Recommendation to Replace ST145/70R12 Tires

Updated 03/25/2019 | Published 03/23/2019

Question:

Hello, I have a 6 year old trailer and I want to replace both tires for preventative maintenance. The trailer has ST145/70 R12 tires on it and I have a new never used spare with that same dimension. I am trying to find another exact same tire so I just use my spare and another new tire but finding it extremely difficult to find this tire Carlisle. Can I use a 5.30x12 tire on one side of the trailer and my ST145/70 R12 on the other? Worried about the size of tires but also the tread design is different. Or should I just keep that spare tire and buy two new 5.30X12 tires? Appreciate your help with this.

asked by: Eric H

Expert Reply:

You definitely don't want to use different sized tires because it will cause your trailer to sit uneven and will cause uneven wear both on the tires as well as your trailer suspension and who knows what else. I really wouldn't advise using that as a spare unless you are only going to be traveling a very short distance for repairs (like within a mile).

I personally recommend going with the tire size 145/80-12 because these come in radial which are much better for highway use than bias tires are. The Kenda Karrier S-Trail # AM31199DX is a great option that has a load range D (1,220 lbs at 65 psi), a max speed rating of 65 mph, and comes with a white spoke wheel with a 5 on 4-1/2" bolt pattern.

expert reply by: Jon G