Correct Inflation Pressure for Trailer 4.80-12 Trailer Tires

Updated 08/10/2026 | Published 07/17/2017

Question:

What if the tires I have say trailer tires but are not marked ST? Do I still inflate to Max pressure. Carlisle 4.8 - 12.0 sport trailer

asked by: Rad M

Helpful Expert Reply:

Tire size 4.80-12 is not found on vehicles, but is a common trailer tire size on smaller utility- and sport-type trailers. In trailer use you do want to inflate them to the maximum cold psi pressure noted on the tire sidewall. Trailer tires should never be under- or over-inflated since they can deliver their rated weight-carrying capacity only when inflated to their specified pressure. Incorrect inflation can lead to excessive heat which is the main cause for tire failure.

All of our tires in this size are shown on the linked page; note these vary in their rated pressure. Most require 90-psi but a few are rated for 60-psi.

expert reply by: Adam R

Tom F.

5/19/2025

Thank you for a quick summary of what I needed to know a lot of webpages don’t do that

Nick S.

5/21/2025

@TomF It is great to hear we were able to help you out Tom! Did you have any follow up questions about what you are looking for?

T F.

5/21/2025

It also says that 450 pound weight so that trailer with two tires can carry 900 pound maximum

Jameson C.

5/21/2025

@TF Yes that is correct.

Mike V.

8/5/2026

I understand what’s being said here, but I’ve got Calista’s 4.80-12 with a load rating of C. It says 90 psi on the tire with a weight rating of 990lbs a piece. I converted a jet ski trailer to a kayak trailer and my max weight loaded is 650lbs. Do I really need to max out the tires when I’m 1300lbs below the load these tires are meant for? Thanks.

Jameson C.

8/5/2026

@MikeV I know it sounds excessive but it's still recommended to run the max psi at all times. Otherwise the tire will heat up and then potentially fail.

Mike V.

8/7/2026

@JamesonC thank you.