TIRE PRESSURE

[Terry Henricks]

MAKING FIRST TRIP THIS WEEKIND IN NEW TO ME BEAVER.  TIRE PRESSURE FRONT 115lb, REAR 100lb, TAG 90lb.  DOES THIS SOUND OK? HAVE NOT HAD IT WEIGHED.

THANKS TERRY

[Bill Sprague]

You are in the right range.  But, and it is a big one, you are the only one that can figure it out.  

Get the chart for your brand of tires.   Weigh your coach.  Many say you must weigh it at each wheel.  

If you don't weigh it, you might want to assume you are loaded to the maximum for each axle.

I have driven over scales enough times that I, know my axle weights.  I rounded up a little and then use the tire pressure charts.  The Goodyears I had required a different pressure than the Michelins I now have.  You need the charts.  

I bought the Michelins from a large tire store that sold lots of motorhome tires.  I asked the tires be filled according to the chart in the book they gave me.   I provided the weights.  They wouldn't do it.  Apparently the store decided their liability was reduced when they inflated the tires for maximum capacity.  I had to drive a block and let some air out to get to the chart figures.  

[Gerald Farris]

Terry,
If you do not know the wheel weights for your coach, I would inflate the tires for the maximum weight rating for each axle until you have the coach weighed with it loaded the way you travel.

Remember, an overinflated tire will just ride a little rougher, however an underinflated tire will blow-out. So if you are going to guess on the weight and therefore the inflation pressure, guess high. It is much safer.

Gerald  

P.S. Always use the tire manufacture's inflation charts.

[Keith Moffett]

We have the Mischelin XA2 front and rear.  105 - 110 front and 95 all duals.  No tag.   Had her weighed at a rally to reach this pressure value.
Safe trip.
Keith

[Richard And Babs Ames]

http://rvsafety.com/ RVSEF has good tire and weight information.

[Jeff Watt]

 :)Re-Posting this as I have basic question regarding the tag. From my weights (below) the tag is well within limit and drive is as well. If the tag pressure is decreased then I  gather the weight on the drive will go up. I also believe that if the tag is decreased then the front may decrease as the tag "pushes" on the front, i.e. weight transfer. I think I will decrease the pressure on my tag as it seemed high given the weight it was carrying. I have to re-weigh it but the manual doesn't really specify an optimum balance amount. Any experience?

Finally weighed the coach May 24. Scale is in kg (#s are converted from kg) and I could only weigh curb side and total axle so drivers is the difference. Full fuel, 35 gal water, 17gal propane.

Tires front Michelin X coach 295/80 22.5 max 7830 @123psi.  
Rear Goodyear G670RV 295/80 22.5 max 6940 @125psi dual  
tag Goodyear G670RG 295/80 22.5 max 7830 @ 125 psi.  

Front Axle 14462; curb 7451; driver 7011;    GAWR = 15300
Drive Axle 17,505; curb 8973; driver 8532;    GAWR = 21000
Tag Axle 6393; curb 3130; driver 3263;   GAWR = 10000

Tag set @48 psi which I think this is too high; PO had a big trailer with a lot of tongue weight. I tow an Explorer which has little downward tongue weight.

It is more or less loaded except for food, clothes and us. The front weight is with me in it. With these weights,  I am within limits, although front is close and with full water the front may be near limit.

I have pressures set at 115 front and 90 at tags. According to the pressure chart, my front is about right but could be set a bit higher. The drive and tag are set a bit high.

Thanks,

Jeff

[Keith Moffett]

Jeff
You might note the other thread on the forum regarding towing an Explorer.  As that is what you tow I would be interested in your input on that thread.
Thanks
Keith

[Terry Henricks]

Finally got it weighed.  Front 1400lb, rear 21821lb. total 36360lb. Tires are goodyear front G395 295/75R 22.5.  Rears and tag are MARATHON LHS 295/80/22.5.  Cannot find date on tires.  Do not know why front and rear size different.

Terry

[Dennis Kitchens]

Your tire date is probably on the insde of your tire. They only go on one side at least any I have seen have been that way.

[Terry Henricks]

GERALD, DO THESE WEIGHTS SOUND OK?

[Gerald Farris]

 Terry,
The front axle weight that you posted of 1400 lbs., I assume is a typo and you meant 14000 lbs. If so you are overloaded significantly on your front tires. If you go to the Goodyear Truck Tire Inflation Tables http://www.goodyeartrucktires.com/pdf/resources/publications/2010_loadinflation.pdf   you will see that the maximum load for a 295/75R22.5 is 6610 lbs.at maximum inflation of 120PSI. That puts each front tire 390 lbs overloaded if the coach is perfectly balanced from side to side and they virtually never are, and that is the reason that you get weights for individual wheels.

The rear wheels are well within your weight range if you meant that the drive axle and tag together are 21821 lbs. If that is true, you can take some of the weight off of the front axle by reducing the weight on the tag and letting the drive axle carry more, however I do not think that you can take 1000 lbs off of the front axle, and you probably need at least that much of a reduction with the front tires that you are running.

The other alternative is to move the front tires to the tag axle and the tag axle tires to the front, assuming they are in good condition. Your front tires will carry the load of your tag axle very well, but I would not consider using them on an axle that is loaded to 14000 lbs, especially a steer axle.    

Gerald

[Terry Henricks]

THANK YOU VERY MUCH. I'M GOING TO WEIGH IT AGAIN. I REALLY DON'T HAVE ANYTHING UP FRONT TO BE HEAVY UNLESS THATS THE WAY THEY ARE WITH ALL TANKS FULL. DO I LEAVE TAG DOWN OR UP? WHAT PSI DO I NEED IN TAG? THANK YOU GERALD.CAN I FIND OUT WHO OWNED THIS BEFORE ME?

[Robert Mathis]

Terry, you really need to find a way to weigh each wheel seperately, or at least each axle. I use a Florida DOT scale nearby, and they put each axle on a seperate part of the scale. I adjust the air pressure on the tag until I balance the axle weights. When you add air to the tag, it takes weight off the drive axle and adds it to the steer axle. It's trial and error on each coach.

[Richard And Babs Ames]

I have talked to the Mobile DOT enforcement officers and they will set up a weigh station at a rally for you if you like. They have the portable individual wheel scales like RVSEF uses.