The Qualities Of Urethane

What makes a good wheel?

They’ve all got their secrets–formulations, processes, and preferences. Manufacturers, designers, and the skaters who test and ride them are all integral players in the development of new wheels, and each have their own way of doing what they do. What we’re accustomed to seeing, though, is the seemingly simple end product–the polyurethane doughnuts that we’ve been rolling on for years. How deceptive they are.

Since skateboarders adopted polyurethane as the wheel material of choice in 1973, over a quarter century of R&D has refined the chemistry and manufacturing processes to produce the most resilient and dynamic wheels skateboarders have ever ridden. Many manufacturers have been making wheels just as long, so it should come as no surprise that they’re pretty tight-lipped about the tricks of their trade.

That didn’t stop us from prying, though. We called on some of skateboarding’s premier wheel designers, testers, and manufacturers to find out what they thought made a good wheel. Of course, all the technical jargon didn’t make much sense, so we wouldn’t have known a trade secret if one hit us in the face. But a lot of what they had to say didmake sense, and suggested what properties they’re working to improve, and what might be in store for the next generation of skateboard wheels.

Tim Piumarta–Santa Cruz/Bullet Director Of R&D

“What really makes a great wheel are the ingredients and the chemist who literally puts in his time to work with skaters to come up with the best formulas. But to break it down to characteristics, it would be rebound first, then weight. As you know, with Bullet Holes and things like that I’ve been really interested in reducing weight on wheels–weight and mass–and yet keeping the speed of a large wheel with the size and mass of a small wheel.

“Shape has some to do with it, and I think there are people doing groundbreaking work out there who are going to be teaching us in the next couple years about shape, speed, and performance. I know that I try to do my shapes with minimal mass, which probably goes along with this new theory. Having a bloated radius out on the edge of the wheel just because it’s a great place to print is not functional.

“I used to dislike pigment in wheels. But you know what? People need more variety than just white. White gets really bland really fast. If people didn’t want variety, we’d all be riding blank boards, but graphics are cosmetic, and colors are cosmetic. So you can’t just live off white alone. God, if we were all just sitting in a sea of white wheels on a shelf, it would be boring walking in the store.

“A great wheel is a great formula, a formula that makes the riders happy. You can make formulas to be cheap, cost-effective, and to reach pricepoints and all that, but really–ultimately–if you can satisfy the needs of your skate team, then you’ve done it–you’ve made a great wheel. They are the most demanding people on the planet when it comes to wheels.”

Mike Vallely–Accel. Urethane Brand Manager And Team Pro

“A wheel that doesn’t die immediately is a good wheel. I’ve skated many wheels that have very short life span. Most wheels feel pretty decent the first day you put them on, then they just progressively get worse and worse. And that’s gonna happen with any wheel, but a wheel that lasts a little bit longer than the others makes the difference for me. It always has.

“I don’t like to waste product, and I don’t like to change wheels all the time. The wheels I’m skating right now are about a month-and-a-half old, and I’m very happy with that. I don’t have to worry about changing my wheels every other day, which I see a lot of professionals do–obviously because they can. But when I think about customers out there who actually have to buy wheels, I think it’s good if there’s a company or companies supplying them with something that’s gonna last a little bit.

“If it’s a good set of wheels, you sort of adapt with them as they change size, and it’s a rather comfortable transition. If they’re bad wheels, the change is drastic, it’s painful, and you have to take them off.

“There’re people at these urethane companies who come up with these formulas, mix these chemicals, and try to make wheels better. I definitely have a greater respect for them, and realize their importance. It’s not just about kids on the street or pros skating wheels, it’s a lot deeper.”

Darryl Readshaw–Elasco Urethane Products Chief Operating Officer

“Surprisingly enough, many of the new formulas we have right now are kind of variations on themes we did in the mid 70s and 80s. If you go back to 1996, really only two basic formulas were used in this industry. If you go back ten years there were probably ten, then it merged down to two. Now it’s kind of back up. We’re running five to seven different ones.

“The market’s becoming a lot more diversified–they want a lot of different things. Two years ago, it was just a different print on a wheel. That’s not the case now.

“As wheels wear, their dynamics change. They fray a little bit, they become a little slower, and they may not perform the same on blacktop as they do on concrete. So the whole idea here is that the longer you can keep that wheel from changing, the better off the skater’s gonna be to really improve their ownabilities.

“Shape’s a funny thing. Some customers like wider wheels, some customers like thinner wheels. Obviously, if you had a 58-millimeter wheel, and it was one-inch thick versus two-inches thick, the two-inch-thick one theoretically should be a lot slower. But on the other hand, the two-inch one will give you a lot more stability, and the one-inch one will give you a lot more maneuverability. So that’s really an individual preference; it’s more subjective than the formula side of it.”

Josh Beagle–Pig Wheels Creative Director

“A good wheel is one that doesn’t flat-spot or chip, and depending on what terrain you’re riding, one that actually slides when you try a lipslide on a ledge–it’s not gonna stick if it says 101. We basically try to make each wheel go with the terrain.

“I always ask the team what they like in a wheel: ‘Do you like fatter shapes? Thinner shapes? What do you think about clear wheels? What do you think about this? What do you think about that?’ We work with the manufacturer closely, then I’ll send samples to the team, and they’ll get back to me on different shapes and cuts and whatnot. If they like it a lot, then we’ll go with it.

“Some people think all wheels are the same, and they’re not. The wheel companies manufacturers are always doing research and sending us samples of their newest stuff. Either we ask for it, or they come up with something new.

“We have the big soft wheels, a basic shape, a skinnier shape, and we’re gonna do an in-between one that’s more rounded. When we first started Pig four years ago we made up our own shape that kind of went around and dipped in. But right now we basically have three shapes, and durometers in 82, 95, 99, and 101.

“We’ve been testing dual durometers for a while. We went through a couple different people to do them, and we finally found someone who does it right. We tested them out, and they’re awesome. We’re working on more shapes now, too.”

George Powell–Powell/Bones Owner

“Everybody wants to go fast, so I always try to maximize rebound. Then I try to maximize abrasion resistance, cut-and-tear resistance, and minimize compression. And I have to adjust my formulas and materials to get the best compromise of all those things.

“I’ve learned some interesting things along the way since the first Bones urethane back in the 70s. Urethanes are basically divided into two families of isocyanates. You have to understand the chemistry of urethane wheels in order to kind of understand where people like me go and what we do to get a better whe
el. I think I said once a long time ago, ‘You can’t build high-performance products without high-performance materials.’ That’s been more or less true.

“If decks were made out of carbon-fiber, epoxy, urethane, and stuff like that, then it deck production would be more like wheel development. Wheels have always been more technical. Some of the formulations that prove to give the best properties tend to be difficult to pour; you get into all kinds of variables that are interesting.

“Shapes are simple–we try different stuff, and the team defines the shapes. Our the company’s job is to come up with the materials and figure out how to process them consistently. That’s kind of what goes on behind the scenes, as you’d expect.”

Rodney Mullen–Dwindle Distribution Team Manager And A-Team Pro

“I look at dimensions first. I ride 50s, and I tend to go toward as narrow a wheel as possible without getting flat spots. I’m really strict on width–I hate it when they have that heavy feel.

“A lot of people make them a little softer to avoid flat-spotting, but if they’re that narrow, then you run the risk of them having a sort of mushy feel. Sometimes people make them extra hard, but when they do that, the wheels feel really dead or rocky at best. When they’re wider, they’re just heavy, they’re slow to get moving, and they tend to wheel bite because they stick out more.

“So they can’t be rocky dead, and they definitely can’t mush out from under you, and that’s where dual durometers come in, because they can allow a little bit softer tire with a harder inner core.

“I prefer wheels that are not too square on the edge, really round. It started with the Jason Lee wheels of way back–sort of yo-yo width. That’s the present look of wheels–as minimalistic as possible. The dual durometers are, to me, by far the best thing that’s been done. Urethane to urethane–that stuff makes a huge difference.”

John Tiedemann–Creative Urethane Vice President

“Creative was making wheels back in the early 70s, so we’ve kind of carried forward this formulation that’s been through a lot of testing. In the 80s we did Speed Wheels exclusively, and we’ve kept that basic chemistry; it has changed somewhat, but basically we’ve kept that same idea.

“I’m a chemist by background, and we’ve made some improvements in hardness and things like that, but I think what makes a really good wheel is consistency. We’ve spent a great deal of money and effort to bring our manufacturing equipment to a point where it always makes the same thing every time. That, coupled with some pretty tough QC quality-control standards makes a very consistent wheel. I think that’s something our customers can depend on.

“I guess when something ain’t broke, you don’t fix it. I mean, I’m still looking, but I’m looking at real high-tech materials that are coming onto the marketplace. The problem with that seems to be economics. Most of the new materials are like twice the price per pound as the stuff we’re already using. That gets difficult to sell unless it’s really significantly better. So we’re always looking, and we’ll probably keep on putting stuff out there for tests like we always have, but it seems like we end up coming back to the tried-and-true stuff.”

Jason Phares–Spitfire Team Manager

“It’s all about having everything out there for everybody–good urethane, good shapes, a variety of hardnesses. Some people like skinny wheels, some people like wide wheels. I personally like Spitfires for the way they break away when you slide on hills–it’ll let you slide, but it’s not gonna hold on and burn a flat spot that easily. The normal one’s a 99, and we have a 97 that’s just a little bit grippier, but it still breaks away just fine.

“We run two pro-model wheels at a time. I give them the pros pretty much all control on it–whatever they want. Kris Markovich right now likes 50, and a little skinnier than our Classic 50. So we made his a little skinnier.

“Just recently everybody on the team said they wanted more skinny wheels in a 55 range. Then there’s guys who say they want real wide wheels, so we make sure we have the wide ones out there, too.

“The Power Cored insert doesn’t make the wheel feel different. It’s good to have a hard surface where your bearing sits so the bearing doesn’t squish out. Our cores are like normal urethane, 99A, then the outer material varies from 92 to 97. So the bearing just sits like it normally would in a regular hard wheel.”

Tim Dawe–Electric Urethane (Cortech, Electro) Owner

“We engineer our application to our material. I’ll take a urethane blend, and I’ll build a shape to it. If the chemistry and the geometry are put together properly, the wheel will work better. If you’ve got a wheel, and the material is not that good at wearing–in other words the abrasion resistance might not be that good–you’re not gonna be able to go as narrow in the riding surface, ’cause you’re gonna flat-spot the wheel.

“Because of our materials, we can go really narrow. They’re skinny in the riding surface, and they don’t flat-spot. This is because of the abrasion resistance and the rebound resiliency in our blends.

“If a wheel’s got less abrasion resistance, it’s gonna break out sooner than another wheel–it’s gonna slide more. But the problem is, if it breaks out sooner and slides too much, it’s gonna flat-spot. As soon as it lets go over a bump, it abrades the material across the bump. When the material’s high-rebound and very resilient, it holds on more–it doesn’t bounce across those bumps–and literally pushes the wheel forward. Whereas, if you’ve got a dead material, it’s gonna literally pick itself up and slide the hell across the tops of all those little mountains.

“If that wheel has the right amount of rebound and resiliency, when it hits the ground the wheel compresses, and when it moves forward it unweights and pushes the wheel forward. What happens with anything that’s rock hard is that they don’t have enough life in them, and they’re slow because they’re literally bouncing–particularly on rough surfaces.

“Everything is interlocked, and you really have to know your formulas. But the problem we have here is that the people who are telling the industrialists what they want can’t make wheels, and the industrialists can’t skate and can’t relate to what those other people are trying to tell them. So there’s missing information there.

“You can start talking about the radiuses of the wheel, for instance. If you’ve got a wheel with a narrow riding surface and a very rounded radius, depending on the material itself, the wheel will bulge out under those radiuses, give a wider riding surface, and slow the wheel down. On our wheels the radiuses are very steep. As the wheel does wear down, it won’t slow down so much because the riding surface is still not widening. Because of our material, it’s supporting the wheel more.

“In 1992 we developed the dual-durometer core wheel. When you put that core system in the wheel, everything changes. Those factors I just spoke about are still in play, but a whole new set of factors comes in. Elongation is one of the factors–it’s the way the material bends. Another factor is the way the material returns. So you’ve got the bloody abrasion resistance, elongation, and resiliency all acting together to hold that wheel onto the surface–to stop it from getting a flat spot. You’ve got all these characteristics of urethane materials, but if you talked about them you’d confuse the hell out of everyone.”