The Curious Design of Skateboard Trucks
bedelstein.com
bedelstein.com
This guy is also awesomely creative in skateboarding and in video creation.
I remember seeing the tapes he did with Mullen back in the early 00s, there aren't many people you could put on screen with Mullen but he is one of them.
Kingpin angle affects cornering ability. Kingpins at higher angle from vertical corner more sharply, so skaters doing figures tend to prefer more vertical kingpins than dance skaters, who want to be able to do deep curves. For instance, kingpin angle is the major difference between Snyder Super Deluxe and Imperial plates.
Durability is a serious consideration for roller skating kingpin angles. It's painful when a kingpin breaks and more common with less vertical kingpins, so most skaters doing freestyle will choose a plate with kingpins closer to vertical. Roller skate plates also often have a "jump bar" connecting the two trucks to decrease the chance that a kingpin will break when a jump is landed. Sometimes even a jump bar breaks.
Longboards use larger wheels and wider trucks to clear the board of any wheel bite. Some even cut out that area of the board. For skateboarding, you need that area for stability, flip tricks, and landings.
The physics of it all is what’s so awesome about it.
Good quality skates have pivot pins whose length is adjustable. I don't know if skateboard trucks generally have this feature.
You tighten and loosen the pressure on the kingpin rubber bushings by shortening and lengthening the kingpin in order to adjust resistance for cornering. When you do that, you also need to be able to adjust the length of the pivot pin. Otherwise, lengthening the kingpin results in a pivot pin that's not resting properly in its cup. You want it just touching, not floating out of the cup or exerting a lot of pressure on the cup.
Good quality roller skate truck pivot pins end in a spherical ball and the pivot pin cup on the truck is also spherically machined. There's no bushing in the cup.
On a more practical aspect, you don't want to relearn the feel of your trucks, and for what benefit, if the word was they grind better, or are lighter without a reduction in strength, maybe, but neither are likely to be more than marginal. Also skaters can be a bit superstitious, have a crap session, blame the stoopid new fangled trucks.
Anyway may take on it, but not skated for years.
The killer feature of Independents was simply that they were the most durable. I suspect this was a big reason they became “classic”. Over time they spent longer on the average skater’s board than other brands (which got replaced when they broke). No idea if this was because of geometry, or manufacturing quality, or materials, etc.
I remember Tracker trucks tried a different pivot geometry. I gave up on them after the 2nd or 3rd one broke on me and I had to walk home.
But new trucks are a disaster you wouldn't wish on anyone.
No one wants traditional truck designs to change because that would be like new trucks x100.
This all relates to how difficult skateboarding is, and how your entire body's muscle memory is utterly reliant on a very specific set of reliable behaviours from your trucks.
'Improve' the trucks and the skater will get worse. So we're just not interested.
If you want to make better trucks, make some where the kingpins don’t break all the time. Every skateboarder will be buying your trucks within a year or two. You’ll be an overnight success guaranteed.
Titanium kingpins are available for skates and skateboards, and are much lighter. I don't know if they help with breakage.
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Yes, I'm on an old laptop, but it works with most sites. No way to even let the current browser try. It's just a blog post. Kind of a fail, if you ask me.
He had patented it at vast expense and was in discussions with a couple of big retailers, and manufacturers.
This was late 2000s. I wonder sometimes if anything came of it.
there are, in fact, TKP trucks on longboards, there are extensive discussions on r/longboarding about the differences, and what it boils down to is that a skateboard is an individualized piece of equipment, and it will work differently with every human being because of the geometry of their legs, feet, ankles, muscles, ligaments, shoes, the kind of riding they do, the type of pavement they ride in, the weather they ride in,whether they do vert skating or "transition" (ramps/bumps), rails, massive jumps, ground tricks, carving, downhill bombs, long distance push, pumping, etc etc, and even the way their mind works in relation to their body.
so the amorphous concept of "feel" is, basically, everything on a skateboard. the top end skateboarding engineers like Paul Schmitt ( https://www.youtube.com/watch?v=18MRZq0bhpE ) will spend endless hours interacting with skateboarders to get continuous feedback about anything from wheel chemistry to changes in board shape. There is another interview there with rider Andy Anderson where he talks about how they shaved part of the sides of his board down in a slight taper so that it would be balanced evenly due to one side being slightly differently shaped than the other. To a casual watching him at the Olympics, you could not even tell which side of this board was front and back let alone if the sides had gotten tapered. That was just one many things he had put into the design of his board, all tailored around the style he wanted to skate (which is a lot of older freestyle like Primo and pogo hops combined with all the newer olympics stuff ).
im sure there is some room to innovate trucks but it takes a lot of back and forth with a rider, its not , like the cat food can thing, a single variable optimization.
As a software developer, luckily I always find out very quickly why designs aren’t as bad as they might seem at first sight. You just delete the seemingly negligent design, substitute your own, and wait for the reports of the regressions. Then in a hurry substitute back the original design, with an additional comment.
Software development is easy.
> As I researched deeper without finding a satisfactory explanation, I was tempted to think that these were just glaring, negligent design errors. But I hesitated to come to such a strong conclusion.
A huge amount of noise in internet comments (especially HN) is driven by people who give in to that temptation, and jump to self-aggrandizing criticism.
> I love this tweet about a math professor who wrote a letter to Carnation, a canned cat food manufacturing company. He wrote to explain how they could optimize their can geometry for lower costs – it’s a classic calculus problem to find the optimal cylinder dimensions to minimize surface area-to-volume ratio. The company wrote back, but not to praise his insight. They kindly explained 5 other, obscure factors for the can’s design that he hadn't considered. Unlike calculus class, in the real world there are very few one-dimensional optimization problems.
IMHO, when you have an opinion, it's more fruitful to think about the factors you missed in your analysis.
I love that the author acknowledges Chesterton's Fence.
The feel is definitely different, but welcome on my geriatric knees. I learned about them from this video: https://youtu.be/8_ZaUQTU8k0
It’s not supposed to be easy. Even riding in shorts is sort of frowned upon. Most people don’t use helmets and riding an old banged up board with noisy bearings is way cooler than using a fresh new one.
forum.esk8.news
Have you ever gone 50mph up a hill on a skateboard with the feeling of total stability? If not, consider a price tag you may put on that experience if it were something you were into.
along with the wealth of knowledge & documentation of technique that comes with that. Just taking into account raw metal… no, it’s not that much money worth of metal. There are more than a few machining operations though, & those stack up a bit.
And then there are esoteric designs like double kingpin!
Two and four wheel vehicles are not all that different as far as steering stability. Both need caster and trail for stability and responsiveness. Yes the control input is different.
I'm not saying he's entirely wrong, just that I don't think he's read much on steering geometry, and if he did he might understand the problem better.
But that actually balances out fine. Is the claim that some of the work in compressing the bushing is never given back in energy restoring the truck to neutral?
Maybe it's not possible to manufacture a squishier bushing so the mechanical advantage/disadvantage is needed.
I believe they're stronger for the weight and less likely to fail catastrophically.