Recommended Additional Upgrades
01
Uma Laser Iridium Spark Plug
Improve ignition with Uma Racing Laser Iridium Spark Plug.
03
Uma Racing Engine Oil
Get smoother engine performance with Uma Racing Full Synthetic Engine Oil.
The UMA Racing High Performance CVT Belt for the Yamaha Aerox 155 and NMAX 155 is a heavy-duty upgrade over the standard OEM rubber belt. In a CVT system, the belt is the “weakest link” under heat and high torque; UMA addresses this by using advanced materials that prevent the belt from stretching or snapping during high-speed runs.
It is designed to handle the increased load of tuned engines, especially those with high-tension torque springs (1000RPM/1500RPM).
Key Features
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Aramid/Kevlar Reinforcement: The belt is embedded with high-tensile fibers (often Aramid or Kevlar) that provide exceptional strength. This prevents the belt from stretching under high RPMs, ensuring your gear ratios remain consistent.
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Superior Heat Resistance: Standard belts can become “soft” or “mushy” when they get hot, leading to power loss. UMA belts are engineered to maintain their structural integrity and “grip” even in high-temperature racing environments.
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EPDM Rubber Compound: Uses high-grade Ethylene Propylene Diene Monomer (EPDM) rubber, which offers better resistance to cracking and weather aging compared to standard chloroprene rubber.
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High-Friction Cog Design: The “teeth” or cogs on the belt are precision-molded to provide maximum surface contact with the pulleys, reducing “slip” when you snap the throttle open.
Technical Specifications
| Feature | UMA Racing CVT Belt Details |
| Material | Aramid Fiber Reinforced EPDM Rubber |
| Compatibility | Yamaha Aerox 155 (V1/V2), NMAX 155 (V1/V2), NVX 155 |
| Durability | High-Resistance to Stretching & Snapping |
| Performance | Optimized for High-Torque / Racing |
Why Upgrade Your Belt?
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Modified Engines: If you have a 62mm/63mm big-bore kit, the stock belt will wear out significantly faster due to the extra torque. The UMA belt is built to handle that extra “punch.”
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Eliminate “Shudder”: A worn or stretched belt often causes a vibration or “shuddering” sensation during low-speed take-off. The stiffness of the UMA belt helps provide a smoother, more direct engagement.
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Longer Service Life: For long-distance touring, the UMA belt offers peace of mind, as it is far less likely to snap during a long, high-speed cruise on the highway.
Installation & Maintenance Tips
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Directional Arrow: Most performance belts are directional. Look for an arrow printed on the belt; it must point in the direction of the engine’s rotation (towards the front of the bike).
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The “Break-in” Period: Do not go full throttle immediately after installation. Give the belt about 50–100 km of moderate riding to “seat” itself into the pulley grooves.
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Check Your Pulleys: If your pulleys have deep grooves or “steps” worn into them, a new belt will wear out prematurely. Always inspect the faces of your primary and secondary pulleys during installation.
Pro-Tip: For the ultimate CVT setup, pair this belt with the UMA High Speed Pulley and the UMA 1000RPM Torque Spring. This combination ensures maximum power transfer to the rear wheel with zero slip.
FAQs
How do I know my CVT belt needs replacement?
Common signs include slower pickup, slipping, vibration, cracks, or reduced top speed.
Is this better than a worn stock belt?
Yes, a fresh premium belt usually restores smoother acceleration and efficiency.
Can I use this with pulley upgrades?
Yes, it is suitable for stock and tuned CVT setups.
