Swapping a rear tire with a different size can affect the performance, handling, and safety of your motorcycle. The tire size you mentioned, 130/80/18, has a different aspect ratio (80) and rim size (18) compared to the original tire size of 130/80/17 on the Bajaj NS 200.
Changing the aspect ratio and rim size can impact the overall geometry and dynamics of your motorcycle. It may alter the speedometer reading, affect the accuracy of the odometer, and potentially cause clearance issues with the swingarm, fenders, and other components.
Additionally, the tire's load rating, speed rating, and construction should be considered to ensure they meet the specifications required for your motorcycle. These ratings are typically indicated on the tire sidewall and may vary between different tire brands and models.
To ensure the best fit and performance, it's advisable to consult a trusted mechanic, refer to the manufacturer's recommendations, or reach out to Bajaj directly for guidance on tire substitutions for your NS 200.