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Old 05-13-2016, 12:02 PM   #15
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Tire and auto manufactures "ALL" recommend running the same pressure in ALL tires on the same axle.

Unless you can prove me wrong, I would strongly recomend you follow their recomdations.

Running different pressures on your right and left front tires will effect the handling in turns and effect the antilock brakes. It is just like running 2 diferent size tires.

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Old 05-13-2016, 12:08 PM   #16
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Originally Posted by mel s View Post
It is not unusual for the fronts to be inflated to a different pressure than the rears.
However all tires on the same axle should be inflated to the pressure recommended for the tire, (or tires), on that axle that is/are carrying the most weight.
'96 Safari

My point exactly. Front and rear may (or may not) be the same but side to side on same axle should always be the same. I think one of the other posts alluded (at least the way I read it) to inflating each side based on the weight of each respective side. Instead both sides should be inflated the same.

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Old 05-13-2016, 04:08 PM   #17
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Even I am confused reading my own post!! Let's clarify...

Here's a chart from Michelin:


As is mentioned in the text above the chart, match the maximum corner weight (left or right on the same axle) and inflate the tires of that axle the same.

If you're so far off balance that you have a couple hundred pounds difference from left to right you might want to try to move stuff around.

If your scale only shows axle weight, divide by two, find that value on the chart, add 5psi and breathe easy.

My thinking was that the "radial" tire's driving radius is critical. Perhaps it doesn't change due to load as much as I thought. Also, when we're talking around 80psi, maybe +/- 5 is not a problem. All I know is that we started out putting 80psi everywhere and now we're at 65 up front and 70 in the dual rears. Much easier on the bumps and I didn't notice a change in gas consumption.

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Old 05-14-2016, 06:15 AM   #18
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Re: 80psi vs. 65frt/70rr, running minimum psi for better ride? Playing devil's advocate, not sure if you've considered potential side wall flex in cross wind/passing situations? Realize perfectly this is all a big set of compromises.
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Old 05-14-2016, 06:26 AM   #19
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Originally Posted by Lv2Roam2 View Post
There can be a significant difference between the left and right sides of the same axle. A conservative (higher safety margin) approach may be to use the max cold inflation pressures on your tire sidewalls to set your pressures until you get a true 4-corner weight. A less conservative approach is to use your axle weights and set the pressures about 5 - 10 pounds over the chart recommendation to help cover if one of the tires is significantly more loaded (but no higher than the max cold inflation pressure) until you can get the 4-corner weight.

Recommend you talk with the scale folks - they will often know who might have a scale with your needs. A call to local RV dealers may also be helpful. You're on the right track by paying attention to this issue. Safe travels...
This is excellent advice.

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Old 05-14-2016, 09:22 AM   #20
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Trying to learn the actual load on each "corner" of a motorhome is the BEST policy.

HERE is a link to a worksheet that will help you learn the facts.

Class-C may be more balanced than Class-A but still can be hundreds of pounds out of balance side to side on an axle (Slides, location of generator , holding tanks etc).
Lacking corner weights I suggest a quick estimate of 45/55 % split side to side on each axle.

So once you have the numbers for each corner and you consult the charts for your tires. You will know the MINIMUM inflation for fronts (single loads) and rears (dual). Pay attention to the chart as some companies give the loads for each individual tire while others will give the load for the pair of duals. Dual position load capacity is always lower per tire than single position load capacity.

Using the heavier axle end number (or higher load end number if estimating) you now know the MINIMUM CIP setting for ALL tires on that axle.

I then suggest your set pressure to be the MINIMUM pressure + 10% .

Axle scale
F 5,000 R 10200
45/55 F 2250/2750 R 4490/ 5610 <corner loads
Tire loads F2250/2750 R 2245/2805

I would use the inflation for singles that supports AT LEAST 2750# and the inflation for duals that supports AT LEAST 2805# as my MINIMUM

My set pressure for all tires would be the MINIMUM +10%

Hope this clears things up.

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