[Graeme Smith]

I spoke with the Optibelt suppliers here in Australia and they checked out the current belt Robin supplied against the #vXK1120 & 1180 and they said both belts are not approved to run twisted (our system twists the belts 30 degrees between each set of pullies. So I then asked Google what is the best belt that would handle the twist and the power etc, this is the responce.......

Based on the need for a 3VX-section cogged belt (approx. 1180mm effective length) capable of handling a 30-degree twist, the best alternatives to the Optibelt 3VX1180 XEP (Super XE-POWER PRO) are those that emphasize high flexibility, EPDM rubber construction, and raw-edge design to reduce bending stress and manage misalignment. 
The best alternatives for high-twist, raw-edge applications include:
Top Alternatives to Optibelt 3VX1180 XEP

1. Gates Quad-Power 4 (XPZ/3VX):
   • Why: This is a premium EPDM rubber, raw-edge, cogged, maintenance-free belt that rivals the Optibelt XEP. It is designed for high efficiency and flexibility, allowing it to handle twisting and back-side idlers better than standard wrapped belts.
     
2. BESTORQ 3VX1180 Raw Edge/Cogged:
   • Why: These are highly engineered for flexibility, with manufacturers claiming they require 40% less energy to bend around pulleys compared to standard belts. This flexibility is ideal for handling 30-degree twists without excessive heat buildup.
     
3. Optibelt SUPER X-POWER M=S (3VX1180):
   • Why: If staying with Optibelt, the slightly lower-tier (but still very high performance) Super X-Power is an excellent, flexible, raw-edge cogged option.
     
4. PIX-X'set (3VX1180):
   • Why: A high-performance molded cogged belt with good flexibility and power capacity, often used as a direct, high-quality replacement for 3VX raw-edge belts. 
     

Key Considerations for 30-Degree Twists

• Raw-Edge Cogged Design: Only use "raw edge cogged" (molded cogged) belts. These have no fabric covering on the sides, which allows for much greater flexibility and reduced stress when subjected to a 30-degree twist.
  
• Material: EPDM rubber is preferred as it better handles the heat generated by the increased stress of a twisted drive compared to traditional neoprene.
  
• Banded vs. Single: Ensure you are using a single belt (or a, accurately matched set) for high-twist applications; banded belts (multiple belts joined together) are not designed for twists. 
  

Conclusion: The Gates Quad-Power 4 (3VX1180/XPZ1180) is likely the best direct alternative for maximum flexibility in a 30-degree twist scenario.