Question of motor home tires.

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Green

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Jun 12, 2005
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6
???? I'm fairly new to the forum, and I have tried not to ask silly, nonsensical questions, and I hesitate to ask this one, but I'm concerned about something regarding tires. When I bought the Class A last year the dealer simply said to keep psi to what the side of the tire stated, nothing else considered. That is 120psi, and that is what I did for awhile. During the last year I have put 10,000 miles on the tires.? Also during the last year I have read countless articles about the importance of weight vs psi. Somewhere down the line someone said to simply have 115 PSI, in all tires. Even though I knew that to be incorrect, I did that anyway. Recently I went to Freightliner for 12 month maintenance and was told I needed a tire rotation. That was done, and when I checked the air in all tires afterwards, they had gone with 105psi all tires. Then I go to a tire dealer just checking about what I am about to ask here.? He said they put no more than 100 in any of the tires they change/rotate/sell etc.? So, I went with 100psi rear, and 95psi front. My tire size is 255/70R22.5
? ? ?Now here's my silly question:? ?Each time I have adjusted tire pressure according to the so called experts, there has something strange happened. When I pull out of my garage with the motor home, there are black marks in my drive, and for 2 blocks from home I see the black marks whereever I turned a corner, and yes, I'm sure they are my marks.. This lasts for several trips, and happens after each pressure adjustment. I know, this is probably stupid, but is there something about these big RV tires that shows rubber left on the street and driveway. It has me concerned and confused as to how much tire pressure I should be actually going with, and if what I'm doing now is wearing too much tire.? thanks for some help.
 

Tom

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Jan 13, 2005
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48,620
There are no silly questions around here.

Please click here for an explanation of how to correctly determine your tire pressures.
[edit]Link update[/edit]
 

Ron from Big D

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Jan 30, 2005
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Dallas, Texas
There is only one sure way to set your tire pressures.  Have each wheel position weighed individually and then refer to tire chart provided by the manufacturer.  They will set the tire pressure for the weight.  If you have a difference in side to side weights, set the pressure according to the highest weight on that axle. 

If you can't find someone to weigh each wheel separately, then go to a scale that will weigh each axle.  If there is space to the sides of the scale, then weigh with only one wheel per axle on the scale and subtract it from the total axle weight in order to get the individual weights.

If there is more than a couple hundred pounds separating the weights on each side of the coach on each axle, then you need to redistribute your loads in the coach to get them as even as possible.  It will pay off in great dividends.  Also, make sure your coach is not overloaded at all positions.

When you weigh the coach, have if full of fuel and water along with what you normally carry during a trip.  Even include the people load or compensate on the wheel positions for them.

 

Ron

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Home is where we park it
Excellent Question and Tom has provided a link to the correct answer.? When a so called expert tells you something different then you next question should be:? Why do the tire manufacturers provide weight / pressurization charts.? A good video to watch is put out by Michelin but applies to all tires.? I highly recommend viewing it.? It can be found HERE

Like Tom said there are no silly or stupid questions.? I sometimes use to tell my flight students that "The only stupid question would be the question not asked."
 

Karl

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Mar 3, 2005
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Elkhart Lake, WI for the summer. Work at Road Amer
When I pull out of my garage with the motor home, there are black marks in my drive, and for 2 blocks from home I see the black marks whereever I turned a corner, and yes, I'm sure they are my marks.
It is NOT normal for tires to leave marks, and merely changing pressures shouldn't cause it.
First off, you need to determine if the marks are actually rubber marks or something else you may have dripping on them or have driven through. Is it an occasional patch, full/partial width, can you see the tread pattern or is it blurred - or anything else you can add to determine exactly what's going on. Then figure out which wheels caused the marks - front, rear, right, left. If it's fronts, you may have a severe alignment problem that's causing the tires to scrub the pavement. Is it hard to steer? Does the steering wheel return to center after a turn by itself? Fronts or rear brakes may be dragging. Does it seem like it takes a lot of power to get moving? On some vehicles, the rear wheels need to be aligned too, but I don't know about yours specifically.
 

John From Detroit

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Apr 12, 2005
Posts
24,782
Location
Davison Michigan
Generally the only way tires will leave those kind of marks (and there are two ways) are

1: If you are "Pealing Out' or "Burning Rubber" and since a class A motor home, at least the ones I've seen, is NOT a hot rod I don't think this is happening

Method 2 involves driving over fresh asphalt or blacktop and the marks being left are actually that substance which covered the tire as you drove across it.

Oh, yes, there is a third method... it is the same as 2 but a different "Black stuff"
 
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