Will Upgrading From B78-13 Tire to ST205/75R14 Be Okay for a Zieman J-2B Watercraft Trailer  

I have a Zieman J-2B which is a double watercraft trailer with storage box mounted in the front. The original stock wheel and tire size was B78-13ST and the bearing buddy axle has a 5 lug x 4” or 4-1/2” diameter bolt pattern. As I understand it, the original tire size is now obsolete and has been superseded by special purpose Bias type trailer tires size: 175/80- R13. My question is in regards to the pros and cons as well as the fit and functionality for changing the wheel and tire size from the original 175/80-R13 size to 205/75-R14. I understand that this would increase the overall dimensions by approximately 2” in total diameter and 1” in the total width. I also understand that these tires are an upgrade option on similar trailers manufactured by Zieman as well. Provided that I am able to maintain adequate clearance inside the wheel wells / fenders, will this change to the wheel and tire size work? Have I missed anything or are there any other important factors that I need to consider? Other than the 1” increase in ground clearance, what other characteristics do larger tire sizes exhibit on trailers? Will the increased ground contact surface area help with load support and control at the expense of a small decrease in fuel efficiency? I just want to ensure that I understand the characteristics of tire performance on trailers and how the size and type of tire effects those performance characteristics. Thank you for your assistance. I appreciate your time and consideration.

asked by: Chris