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Old 12-19-2016, 06:39 AM   #1
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Determine tire psi using MH weight?

How do I determine recommended tire pressure based upon MH weight?

Planning to have our 'new to us' '01 Allegro Bay 36DB weighed in the near future to obtain not only gross weight but actual weight on each axle. I went to tire manufactures web page but couldn't find any information other than what is already printed on side of tire.

Sailun, S637, 245/70R19.5, max single 4540 lbs @ 110 psi, and max dual 4300 lbs @ 110 psi.

Been running 95 psi in all 6 tires simply because that was the pressure in tires when we purchased MH in Aug 2016.
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Old 12-19-2016, 06:52 AM   #2
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Look around the tire web site. Every manufacture of decent tires will have an inflation guide. Well I checked and Sailon is not one of them. Then I would use a similar tires inflation chart. I would also exclude Sailon from the list of available replacement tires.

Once you have the per-wheel weights, look up the weight for your tire and use the next higher number. You might add add few lbs for margin.

Remember, when the tire is in a dual location (rear axle) there is a different set of numbers in the table.
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Old 12-19-2016, 09:24 AM   #3
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Determining the proper pressure for your tires is a pretty easy process.

1. Load the coach as if you are going on a trip (that includes passengers)
2. Drive to your nearest CAT scale (most truck stops have them). Leave the toad at home for this one.
3. Pull up on the platform, push the button and talk to attendant. They will tell you when you can pull off.
4. Go inside and pay your $10-$12 and get your weigh slip. Go ahead and drive home.

Calculating your pressures:

Your coach is an imperfect beast. It does not weigh the same on each tire as its weights are not evenly distributed side to side or front to rear. You are going to use a little arithmetic to compensate for some of these weight differences.

Take your front axle weight multiply by 1.05. Divide the resulting number by 2. Look this weight number up in the tire manufacturer's inflation chart for your exact size of tire. I would then add 5 psi to that number as a fudge factor. When your tires are cold, inflate to that pressure.

Do the same thing with the rear axle. Make sure you use the inflation chart for dual tire configuration as it will give you the tire inflation pressure for each tire in the pair.

The 5% used in the calculation is to compensate for side to side differences in weight. The 5 psi is a fudge factor for unforeseen varying weight loadings, etc.

Individual weights are fine, if you can get them. However, you still inflate all tires on the axle based on the heaviest wheel position (kind of like the 5% adjustment).

If you are looking for tires, I suggest that you look at Toyo, Hankook, Bridgestone, and other commercial truck tires.
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Old 12-19-2016, 09:37 AM   #4
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Quote:
Originally Posted by Dale & Mark Bruss View Post
Look around the tire web site. Every manufacture of decent tires will have an inflation guide. Well I checked and Sailon is not one of them. Then I would use a similar tires inflation chart. I would also exclude Sailon from the list of available replacement tires.
I've never been able to find an inflation guide for my Dunlop tires.
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Old 12-19-2016, 03:06 PM   #5
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I've never been able to find an inflation guide for my Dunlop tires.
http://r.search.yahoo.com/_ylt=A86.J...gLCj7pSUf3GhA-
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Old 12-20-2016, 08:41 AM   #6
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The lower tier tire brands often lack full information on their websites, but you should be able to get a tire inflation table for the brand & size at a dealer who sells them. They may not immediately know where they are, but the dealer has them, or access to them, if you ask. Too many dealers don't bother to use them, though. They often have a "one psi fits all" process.

If they don't recognize "tire inflation chart", ask for the "tire data book" for the brand. It will have load & inflation info.
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Old 12-20-2016, 06:05 PM   #7
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Thanks for all the replies!
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Old 12-20-2016, 06:10 PM   #8
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Here is what my owners manual says about tire pressure:
Quote:
Tire Industry Changes
The tire industry, as a whole, has changed its traditional stance on adjusting cold tire inflation pressure for RV tires installed on recreational vehicles and busses. Previously, tire manufacturers supported a policy where tire inflation could be adjusted according to the actual loaded weight of the vehicle. Now, the major tire manufacturers recommend that medium duty truck tires be maintained at the pressure that corresponds to the Gross Axle Weight Rating for the axle to which they are mounted. To make this recommendation uniform across the industry, tire manufacturers strongly urge the consumer to keep all tires inflated to the pressures recorded on the Federal Tire Label.

Tire Inflation
Country Coach recommends that the cold tire inflation pressures should at all times be maintained at the inflation pressure(s) recorded on the Federal Tire Label. There are no acceptable circumstances where tire inflation pressure(s) should be reduced below that pressure recorded on the Federal Tire Label.
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Old 12-20-2016, 06:16 PM   #9
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Interesting that FB blocks that link.
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Old 12-29-2016, 08:20 AM   #10
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Quote:
Originally Posted by F4Gary View Post
I've never been able to find an inflation guide for my Dunlop tires.
You can use Goodyear or Bridgestone charts for almost all brands EXCEPT Michelin where you need to use their charts. Also pay attention as some charts show load by tire some by axle end and some by axle
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Old 12-29-2016, 09:44 AM   #11
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Tireman9,

Can you tell me what TPMS you use?
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