Switching to Larger Tires on Boat Trailer With 4.80/4.00-8 Tires

Updated 12/15/2025 | Published 12/13/2025

Question:

I have a small boat trailer with 4.80-8 tires. I tried to put a 5.30-12 on but tread was tight to the tire-well fender. Would 480-12 or some other size work that would get me in a bigger diameter tire size? 480-12 is 1.4inch less in diameter that the 5.30-12 and would fit, but feat the 1.4inch is not enough gap between the fender and tire. The axle has a spring/shock.

asked by: Jim K

Expert Reply:

Hi Jim; a tire like the Kenda 4.80-12 Bias Trailer Tire # AM30630 you were looking at is only 0.2" wider than your typical 4.80/4.00-8 tire so that should still be enough inside clearance. The recommended clearance on top is 3" so at 1.4" you aren't going to have enough for that suspension travel.

I recommend either sticking with the original tire size or you can remove the fenders and either leave them off or add new ones to make sure you have enough clearance on top. What is your end goal with the larger tires?

expert reply by: Robin H

Kenda 4.80-12
(click to enlarge)

Matt I.

12/15/2025

Hi Jim, I upsized from smaller wheels and tires to 4.80 x12 for the same reasons. I took the fenders off of my "remodelled" Harbor Freight trailer and the wheels fit perfectly, added ground clearance, increased the load and speed range, and in my case moved me from painted wheels to the much more durable galvanized treatment. I have been very happy with the durability of the wheels and the quality of the Kenda tires, routinely towing 1200+ pounds on them at 65-70 mph. Matt