Tire pressure (max PSI not shown on sidewall?!)

[AndyD]

3901 with Galaxy Marathoner R4 tires. I cannot find a max PSI listed on the sidewall. The only mention of PSI is to not exceed 35 when mounting. I found a catalog with specs online which I believe shows the max PSI for my fronts (27x8.50-15) as 45. I've been keeping them at 30 based on the sidewall, but what planet am I on where the max PSI is not listed on a tire's sidewall, and you have to go to an online catalog to find it? I'm new to industrial/agricultural tires so is there some universal system for calculating PSI from the data on the sidewall?

Also, what pressures are people using for dirt-only machines where traction is important? Our tractor never leaves our property, which is sloped and frequently muddy, snowy, or icy. Used mainly for moving material in the loader, smoothing areas with the box scraper, and plowing snow with a front blade, with chains for rear tires.

 

[jaxs]

I've never seen a tire that didn't have recommended inflation listed on side wall. Is it possible your tire is designed to preform various tasks by changing inflation and that precludes a standard psi? It's common to see tires on say a backhoe with far greater psi than a similar size on an ag tractor. I encourage you to press mfgr for recommended inflation and if they don't come through, inflate to same psi as ag tires of same size and plies. Yes, plies matter, 4 ply can run at much lower psi than 6-8-10 due to sidewall flex.

 

[jimh406]

Fwiw, there isn't any reason to put maximum pressure in a tractor tire. Many people run too much pressure.