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Tire PSI Settings


FWGERHART
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Fred,

Before anyone can help you with the correct psi for your tires more information is needed such as:

Corner weight of each corner of the coach when typically loaded for travel. If not corner, minimally you should have axle weights.

Model and size of the tires, (brand is Michelin)

If none of this critical information is known then inflate the tires to maximum cold psi as recommended on the side of the tire & wheel.

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5 hours ago, FWGERHART said:

I just installed 6 new Michelin tires. 2 front. 4 rear. I want to set the PSI accurately. What is the recommendation? PSI cold. Thank you

Weigh the coach. Four , or Six corner weight is the best, but single axle weights will be OK too. Fuel and water full. Black and grey tanks empty with your stuff on board. CAT scales at many truck stops. Tell the clerk you want to weigh a coach. There is an intercom at the scale so you can communicate with the clerk. There will be -3- platforms for -3- axles. Steer axle on the  first, Drive on the second, and if applicable, Tag on the third. Get the print out from the clerk. IF you have a tag axle, you may have to adjust your DOWN pressure to move weight as needed, and after adjusting your down pressure on the tag, REWEIGH the coach.  Now go to YOUR tire Mfg. inflation charts for the correct COLD inflation.
Tire Inflation Tables
 
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Edited by Paul A.
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My Owners Manual goes into the calculations once you get the individual wheel weights.  You will need the Manufacturers Pressure chart for that specific tire.  There is no "general" tire pressure for everyone, since tires are different, and the weight each tire supports is different for each person's coach.

 

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18 hours ago, Paul A. said:
Weigh the coach. Four , or Six corner weight is the best, but single axle weights will be OK too. Fuel and water full. Black and grey tanks empty with your stuff on board. CAT scales at many truck stops. Tell the clerk you want to weigh a coach. There is an intercom at the scale so you can communicate with the clerk. There will be -3- platforms for -3- axles. Steer axle on the  first, Drive on the second, and if applicable, Tag on the third. Get the print out from the clerk. IF you have a tag axle, you may have to adjust your DOWN pressure to move weight as needed, and after adjusting your down pressure on the tag, REWEIGH the coach.  Now go to YOUR tire Mfg. inflation charts for the correct COLD inflation.
Tire Inflation Tables
 
RVSEF Home
RVSAFETY.COM
RVSEF Home

Then only way to do it, Period !!!

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1 hour ago, moxy1962 said:

Then only way to do it, Period !!!

Agree!  My comment regarding the accuracy of my placard was confirmed only after weighing. Should have been clear on that

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Hi There:

I suspect numerous tomes regarding tire pressures/weighing rig have been written/read over the years! So, as a newby, I took my Monaco Dynasty D4 to a CAT scale and had it weighed. The weights were: Ft Axle - 13840 & Drive Axle - 25000.

Because I have a drive & tag axle, should I have positioned the rig so my drive axle was on the back edge of table 2 & my tag axle on the front edge of table 3? Will CAT scales weigh accurately when the wheels are not centered on the tables?

Also, I've read tomes about the superiority of "four corner" scales. Is there really that much difference b/t a four corner & CAT scale when it comes down to determining tire pressures?

Thanks

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36 minutes ago, Newcsn said:

Is there really that much difference b/t a four corner & CAT scale when it comes down to determining tire pressures

My 04 Dynasty Diamond 4 was well balanced so hopefully your 06 is too. Yes, it makes a difference if one side is 1000 lbs more than the other. I go +5 psi over the load table because I’ll travel with heavy crosswinds which shifts a lot of weight.

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It depends on loading.  You can add over 3500 pounds to most Dynasty's and it defilement on house you load it.  My front axle is within 300 pounds side-to-side, but my drive is almost 1000 pounds different.  The floor plan and basement configuration doesn't make it easy to even out the weight.   Bottom line, you would use the highest weight on each axle to determine the tire pressure for BOTH sides. 

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5 hours ago, Newcsn said:

Hi There:

I suspect numerous tomes regarding tire pressures/weighing rig have been written/read over the years! So, as a newby, I took my Monaco Dynasty D4 to a CAT scale and had it weighed. The weights were: Ft Axle - 13840 & Drive Axle - 25000.

Because I have a drive & tag axle, should I have positioned the rig so my drive axle was on the back edge of table 2 & my tag axle on the front edge of table 3? Will CAT scales weigh accurately when the wheels are not centered on the tables?

Also, I've read tomes about the superiority of "four corner" scales. Is there really that much difference b/t a four corner & CAT scale when it comes down to determining tire pressures?

Thanks

You will get an accurate weight where ever your axle is on the platforms[tables].  Just stradle the drive and tag axles between the 2nd and 3rd platforms. When adjusting the Down pressure on the tag, the Drive axle becomes a fulcrum point and you move weight to/from the front axle,  to,  to/from the tag axle, by raising/lowering the Down pressure. The weight on the Drive axle is minimally effected. Just like a teeter totter. Remember?

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10 hours ago, Paul A. said:

You will get an accurate weight where ever your axle is on the platforms[tables].  Just stradle the drive and tag axles between the 2nd and 3rd platforms. When adjusting the Down pressure on the tag, the Drive axle becomes a fulcrum point and you move weight to/from the front axle,  to,  to/from the tag axle, by raising/lowering the Down pressure. The weight on the Drive axle is minimally effected. Just like a teeter totter. Remember?

Thank you Paul A! This makes perfect sense!

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11 hours ago, Paul A. said:

The weight on the Drive axle is minimally effected. Just like a teeter totter. 

Sorry but the opposite is true. If you increase the weight on the tag 1000 lbs, the drive decreases 1200 lbs and the steer increase 200 lbs on a 45’ rig. There is no fulcrum in the middle, it’s a arm and  it’s on a 280” to 44” ratio …6/1 approx.

Edited by Ivylog
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On 10/14/2021 at 6:35 AM, Ivylog said:

Sorry but the opposite is true. If you increase the weight on the tag 1000 lbs, the drive decreases 1200 lbs and the steer increase 200 lbs on a 45’ rig. There is no fulcrum in the middle, it’s a arm and  it’s on a 280” to 44” ratio …6/1 approx.

Sorry, i did not state there is a fulcrum in the middle. And, you can not increase the weight on the tag AND steer buy increasing the weight on the tag. I would like to see those weight transfers on a scale weight print out.  

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I’ve helped enough people adjust their tag pressure to know what happens so I’ll let you go to a scale and see what happens when you increase the tag’s pressure. “Just like a teeter totter.” is where the fulcrum in the middle came from. I do like someone who doubles down.

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On 10/17/2021 at 2:18 PM, Ivylog said:

I’ve helped enough people adjust their tag pressure to know what happens so I’ll let you go to a scale and see what happens when you increase the tag’s pressure. “Just like a teeter totter.” is where the fulcrum in the middle came from. I do like someone who doubles down.

And, you can not increase the weight on the tag AND steer buy increasing the weight on the tag. I would like to see those weight transfers on a scale weight print out. 

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Sorry Paul but you are incorrect. Increasing pressure on the tag will certainly increase steer axle weight. I don’t have my scale weights at hand but I can tell you with certainty that this is indeed the case. 

Edited by Chargerman
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22 minutes ago, Chargerman said:

Sorry Paul but you are incorrect. Increasing pressure on the tag will certainly increase steer axle weight. I don’t have my scale weights at hand but I can tell you with certainty that this is indeed the case. 

IVYLOG said it. This is his statement; "Sorry but the opposite is true. If you increase the weight on the tag 1000 lbs, the drive decreases 1200 lbs and the steer increase 200 lbs on a 45’ rig. There is no fulcrum in the middle, it’s a arm and  it’s on a 280” to 44” ratio …6/1 approx."

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On 10/14/2021 at 7:35 AM, Ivylog said:

Sorry but the opposite is true. If you increase the weight on the tag 1000 lbs, the drive decreases 1200 lbs and the steer increase 200 lbs on a 45’ rig. There is no fulcrum in the middle, it’s a arm and  it’s on a 280” to 44” ratio …6/1 approx.

It’s actually the inverse square logarithm double the distance quadruple the force or conversely halve the distance decrease the force by 75%, and adding 1000 lbs of force with no physical changes cannot create 1200 lbs of force unless You can change the laws of physics 

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5 hours ago, Paul A. said:

And, you can not increase the weight on the tag AND steer buy increasing the weight on the tag. I would like to see those weight transfers on a scale weight print out. 

This is what I was referring to. The fact is the opposite is true. Increase tag pressure and steer will get heavier while drive axle will unload. 
I can attest to this by my experience although as previously mentioned, I am not close to my scale readouts to show proof. 

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