85 or 95 PSI??

[classic60]

I recently noted that there is a discrepency between the recommended PSI on the Federal Certification Label on my 2003 Bounder and the PSI shown on the Workhorse "my motorhome" section.

Both show identical GVWR/GVWRF/GCWRR and identical tires but the label shows 85 PSI for the front but Workhorse shows 95 for the front. Which one should I follow?

03 Bounder W22

[edgray]

To be cautious, err on the side of saftey and go with the higher recommendation. The worse that will happen is a harsher than necessary ride.

THEN, please go to a scale and get ACTUAL axle weights loaded the way you travel. Use these real world numbers to determine what pressure you "should" be running.

Anything on a label, other than actual weights, is purely a guess based on some engineering theory. Ed

[Nick-B]

I'm going to make a guess here and say that the Federal Certification label was placed there by Fleetwood and is what they recommend as an appropriate pressure for the weight of the coach "as built".
The Workhorse label is likely stating the maximum inflation pressure for the tire regardless the load weight. Remember, when the chassis builder makes the chassis, they have no control what the final weight will be. That is for the coach builder, so they make the final call.
Look for the "pressure at max load" printed on the sidewall of the tires. Is it also 95 psi? That is the pressure at maximum load, which you are possibly well under.
Ed has the right answer. Weigh it - preferable all 4 corners - and then go to the tire manufacturers web site and find the load charts to determine the correct pressures.

[DriVer]

Quote:

Originally Posted by Nick-B I'm going to make a guess here and say that the Federal Certification label was placed there by Fleetwood and is what they recommend as an appropriate pressure for the weight of the coach "as built"..

Nick-B, That's not a guess, that's exactly how it works. The OEM furnishes the final inflation recommendations based on the weight of their complete vehicle.

[classic60]

I guess what has me just a bit baffled is that the label, almost certainly placed by Fleetwood, shows the maximum weight for the front axle as 8000 pounds with a 245/70R 19.5 G tire at 85 PSI.

Workhorse shows the identical front axle weight and tire but at 95 PSI.

The 245/70R 19.5 G tire's maximum inflation per the sidewall is 110 PSI.

If I assume for a moment (yes, I know what happens when one assumes) that my front axle is loaded to it's maximum rated capacity, prior to actually weighing it, should I go with the 85 or 95?

This 10 pound difference in PSI may not seem like much but I am in the process of putting on new tires, identical in all specs as the originals, alignment and new Koni's so while I want to be safe, I also don't want to over inflate and get a harsher ride than I have too. These California highways are rough enough.

It appears that there is a difference of "opinion" between Fleetwood and Workhorse as to what the recommended PSI is for tires on the 8000 max axle weight. Maybe I'll just split the difference go with with 90 PSI for now.

[George Z]

I would guess the tires are not original and neither are the load pressures going to be. The only way is to weigh and go with tire mfg. suggestions.

[DriVer]

Quote:

Originally Posted by classic60 It appears that there is a difference of "opinion" between Fleetwood and Workhorse as to what the recommended PSI is for tires on the 8000 max axle weight. Maybe I'll just split the difference go with with 90 PSI for now.

That's not a bad strategy BUT the best solution for you is to simply drive up on a CAT Scale, (you can find the locations on the Internet) get the actual weights of your axles, consult the inflation tables in the 2009 Workhorse Chassis Guide, and ADD 5 psi to the indicated inflation recommendation. That's how I roll. You can inflate to the recommended pressure assuring safety and yet only use as much air as you need to promote a comfortable ride.

[classic60]

Currently dealing with some driveability issues detailed under Ghost engine stall so I've been driving from San Diego to Redlands, about 100 miles trying to resolve it so i've pretty much stripped evrything out of the coach and dumped all fluids to keep light. Once I get back into "normal" travel mode, I will certainly get it weighed and inflate from there.

I was primarily curious why, when all things (specs) being identical, Workhorse and Fleetwood differed on the correct PSI for the front. After giving it further thought, I'm gonna take an uneducated guess that Fleetwood was a little more concerned with a smoother more comfortable ride.

[DriVer]

Quote:

Originally Posted by classic60 I was primarily curious why, when all things (specs) being identical, Workhorse and Fleetwood differed on the correct PSI for the front. After giving it further thought, I'm gonna take an uneducated guess that Fleetwood was a little more concerned with a smoother more comfortable ride.

classic60, When Workhorse issued an inflation recommnedation for the bare chassis "most likely" they would recommend that the tires be inflated to the Gross Axle Weight Rating (GAWR).

It is altogether possible that when Fleetwood finished the vehilce they re-wrote the inflation tables to cover the GVWR and weighed the vehilce as it came off the line.

That would probably explain the difference I expect.

[bachler]

If the manufacture States 105 lbs; And the coach manufacture states 90 lbs; so the coach don't rattel and shake to pieces. Which spec are you going to follow; Not to mention The government DOT getting involved; I would Lean to the tire manufactorer, After all it is theres.

[chili's trip]

My Goodyear inflation charts show a 10# plus change for my size tires made after 2006 for the same weight.

[Spikester]

Another thing to consider is the minimum inflation pressure for your tires, 85# sounds like at or near that point. Do not what to run them below the mininum.

Spike

[DriVer]

Quote:

Originally Posted by Spikester Do not what to run them below the minimum.

Spike, Thank you for that. In seminars we learn that tires need to be inflated to the "minimum" pressure that supports the "maximum" load.

[classic60]

And on the subject of proper air pressures, can anyone recommend a quality/accurate air pressure gauge, make, model, source etc.? I have a couple, and even borrowed a neighbor's and they all give me different readings and I'm not just talking about 1 pound or 2 difference.