Can Trailer Tires be Downsized from 5.70-8 to 4.80-8 on a Fishing Boat Trailer

Question:

Can I replace 5.70 x 8 tires on my fishing boat trailer to 4.80 x 8 on those same rims? Thanks.

asked by: Rich D

Expert Reply:

Both the 4.80/4.00-8 Trailer Tire, like # AM10002 that you selected, and the 5.70-8 Trailer Tire, like # AM10010, are designed to fit on 8 x 3-3/4 inch rims, so the smaller tires will mount on your rims.

The problems come with weight capacity. The 4.80-8 trailer tires are only available in load range B and C while your original size tire is available in load range B, C and D. You will need to make sure that the tire you select is capable of carrying the gross weight of your trailer loaded and ready to travel.

4.80-8 Tire weight ratings are listed below along with the part number that corresponds to that load range.

B = Max Load 590 lbs at 60 psi, # AM10002
C = Max Load 760 lbs at 90 psi, # AM10004

5.70-8 Tire weight ratings are listed below along with the part number that corresponds to that load range.

B = Max Load 715 lbs at 50 psi, # AM10010
C = Max Load 910 lbs at 75 psi, # AM10012
D = Max Load 1,075 lbs at 100 psi, # AM10013

You can see that your options are extremely limited when downsizing trailer tires. I personally do not recommend downsizing. If there is a particular reason why you are thinking about downsizing, let me know why, and the loaded weight of your trailer, and I will be glad to try to make the best recommendation possible for your application.