Changing Angles

Featured

Theory

Truck geometry

Skateboard trucks, despite their variety, follow a simple principle: a baseplate and hanger rotating around a fixed pivot axis. This article breaks down their geometry, explaining how tilt translates to turn, the role of axle offset, and other fundamentals. Areas that need further research are also pinpointed. Alongside terminology discussions to cut through skate jargon, the post uses plenty of illustrations to visualize key ideas.

Analysis

The case against Bennett Vector

An account of the debate about the merits of the Bennett Vector truck—a controversial piece of LDP gear. It covers the truck’s technical flaws, the so-called “magical” performance that some attribute to nostalgia, and the ritual of modifying it that has become part of its cult status. The article concludes that the Vector’s continued popularity is driven more by myth and sentimental attachment than by real performance, urging readers to look beyond the folklore.

Theory

Turning radius: pivot axis angles and wheelbase

This article examines the interplay of three essential parameters—front truck angle, rear truck angle, and wheelbase—on skateboard turning behavior. Animated examples and elementary geometry illustrate how these factors collectively determine the turning radius. The article offers practical guidelines for adjusting setups when changing decks, ensuring a consistent ride despite modifications in geometry.

Analysis

0° trucks: substance and hype

Zero-degree trucks have become hallmarks of the long-distance pumping community, but does the number itself hold real significance? This article dissects their perceived advantages, overlooked downsides, and the hype-driven forces behind their popularity—ultimately revealing that their appeal rests not on performance, but on the power of a round number.

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Theory

The concept of ‘Gearing’ in skateboard pumping: a case for precision

What might the idea of “gearing” describe in skateboarding? Should it be a catch-all phrase, or could it connote a simple, usable concept? I argue for the latter.

Skateboard geometry: balance line

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.

Ideal truck angles

How do we decide which angles our trucks should be wedged to? In a post addressed to beginners, I propose a process and explain the reasoning behind it.

Wheelbase: the case for short decks

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.

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…

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…

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.

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. The lever to do what exactly? To…

Rear hanger width: 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.

Skateboard physics: one-spring truck (and the dead-zone problem)

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.

Turning radius: as a function of the rear PA angle

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.

Axle offset (aka rake): it doesn’t change axle turn

Here’s a couple of illustrations and a chart just to restate the obvious: tilt/turn is rake-agnostic.

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.

Trail: Carver’s article “Speed wobble hunting”

Years ago, Neil Carver’s 2011 Concrete Wave article on speed wobbles struck me as credible. Revisiting it with fresh eyes, however, revealed a fundamental error: the article misdefines trail, a cornerstone concept in truck geometry. This article is an appeal for a modicum of literacy from the industry.

Rear PA angle: inverted rear truck

What happens when you reverse the rear truck? Nothing much. Reversing is de-wedging and that’s all.

Peer-reviewed literature: the math behind pumping

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.

Analysis

Stooge 3-link truck: skating in never-never land

A contraption that might as well have been a cute robot from a low-budget sci-fi film. It’s meant as a serious truck though. In the article, the truck’s design is dissected. By modeling its fixed joints, it is revealed that the truck’s geometry makes turning physically impossible. The piece exposes impractical engineering and inherent absurdities,…

GBomb’s Torsion Tails: a closer look

The Torsion Tails are a line of rear trucks made by GBomb specifically for platform decks. In this post I examine the design.

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.

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.

Major Arc: a couple of major problems

Major Arc is marketing a design that isn’t, and never could be, geometrically consistent. In this article, I explain what makes the design unworkable. The real question is whether they already knew about this.

RKP – TKP: term pertinence

In this short post I want to explain why I think the terms “TKP” and “RKP” do not really tell us much about how trucks work.

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…

RTX Offset: axle intersects KP – why, Tracker?

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.

The BS-marketing collection

My little collection of skateboard industry marketing bullshit I’ve stumbled across on the internet in the last few years. It’s a work in progress.

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?

Axle offset (aka rake): urban myths and skate companies

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.

About bushings

I examine a few things about bushings that keep coming up in skate forums: Wheel-lift, Sizes, Shapes, Mixed duros, etc.

KP/PA angles

Just for future reference, I measured the KP/PA angles of a few popular trucks. Here’s the results.

Ideas by other people

While the industry is rather unimaginative, over the years I’ve stumbled upon quite a few brilliant non-professionals. I’ve collected examples of their work in this post.

Bennett axle offset (or “rake”)

Someone on facebook answered me that it’s 22mm, perhaps a tiny bit more.

Sociopolitical

Brain bugs: a look at why we resist new ideas

“It made more evolutionary sense to be wrong with others than it is to be right alone.” Skateboard forums resist change and gatekeepers enforce outdated practices while dissenting views are dismissed or suppressed. This article explores how “brain bugs” like confirmation bias and motivated reasoning stifle progress, urging community members to embrace deeper critical thought…

The reality of PU manufacturing: a dialogue on industry practices

I’m skeptical about whether companies are indeed creating their own polyurethane compounds. Their own molds and shapes, pigmentation and logos, sure. But don’t they still have to buy it in liquid form from somewhere? After a discussion with a purported industry insider, I remained doubtful.

Cops on skateboards: not cool

Which is true? A. Skateboarding makes the police cool, or, B. The police makes skateboarding uncool? By adopting skateboarding’s surface-level coolness, police defuse its countercultural significance. The piece argues why maintaining skating’s radical edge matters when institutions attempt to absorb and neutralize its subversive power.

MelonenKacke: interview with Lena

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.

The distance skating scene: a miniature market oligarchy

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.

The roots of LDP: distance sports or slalom?

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.

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…

Why we’re stuck here: on the state of the skate industry

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.

Skateboarding and the ‘Tired Generation’

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.