The Yamaha FZ-S version 2.0 typically comes equipped with a rear tire size of 140/60-17. If you were to use a slightly different tire size, such as a 140/70-17, there would be a few potential effects:
Increased tire height: The second number in the tire size represents the aspect ratio, which is the height of the tire sidewall as a percentage of the tire's width. In the case of the 140/70-17 tire, the sidewall height would be slightly greater compared to the stock 140/60-17 tire. This would result in a slightly taller rear tire, which could affect the bike's handling characteristics and overall geometry.
Altered speedometer accuracy: With a larger tire diameter, the speedometer reading may become slightly inaccurate. Since the speedometer is calibrated based on the stock tire size, using a larger rear tire may cause the speedometer to display a lower speed than your actual velocity.
Handling changes: The use of a different tire size can impact the handling of the motorcycle. A taller tire may affect the bike's agility and maneuverability. It could potentially result in slower turn-in response and a slight decrease in overall handling performance. Additionally, the altered geometry caused by a taller rear tire may affect the bike's stability at higher speeds.
Suspension adjustment: Changing the tire size can also impact the suspension behavior. The altered tire height may require adjustments to the suspension settings to maintain the desired ride quality and handling characteristics.
It's important to note that using a tire size that deviates significantly from the manufacturer's recommendations can have unintended consequences and may compromise the safety and performance of your motorcycle. It's generally recommended to stick to the tire sizes specified by the manufacturer or consult with a qualified mechanic or motorcycle specialist to ensure compatibility and proper fitment.