
The math exceeds me by far, but someone, somewhere, sometime might find this helpful, hopefully. Continue reading Peer-reviewed literature: the math behind pumping
A fantasy steam punk machine which looks kinda cool, if that’s your thing, until you realize it can’t possibly exist, because it violates the laws of nature and logic. Continue reading Stooge 3-link truck: skating in never-never land
The Torsion Tails are a line of rear trucks made by GBomb specifically for platform decks. In this post I examine the design. Continue reading GBomb’s Torsion Tails: 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
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
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
In this short post I look in more detail at the Tracker RTX Offset truck (which I believe has been discontinued). I discuss the reasons why I consider it a pointless exercise in truck design. Continue reading RTX Offset: axle intersects KP – why, Tracker?
I’m skeptical about whether companies are indeed creating their own compounds. Their own molds and shapes, pigmentation and logos, sure. But don’t they still have to buy it in liquid form from somewhere?
So, I started a thread on a forum and I got into a rather interesting conversation with user Zip, which I reproduce here. Continue reading Polyurethane (PU) products and the industry
Sociology & Political Economy
Lena Meringdal, deck maker and distance skating athlete, talks about her skate brand, MelonenKacke Longboards. This interview covers her brand’s story, lineup, R&D and marketing strategy. Continue reading MelonenKacke: interview with Lena
The distance skating scene is a small insulated social world that includes all the main spheres and dynamics one sees in an oligarchic market polity. Continue reading The distance skating scene: a miniature market oligarchy
Is LDP a kind of skateboarding, or does it belong under the distance skating umbrella? In this post, I make an effort to define this sport. Continue reading The roots of LDP: distance sports or slalom?
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
I don’t know where the problem starts. Is it the consumers who would buy, literally and figuratively, anything? Or is it rather the skate companies who would sell to the consumers anything, if they asked for it? It certainly is a vicious circle. Continue reading Why we’re stuck here: on the state of the skate industry
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
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
I stumbled upon two research papers that discuss the involvement of middle-aged males in skateboarding. They helped me get a better understanding of the conservatism of members of the community on various equipment-related topics. Continue reading Skateboarding and the ‘Tired Generation’
A short video survey of landmark skate spots and their significance for (rather: signification by) skateboarding by Vox. Continue reading Skateboarding and urban/industrial architecture
Disclosing affiliates and partnerships in the social media before posting promotions disguised as innocent suggestions is self-evident. Or so I thought. Continue reading Unethical practices in skateboard forums
“Safety regulations against skateboarding can impede commuters and threaten the idea of complete streets.”
I stumbled upon this interesting article and I reproduce here in its entirety, until somebody complains. It was published on Transfer Magazine. Continue reading Faster than walking, more flexible than biking: skateboarding as a real mobility mode
Skateboards with women’s names, trans women being unwelcome, discriminatory advertisements. Skateboarding is still a boys’ club, no doubt. Continue reading LDP is a boys’ club: sexism in the forums
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
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