Seismic and 3dm wheels are poured at the world’s leading wheel factory, using the world’s finest urethane. We’ve conducted extensive lab tests that subject wheels to extreme stresses as they roll on a smooth drum simulating a uniform road. Our wheels never tear or chunk under these lab conditions.
But chunks and tears are an ever-present risk as flexible urethane wheels roll, turn, slide, and impact on imperfect surfaces in the real world.
Even the best auto and bike tires can go flat if they roll over nails or glass. Likewise, even the best skateboard wheels can tear on nails, glass, gravel, pebbles, and small sharp residue on roads that otherwise seem smooth. In both cases, the damage is almost always a matter of physics and bad luck, not product defect. Probably only wheels made of steel would be 100% resistant to tears and chunks!
Seismic follows the basic protocol of the auto and bike industries. We evaluate each report on its own merit, and we occasionally replace torn wheels on a courtesy basis. But we don’t otherwise warranty wheels damaged by sharp surface elements without very clear evidence of product defect.
The most common causes of tearing and chunking include:
– sliding and hard cornering at higher speeds on rough surfaces
– drifting onto road shoulders and rolling / sliding over gravel, rocks, glass, and dirt
– rolling over sharp breaks in the riding surface, such as sidewalk edges – especially when most of the wheel loses contact and the lip bears all the load as it rolls over the sharp edge
– kick-turning on rough surfaces, which can shred the edges of longboard wheels in a single afternoon
– hard impacts – such as rolling over big bumps or cracks without unweighting; losing control and shooting the board into a curb; landing a board flip on the wheel edges; and missing a high board toss
A tear that runs along a significant portion of a wheel’s circumference (see photos above) is clear evidence that damage occurred as the wheel rolled or slid over a sharp surface element.
Harder wheels, and wheels with rounded edges, don’t catch as easily on jagged surface features. Softer wheels, and wheels with sharper edges, are more vulnerable to damage – especially in extreme heat; or under heavier, faster, more aggressive riders.
Soft urethane can even totally absorb bits of glass, jagged pebbles, and beer-can tabs. These objects can then work their way deep into a wheel and later split it open from the inside. (Think of the “Aliens” films!)
High-rebound race formulas – like Seismic Defcon™ – are somewhat more vulnerable to tearing. Their faster rate of energy return is only possible because they have an inherently “looser” molecular structure. But experienced racers generally agree that the added speed is worth it. Before doing any slides, we recommend breaking in all Defcon race wheels by riding them on a very smooth surface for 5 or 10 minutes – until the glossy outermost “skin” is gone.
Very tall, narrow race wheels (like the Seismic 85mm Speed Vent) may be more vulnerable to tearing and chunking, for at least two reasons: 1) The longer “lever arm” between the axle and lips amplifies forces acting on the edges; and 2) Those forces are not distributed across a wide contact patch.
On very rare occasions, an air bubble trapped in a wheel lip can break open under normal riding stresses on good surfaces. Remnants of burst bubbles are fairly easy to see, and we replace such wheels. But the riding surface is definitely the culprit if more than one wheel in a set of four has torn or chunked. (It is incredibly unlikely that one set would include multiple wheels with large air bubbles on the lip.)
I got these wheels in the Cristal Clear Blue 77 durometer for the rough, old chip & seal streets around my neighborhood. These things are just what the dr ordered. Smooth and fast.