I really appreciate the technical write up of how trucks work. As others have pointed out, skateboarding is all about feel, and not efficiency. My favorite example of this is Daewon Song, one of the most skilled and creative skaters of all time. Somehow he rides a board with no top bushing on his front truck! [1] Even most skilled skaters would have a hard time rolling down the sidewalk on this, let alone tricking it in any way.
Wow that’s amazing a.f., never knew he removed any bushings. He says it’s “fairly loose” and that thing is just flopping around!
Like some of his newish stuff around removing/replacing wheels during tricks which seems similar to this in a way.
Thanks for the vid.
one of my favourites, he has always had such a casual style, looking almost unrefined but his board control is sublime.
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.
Roller skating plate trucks are similar to skateboard trucks.
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.
In skateboarding people tend to use angled riser pads to adjust the kingpin angle. As a side effect these riser pads can (ever so slightly) absorb hard shocks and decrease the chance of a wheel-bite (when your wheel comes into contact with the wood of the deck and stops you apruptly). This is not necessary with most longboards as they usually have a higher clearance, or even cutouts at the sports where wheelbites would occur. In street skateboarding the tradeoff is a little different, because the area where wheelbites occur are just next to the area "the pocket" you utilize for nearly all flip tricks. Also taking wood away there would have a negative impact on stability so street skaters would rather live with wheel bites than sacrificing wood area there – or as mentioned use the stiffest pushing you can find, use riser pad, tighten the trucks or similar.
As a previous skateboarder, the sweet spot is having full weight on a corner and having about 5mm of space between the wheel and the board. Wheel diameter also plays into the equation. Smaller wheels are used for looser KPT truck setups to reduce the wheel bite mark while increasing the truck turning capability. Risers further this difference. A standard park/street setup is different than, say, a downhill setup or what you find at your local department store. 48-52mm wheels instead of 56-58mm.
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.
About Zero people use riser pads in modern skateboarding. Nobody cares about wheel-biting either, even with loose trucks. if you wheel-bite and fall, you failed to land your trick. The goal is to land 'bolts', as kids say. (Source - any skate video)
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.
Yeah, this guy doesn't (as he admits) understand a skaters mindset or culture.
If you ride Indy's you're buying into classic solid trucks, and if you been skating a long time you are likely to be nostalgic.
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.
I skated all sorts of different stuff in the late 20th Century, including different trucks.
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.
There is probably some nostalgic influence, but it doesn't seem like that is the reason. There are many different truck companies that exist and try to tweak the design to improve some aspects. Some of these companies will be trendy for a while and have pro riders, etc. but most people stick with the Indy/Thunder/Venture trucks, which are almost the exact same design. I think the later part of the article is more accurate, it is a combination of turning, impact and grinding. It is not a coincidence that almost all street/vert skateboards have converged to the exact same shape & dimensions. It's some kind of unconscious 'survival of the fittest shape' thing going on now for many year.
You can replace the wheels, bearings and even deck on a skateboard with fairly manageable consequences.
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.
This article doesn’t even discuss the eternal problem of broken kingpins. Skateboarders don’t care about “turning efficiency”. I don’t even understand what that is.
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.
Having broken a couple of kingpins at high speed on roller skates, it's definitely no fun. Unfortunately, the kingpins are under a lot of stress and they're threaded. Invariably, the break occurs on the threads.
Titanium kingpins are available for skates and skateboards, and are much lighter. I don't know if they help with breakage.
When a kingpin breaks it's almost always complete mechanical failure, e.g. it snaps in half one way or another. In addition, it's usually not possible to foresee it happening by visual inspection, the wear and tear is internal.
I think the problem is using better quality materials doesn't really show up or become apparent unless you are already breaking kingpins all the time. It would take a significant marketing budget to convince people to spend 50% more on your trucks for small gains in material strength/quality, and that marketing will quickly wipe out the advantage of potentially higher sales. Will people see it as worth it when the majority of people aren't breaking them often enough in the first place to be concerned with it?
> To view this website and enjoy a better online experience,
update your browser for free.
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.
I met a guy in a pub once who had invented a new type of truck. I'm not a skater so I didn't totally understand the significance, but somehow it could flip 180 degrees while being ridden. Apparently this opened up new kinds of tricks.
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.
Oh, interesting. I don't think it was that though. My understanding was that somehow the entire truck ended up flipping around 180 degrees (or more). And I didn't quite understand why that was a good thing - I think it was mostly about letting you do new kinds of tricks that weren't otherwise possible.
That guy obviously wasn’t a skateboarder. Inventing new tricks with new technology is considered by skateboarders to be inventing another sport altogether.
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.
Interesting article. There is no mentioning of the art of Slalom Skateboarding, one of the absolute oldest styles of skateboarding. In this style the truck design is absolute critical. Still use the same basic design, but with adjustable angles and very short hangers. Also we keep a bag of different bushings to tune the board to different track setups. Check out G.O.G. trucks, the absolute undesputed best trucks for slalom skateboarding. Also Don't Trip makes good trucks for this style
The answer is that turn precision just isn’t important to street skaters. Many ride their trucks absurdly tight anyway. They aren’t turning by leaning very often. Other capabilities are far more important: durability, cost, grindability, etc.
> I was tempted to think that these were just glaring, negligent design errors.
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.
> 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 suspected my question was similar - I noticed these two glaring flaws, but there are likely other, less obvious factors that contribute to the TKP design. So here are my speculations.
I love that the author acknowledges Chesterton's Fence.
I haven’t seen mention here of suspension trucks
https://avenuetrucks.com/
These replace the pivot with a very stiff spring, while still having a (floating) king-ish pin and grommets. The spring means there’s no single pivot axis, so I’m not sure how to apply the author’s analysis; does anyone else know?
The feel is definitely different, but welcome on my geriatric knees. I learned about them from this video:
https://youtu.be/8_ZaUQTU8k0
I don’t think there is any athletic endeavor where people care less about “optimizing performance” than in skateboarding, especially in street. Partly because there is no sport or game where the equipment matters less (not even beginners think that getting another board will perceptibly improve there riding), but also because it’s almost a point of pride to be able to ride in suboptimal conditions.
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.
You can make your own if you have access to some basic machines, otherwise, they’re more than worth it.
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.
To my knowledge, you’re paying for the 4+ years of constant extreme testing & revision of the design by some of the fastest skaters in the world (seriously, have been ridden by dude who held #2 downhill world record as of 2018)
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.
In a scenario like this, it’s almost always a mistake to assume that the things you are measuring map directly to what the users “feel”. Sure, there may be some superstition involved, but however the skaters describe what they like or dislike about certain designs, you shouldn’t assume the measurement you are making maps to that property.
Independent makes really wide TKP trucks, so you can feel the difference by putting them on the same deck and wheels as similarly sized RKP. They feel very different. On TKP the first part of the turn is really fast, and then it becomes harder to make the rest of the turn. This is really good for breaking out into stand up slides, but scary if you're going fast. When I was mucking with them, a buddy who is a much better rider than me but hadn't tried wide TKPs was amazed at how much easier it was to do heelside slides, but we both agreed -- way too scary at speed. For park tricks though, that super fast first pump is a feature. I don't buy that it's about weight or grinding, I'm sure it's the turn.
And then there are esoteric designs like double kingpin!
Here is an example of the racing that the cutting edge or RKP trucks are optimised for. Extremely narrow slalom trucks for high speed racing is a relatively recent development.
He should read up on steering geometry in general. The wheel axis always needs to be offset from the pivot axis or the steering will be unstable. Take a look at your bicycle and you'll see that the axle of the front wheel is at an offset from the steering axis, because the fork is curved (or offset).
Is it possible you are using wrong terms here, or perhaps don't completely understand what this is about? For starters boards have 4 wheels, completely different from the 2 wheel countersteering business, and the axis is offset from the pivot point in all truck designs?
I am using non-standard terms, because that's what he's using. The angle between the steering axis (what he calls the pivot axis) and the vertical is usually called caster angle, and the offset between the steering axis and the wheel axle is usually called trail. He doesn't talk about trail directly, but he suggests that the pivot axis and hanger axis being different is a problem. If they were the same, there would be no trail, and that would be a problem.
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.
Not sure about dividing the force compressing the bushings into Fuseful and Fwasted. I may be misunderstanding, but it seems the Fwasted vector component just gets some mechanical advantage in compressing the bushing, and disadvantage on the restoring force.
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?
No energy is lost. Imagine a spring installed at an angle between 2 plates being pressed together (the middle bit of a 'Z'). The spring has to be stronger/beefier than a spring installed vertically (middle bit of an 'I'). It may wear out faster.
Maybe it's not possible to manufacture a squishier bushing so the mechanical advantage/disadvantage is needed.
Hmm I was curious about the durability part when comparing the trucks. As an ex-skateboarder (lies I still ride around for fun but tricks are hard on my older body) I can say my trucks typically “grinded” away in the middle from, well, grinding. The only breaks haven’t been around the kingpin but more on the sides of the “T” near the wheels.
[1] https://www.youtube.com/watch?v=pt--3DX-md0