same markings, but different sizes? (1 Viewer)

[toy4xfun]

Yesterday the wife went to get a load of mulch in our Snow Bear trailer, she calls me and says the tire is flat,(no big deal one tire has a slow leak) so i go over and put air in it. As i am filling it up i notice a huge bulge, well the belts had separated in the tire, so i told her to drive slow and followed her. The tire blew out about a mile from the house. Now to my question, she went and got a new tire the same markings as the old ST175/80D13 but it is larger in diameter than the old tire, also the old tire took 50 psi and the new only takes 32 psi. Why is this?

 

[PAToyota]

Different load ranges? Different manufacturers?

 

[Rubiconcruiser]

This is typical and the tire is more than likely Chinese.

 

[Mark Harley]

Biased ply verses a radial tire?

 

[toy4xfun]

the load range is a B on the new tire, i have to find it on the old one.

 

[cruiserpilot]

Yesterday the wife went to get a load of mulch in our Snow Bear trailer, she calls me and says the tire is flat,(no big deal one tire has a slow leak) so i go over and put air in it. As i am filling it up i notice a huge bulge, well the belts had separated in the tire, so i told her to drive slow and followed her. The tire blew out about a mile from the house. Now to my question, she went and got a new tire the same markings as the old ST175/80D13 but it is larger in diameter than the old tire, also the old tire took 50 psi and the new only takes 32 psi. Why is this?

Check the load rating of the tire. As you know not all tires marked the same are the same size. Check the brand and manufacture date, you don't want to buy a tire that's brand new and has been sitting on the shelf for 10 yrs.
ST means trailer only. D means bias ply.
Typically a "C" load range is equivalent to a 6 ply rated tire, "B" is a 4 ply, "D" is an 8 ply and "E" is a 10 ply rating. So 32 psi is a low load rating.
You'd be best to replace both tires at the same time, get the same load rating and tire compound. Trailer tires are subject to sidewall breakdown as they sit alot. I hope this helps, good luck.