Hello, I am getting my 77 Barth ready for its maden voyage and would like to know what tire pressures you guys run in your Barth on a P30 Chassis. I replaced all the tires, installed Bilstien shocks and polly anti-sway bar bushings. It now handles great but has a very harsh ride in the rear over minor bumps in the road. I am now running 60PSI in all the tires just as a starting point but thinking this may be too high and a lower pressure may help absorb the minor bumps better. Any advice?
Neil.

What size, brand and load rating are the tires?

Kumho Road Venture 235/85R16 Load Range "E".

First, you must load the coach as if for travel and weigh each wheel. Then you use a chart for inflation. All wheels on the same axle must have the pressure demanded by the heaviest loaded wheel. I like to add 5 pounds to the manufacturer's chart. Some like 10 pounds over.

Kumho seems not to provide a chart, and weasels around on their web site, mentioning only vehicle manufacturers recommandions.

Most tire manufacturers publish a chart giving weight carrying ability for a certain pressure.

I was not able to find one for Kumho, but you might be luckier or more thorough than I.

You could always use a Tire Guide for a similar tire and follow those recommendations.

I am referencing Chevrolet Motor Home Chassis Service Guide, Pub No ST-372-86-MH printed by Chevrolet for the P-30 Motor Home Chassis. For your LT 235/85R16 their chart lists the following:
Load Limit of 2623 lbs inflate to 65 psi for single wheel installation. For dual wheels the load limit is 2105 at 65 psi. At 2425 lbs single and 1918 lbs for duals the pressure is 58 psi. They descend from there. On my SOB built at the same size and year the only solution for the harsh rear jounce was to install Firestone Air Bags and they are readily avaliable - they changed the whole ride, but still not nearly as good as the big Barth.
You might be able to order the book from Chevrolet as it goes up to 1985 or find it on line.
Tom

That loading might be a bit light for a gaso puller - my 28' Breakaway DP scales in loaded at 5,250# on the front axle, and the only engine up front is the genset. That would imply that Load Range F tires are appropriate on the front axle, or that the tires be inflated to their sidewall max.

So I thoroughly agree with what bill h says - that coach MUST be weighed to determine what the actual loads are.