Review on Superior Quality Jumbo Zirconia: Unrivaled Premium High Density by Justin Puranik

These discs are great for descaling, especially for the price you pay. When used brand new they come out of the gate with incredible power, but that only lasts for the first minute. They wear out quickly initially, from zero descaling effort to little descaling patience, but they maintain that "medium life" wear point for a significant period of time. I would say you get the average performance of this wheel for another 10 minutes of constant descaling until you start to hit a lower level of descaling speed. As a last resort, I'd say you can run this bike for 30 minutes (continuously) before you lose interest in the same thing. Again, for the price you're paying, you can toss those used Zirc wheels aside pretty quickly lest you go broke. Unless you're in a heavy commercial environment, this is my go-to choice for all day use.