Originally Posted by brucemc
The max weight rating on the 4500 is 14K lbs; our running weight is 10850lbs. We still have a touch over 3000 lbs capacity, but it would depend on each Gross Axle Weight, of which I don't have the numbers handy at the moment.
Generally, tire pressure is subjective, to a point. A minimum pressure is required depending on the weight the tire is carrying. For example, our unit weighed in at the following 2 weeks ago at the conclusion of our maiden voyage:
3400 LR /2=1700
3300 RR /2=1650
Therefore, looking at the pressure tables at Michelin (which applies to all brands - this is a federal standard rather than a Michelin standard) for LT225/75R16 E: Michelin RV Tires | View Michelin RV Tires load and inflation tables for motorhomes and recreational vehicles. | Michelin RV Tires
Pressure Load position
51 1950 LF
52 2000 RF
42 3400 LR /2=1700
42 3300 RR /2=1650
Note these are the minimum pressures for those loads. I tend to run more pressure to firm up the tires for handling and ride, but not so full that they become harsh. We are still experimenting, but we ran 65Lbs in each tire the first trip. I felt the rears were fine, but the front seemed a little soft.
Help that hopes!
In general the Load & Inflation tables you find will be correct for about 97% of the tires on the road. However in my experience the Michelin brand has the most exceptions. This is because they sometimes use tires designed in Europe using Metric dimensions, calculations before rounding.
If you can find a table for your specific brand then follow that table. If you have tires from a company that does not publish tables on the internet your dealer should be able to provide. If the dealer doesn't even understand the question of Load & Inflation table you need a different dealer. In the meantime you can use just about any table and can expect to be withing a couple %.
IMO you should run 10% more inflation than the minimum needed to support the measured load on the heavier end of the axle.
I write a blog on RV tire application and safety. RVTireSafety.com
Also give seminars on tires at RV events across the US. 40 years experience as tire design & quality engineer for major tire mfg. Freelander 23QB on Chevy chassis is my RV