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Old 01-03-2016, 01:03 PM   #15
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Ray, thanks for the link to the PDF document. I printed out weighing worksheets. They look to be handy. Also, I don't seem to be able to find a vehicle tire placard in my ten year old diesel pusher. Anecdotally, the previous owner just told me that he was told to run the fronts at 105 and the rears at 85. But then he never changed his load much, other than flat towing a car. I'll be towing a heavy trailer, and I gotta believe my pressures should be different than his as a result. Also, the very reasons you state for most tire failures (over loading and under inflating) is why I'm so hot on accurately weighing and inflating in the context of my coach's and tire's specs. Thanks again for the PDF!

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Old 01-03-2016, 01:04 PM   #16
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Originally Posted by Robmat View Post
January's Motorhome Magazine has an article on this very topic along with pictures, etc. The author went to a CAT scale and weighted the entire MH, then left side and right side and got three receipts and went over them. Pretty good article contain much that was said here.
Rob, I'll scare up a copy of that article. Thanks! Gene

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Old 01-03-2016, 01:19 PM   #17
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Originally Posted by jimbo2013 View Post
You're really doing this without 4 corner weights?

But you want to do right?

You can not just take 50% of the axle.

Find a cat scale and drive one side only on 3 scale tables.
Their is a lot of talk on 4 corner weight, when doing this do you fill each axle tire according to weight (different pressure) or go with the highest weight and fill both axle tire the same PSI?
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Old 01-03-2016, 01:21 PM   #18
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Originally Posted by leesdx1 View Post
Their is a lot of talk on 4 corner weight, when doing this do you fill each axle tire according to weight (different pressure) or go with the highest weight and fill both axle tire the same PSI?

All tires on an axle to the pressure indicated by the weight of the heaviest end.
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Old 01-15-2016, 05:56 AM   #19
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Axle Weights Better Than Nothing, BUT?????

OK, guys. I took your advice. I'm going to get individual wheel weights as soon as I can get them.

In the meantime, axle weights will have to do, AND I have yet another question relative to my tire manufacturer's inflation table and what my tag and drive axles currently weigh. Still makes no sense to me. So here goes...

Drive axle (duals) weighs in at 14,680 lbs. Tag (singles) at 7,340 lbs. Steer axle at 13,460 lbs. So far, so good. The air ride on my diesel pusher is dividing the expected 2/3 of the rear weight to the drive axle and 1/3 on the tag. Cool.

Now, on the Bridgestone R250F 295/80R22.5 inflation table for singles, the actual weight that's on my tag tires (7340/2 = 3670 lbs on each tire), that pressure doesn't even show up on the table (minimum = 5350 at 80 PSI). Does that mean I should run at 80 PSI? Is that even good for the sidewalls of these heavy tires to run that low? And why isn't there even a number CLOSE to the weight I'm actually running per tire? This coach is already pretty fully loaded for an extended trip (lots of clothes, appliances, other "stuff", full water, although only half fuel, empty gray/black tanks).

Same or more confusion on the tag tires. At 14,680 lbs on that axle, divided by 4 gives me the same weight bearing per tire (3,680 lbs). Huh? At max pressure for max load for these tires (125 PSI), the MAX weight rating is 3,150 lbs. Now I KNOW I'm NOT overloaded, AND I still have to add another 1,000 to 1,500 lbs of trailer tongue weight to these two axles (six tires) once I get my trailer back, loaded up and weighed (and yes, corner weights ASAP). UNTIL THEN...

What the heck is the deal here? My actual tag axle weights are WAY BELOW THE MINIMUM RATING on the inflation table (singles line) and WAY ABOVE THE MAXIMUM rating for the drive axle (duals line) on the inflation table.

I'm currently running 105 PSI on the steer axle, which syncs with the table (13,460 lbs/2 = 6,730 lbs per tire = 100-105 PSI per table - cool), but can't figure out this drive/tag axle crap! I'm currently running 85 PSI on tag and drive axles, but that's with no trailer and what the previous owner ran at. I have no placard in the coach and I am NOT to just go with the basic generic manufacturer's recommendation at any rate as I'm not the average user. And I'd like to get this at least close to better PSI's before I hook up the trailer... HELP!!!!

Thanks in advance! And yes, corner weights are coming, just not yet for a few hundred more miles. And no, I have no manufacturer's placard. Arghhhhh

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Old 01-15-2016, 06:14 AM   #20
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I am not much help, I use the motorhome manufacturers suggested psi, it is much lower than the tire sidewall rating.
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Old 01-15-2016, 09:03 AM   #21
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There is debate on this but first a FACT:

I will use an axel weight of 3.000 pounds
This means 1,500 pounds per end. Right... WRONG
It means 3,000 pounds both ends together,
Fact is one end can be 1,000 and the other 2,000 and it will total 3,000

So you really need "4 corner weights" Each wheel (not tire but wheel, duals count as one wheel)

Now the debate

My Position: Each wheel inflated as per company inflation chart (See option)

Other position: Both ends of the axle to the higher pressure, Both ends should be same pressure

NOTE: I can support my position in that the tire's outside diamater effective (distance from center of axle to surface of road) depends on the inflation and load, thus same pressure means the tire with the lighter load is "Bigger" than the one across from it.

I will not defend further.

The Option I mentioned.. Add 5 PSI to company charte, I do this myself.
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Old 01-16-2016, 07:55 AM   #22
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Your weights and dilemma are similar to what I have on a Tiffin Allegro Bus.

My steer axle is heavier, and I run 110 there, per Mfr. Charts for the heavier side.

Tag and drive wheels are similar to your splits, with min required pressures in the low 70 range. I run them at 85. Seems to work well. Steer tires are 295s.
Tag and drive tires are 275s. Going to the larger tires up front gave me a buffer of 10 psi to the max pressure allowable of 120. Has worked well for 3 years and about 20,000 miles.

I would not expect problems with sidewalls, heat, etc as long as you are at the minimum "book" pressure or above for the wheel's weight.
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Old 01-18-2016, 08:06 PM   #23
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OK, like I said, I understand the importance of corner weights (that's six "corners" with a tag axle, right?). BUT until I get to take them, I'm just trying to get my head around the basic math to get an APPROXIMATE PSI relative to the manufacturers inflation table for each tire across each axle for heavier loading BEFORE I hang a 10,000 pound trailer on the rear axles of my coach.

Hopefully, that makes sense to y'all. I just want to get some confidence that I'm not doing something REALLY stupid to my (costly) tires, and I'm just trying to get some clarity with respect to these stupid tables UNTIL I GET MY SIX CORNERS WEIGHED. So until I get those corners, I figure my best guestimate is axle weight divided by number of tires per axle = weight born per tire to yield a best guess PSI per tire based on the tables. Right? Or not? I just can't figure out how to relate the table numbers to my weight approximations. Thanks again for trying to penetrate this thick skull, guys.

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