While it is technically possible to use a 150/70 R17 winter tire instead of the regular 150/60 R17 road tire on your KTM Duke 390, there are a few factors to consider before making such a substitution.
Fitment: The 150/70 R17 winter tire has a larger sidewall height compared to the 150/60 R17 road tire. This can potentially affect the fitment of the tire within the motorcycle's frame and fender clearance. It's essential to ensure that the larger tire will not interfere with any components of the bike or cause any clearance issues, especially during suspension travel.
Handling and Performance: The larger sidewall of the 150/70 R17 tire can impact the bike's handling characteristics. It may alter the bike's steering response, cornering ability, and overall stability. Winter tires are designed with specific tread patterns and compounds for cold weather conditions, emphasizing traction on snow and ice. Using them on regular road surfaces may result in reduced grip and handling performance compared to dedicated road tires.
Speedometer Accuracy: Swapping to a tire with a different aspect ratio, such as the 150/70 R17 winter tire, can affect the accuracy of your motorcycle's speedometer and odometer readings. The change in overall tire diameter will result in a variance in the rotational speed, potentially leading to incorrect speed and distance measurements.
Regulatory Considerations: It's important to verify if using a different tire size complies with local regulations and safety standards. Some jurisdictions may have specific requirements regarding tire sizes and types, and deviating from these regulations may lead to legal complications or insurance issues.
Considering these factors, it is generally recommended to stick with the manufacturer-recommended tire sizes for your motorcycle. These specifications are determined based on factors like handling, performance, and safety. If you have specific requirements or preferences for winter riding, it's advisable to consult with a knowledgeable motorcycle tire specialist or your KTM dealership to find suitable options that are compatible with your bike and meet your needs.