Re: do i need bigger tires?
As long as the weight of the boat, gear, motor, and trailer are under the max load capacity for the tire, they should be fine. By the looks of it, your boat/motor isn't that heavy given the fact it's an aluminum boat. One advantage to having larger tires though is bearing life, due to the fact that smaller tires have to turn faster to keep the same speed as the tow vehicle. Those look like 8" rims. IMO you should be fine with them.
