Was talking to my former boss today and he mentioned that he was told by the new tire outfit the company has contracted with that we were running the wrong pressures in our tires. He was asking me where I had come up with the pressures that I had marked on the rims of the loader for example. I told him that the pressures I had been using came from either the manufacture of the tire, Bridgestone or Michelin, or right from Cat PSR man. An example for our 980G loaders we have been running 29.5R-25 tires and on the front the pressures we used were 75 psi. This new outfit tells him he should be running 105 psi in the front. My former boss and I agreed that sounds way too high. Since I'm retired I don't have access to a copy of the Cat Performance Handbook, forgot to liberate one of those on my way out the door I suggested he contact Cat and the tire companies direct, but just wonder if anyone else thinks these pressures are excessive. I know from years back when I had Corvairs one big problem people had with them was some tire jockey putting on new tires and inflating the fronts to the pressure on the sidewall, believe 32 psi was the standard back then. Well due to the light weight of the front end that car that was twice what they should have in them. At 32 psi they were like hard rocks and offered no traction and being bias ply that did not help!
I delved into my Bible and numbers from previous job sites. Here's what I came up with for a 980G equipped with 29.5R25 1-star load rating TRA L-4 or L-5 radial tyres: - Michelin - 60F/40R Bridgestone - 70F/55R Goodyear - 60F/40R These pressures can go up by at most 10psi depending on site conditions. I only have a Michelin Data book but the absolute max pressure for a 29.5R25 1-star that should never be exceeded is only 80psi.
That sounds like what I was recalling, I'll pass that information on to my former boss in the morning. Would like to know where this guy got the 105 psi pressure from, unless that was a normal pressure for the old bias ply tires back in the 1960's??? The more I think of it I think I'll forward that information to his email address right now!