I switched from the 031 Cat belt to the Ultimax 3. The belt deflection was good with the ultimax, but it squealed excessivley. I shimmed the 2ndary which stopped the squealing and the belt deflection was still good, but the sled seemed like a dog and I could only achieve 7500 peak rpm. Unshimmed the secondary, threw on the old 031 belt, and voila, instant improvement. Peak rpm 7900. In my opinion the Ultimax 3 is closer to the 020 belt than the 031. For the price difference and the hassle I think from now on the extra 50 bux is worth it.