Seismic and 3dm wheels are poured at the world’s leading wheel factory, using the world’s finest urethane. But chunks and tears are an ever-present risk as wheels roll, turn, and slide on imperfect surfaces. Sharp projections, including small ones on fairly smooth roads, can catch and rip into even the best urethane wheels – in the same way that nails and glass can puncture even the best automobile tires.
(Seismic conducts regular lab tests in which wheels are subjected to extreme stresses as they roll on a smooth drum that simulates a perfectly uniform road. Our wheels never tear or chunk under these lab conditions.)
A tear that runs along a significant portion of a wheel’s circumference is clear evidence that the damage occurred when 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 elements. Softer wheels, and wheels with sharp edges, are more vulnerable to damage – especially under heavier, faster, and/or more aggressive riders. High-rebound compounds (such as Seismic’s Defcon™ formula) are also somewhat more vulnerable to chunking, but experienced racers agree that the added speed is worth it.
A very common cause of tears and chunks is sliding on rough surfaces – especially sliding off the road onto gravel, rocks, and dirt. Another common cause of chunking is kick-turning on rough surfaces, which can shred the edges of thin-lipped wheels (designed primarily for carving and cruising) in the course of a single skate session.
Soft urethane can even totally absorb sharp road residue – such as 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 “Alien” film series!)
On very rare occasions, an air bubble trapped in the lip of a wheel can break open under normal riding stresses on good surfaces. In these rare cases, the remnants of the bubble are fairly easy to see. But the surface is certainly 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.
As a general rule, Seismic does not warranty wheel damage caused by jagged surface anomalies, in the same way that auto tire manufacturers do not warranty damage caused by sharp objects on the road.