Special Trailer Tires to Replace 155R12 Radials on Boat Trailer

Updated 06/22/2016 | Published 06/21/2016

Question:

I have good year radials 155r12 T-metric on my boat trailer I like them because they ride smoother than bias tires. The original tires lasted about 4years and road hard the radial car tires i replaced them with are 23 years old and have never had a flat and run smooth. what is the equivalent today?

asked by: Stan

Expert Reply:

Radial type special trailer tires will tend to run smoother (and cooler) than bias ply tires since they offer more flex and better ground contact, thanks to their softer side walls. However passenger car tires should not be used on any trailer application. Special trailer, or ST tires, are the only type of tire that should be mounted on a boat trailer (with few exceptions) since they are made to handle the vertical loads from trailers.

The equivalent tire size to your 155R12 is a 5.30-12. This size tire has an overall diameter (when mounted and inflated) of just under 22-inches and it mounts to a 4-inch wide wheel. The linked page will display all tires and tire/wheel combinations in this size, including the item you referenced, Kenda part # AM30740. Only bias ply tires are offered in this size, please note.

All trailer tires should always be fully inflated to their maximum rated psi pressure, which is noted on the tire sidewall. A trailer tire can deliver its rated capacity only when fully inflated. It is never appropriate to under- or over-inflate a trailer tire.

You can use the filters on the page to choose the weight load range you need and/or the bolt pattern of your wheels if you also want wheels. The linked article shows how to confirm your wheel bolt pattern.

expert reply by: Adam R