tire pressure

[Pete Masterson]

The air pressure should be consistent with the load ratings for the
brand of tire and the actual weight of your coach. While the BB
manual has a chart in the owners manual (along with the required
placard), it would be better to use the similar weight/air pressure
chart provided by the tire manufacturer (usually accessible at the
tire company web site).

The placard is based on BB's estimated weight (with the OEM tires) --
you need to weigh your coach to determine the _actual_ tire pressure
required with the normal load you carry. If you check your yellow
pages for "public scales", hopefully you should find a scale
reasonably close by*. You should load your coach as you would for a
trip (full fuel, water tanks as you might normally have them, and
food and baggage on board).

The archives for this group probably have an explanation --- and I've
seen several in RV-related magazines as well --- that explain
precisely how to weigh the coach. You need to know the weight on each
axle and on each wheel left vs. right. You want to be sure that the
left-right load is reasonably balanced and that no axle is carrying
more than its rated weight capacity. You should then inflate the
tires for the weight of each axle per the tire mfgs table. The trade
off is more air pressure will carry more weight -- but more air
pressure will make the ride less-smooth (that's why you don't want to
carry more air than is necessary).

While simply filling the tires to the maximum pressure (as shown on
the sidewall) will certainly ensure that you haven't under-inflated
the tire, it may make your vehicle ride more harshly and may degrade
the handling.

Remember, too, that air inflation measurements must be made when the
tire is at ambient temperature as heat generated in driving will
raise the pressure, potentially causing to be under-inflated when the
tires are cool.

*Note: state-run "weigh stations" generally do not want to see an RV
pull in to their scales. In California, you run a risk of getting a
ticket, especially at a busy weigh station. Some other states may be
more forgiving and/or may even be willing to pull the several weights
you need (axle by axle, etc.) It would be wise to telephone ahead
before pulling into a state-run weigh station.

Pete Masterson
aeonix1@...
'95 Bluebird Wanderlodge WBDA 4203
El Sobrante, CA




On Jul 17, 2006, at 11:57 AM, Alex Smith wrote:

> Hello,
> I have followed several discussions in the past on tires, load
> ratings, and brands. However, not much has been said on tire pressure.
>
> A placard in my coach indicates 105 psi on front and 75 psi on
> rears. Is this the current thinking? 75 psi on the rear tires seems
> a little low esp when max pressure is over 100 psi.
>
> I have gotten some different advice locally, but I'm still
> running with the pressure as shown on the BB placard.
>
> Any comments appreciated.
> Alex Smith
> Tallahassee, FL
> 82FC35
>



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