Comparing weights, front of boggie with rear

[gary j zingle]

"But weighing each axel tells you nothing either as indicated by Cinnabar=
s
research. No two tires on the GMC motorhome ever carry the same weight,
even on the same bogie side."

This is one that has never been properly explained to me.

Given the configuration of the rear suspension (on a stock coach with one=

air bag per side), unless parts were seized etc., it would seem to me tha=
t
the suspension would share the weight very equally between the intermedia=
te
tire and the rear. =


This would of course be limited by scale accuracy and the ability to have=

the coach equally level during the weighing of both axles but both of tho=
se
should be able to be reduced to relatively minor errors.

Can anyone tell me why, given the suspension geometry, on a stationary GM=

(no dynamic forces) the lead and the trailing wheels would not carry very=

close to identical weights?

Regards

Gary Zingle

 

[david l greenberg]

When I had my coach weighed, each time with all six wheels on individual
scales, the results were different for each wheel.

The tanks were all about mid full, and a substitute co pilot covered for
my navigator who was buying everything in sight at the FMCA area rally
just in case we came in too light! Not!

David Lee Greenberg
GMC Motorhome Registry
200 MacFarlane Drive
Delray Beach, FL 33483-6829

 

[thomas g. warner]

Have the front end of mine in the air now and can tell you that when I lower
it on the jack stands I sometimes have to elevate on higher than the other
because the frame will be suspended in air on one side. Dont know about
anyone elses but mine is that rigid. A 1976 Palmbeach.

>I can't believe my eyes. Are you saying that these coaches are so rigid
>that they can be elevated from one side? W O W !
>I thought these coaches were the best designed for their time, but is the
>chassis really that rigid?
>I know I'm just lurking, but come on guys, is this really true?
>Am I just so green that I'm easilly amazed, or is this something special? I
>think it's special.
>But then, after four days of turkey... you know ... you are what you eat.
>
>Larry Davick
>Enviously Lurking
>
>
>>From: Gcbr
>>Reply-To: gmcmotorhome
>>To: gmcmotorhome
>>Subject: Re: GMC: Comparing weights, front of boggie with rear
>>Date: Sun, 28 Nov 1999 22:36:17 EST
>>
>>In a message dated 11/28/1999 7:46:55 PM Central Standard Time,

>>
>> > Back when I first got my GMC (1981) I jacked up one side
>> > using a bottle jack under the passenger side frame member so that I
>>could
>> > remove that wheel and check the brake pads. As I jacked it up all of a
>> > sudden the driver's side wheel also came off the ground.
>>
>>Emery
>>
>>I had a similar experiences when I first got mine. We had pulled it into
>>my friends shop. We wanted to put it up on jackstands so we could do
>>the brakes and brake lines ect. Got the front end up on stands. Went to
>>the back and started jacking on the passenger side rear frame. All of
>>a sudden the coach shifted. There was not much room so we got out
>>of the way----nothing happened. When we finally went back it was
>>balanced on one front jackstand and the floorjack------you could rock
>>it from side to side with one hand. My dragracing friend was cussing.
>>I have interior bracing and a full roll cage and I cant get that kind of
>>rigidity. I now know this is not good for the lady----there were about
>>12 of us here back then.
>>
>>Take Care
>>Arch
>
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>
>

 

[gene]

There is a picture of the scale on my page

look at the rally pictures
gene

>In a message dated 11/28/1999 6:10:51 PM Central Standard Time,

>
>> Front bogie on driver's side: 2000, Rear bogie on driver's side: 2000.
>Front
>> Bogie on passenger side 2150. Rear bogie on passenger side: 2000 This
>gave
>> a total weight of 12650. Taking out the driver (me) gives about 12,400.
>
>Emery
>
>I am finding all of this weight and balance stuff interesting. You said they
>weighed each wheel. Is this scale in a depression or is it sitting on top of
>the ground? If it is sitting on top of the ground isn't it going to make each
>wheel that is on the scale weigh heavy? Was the area where this weighing
>was being done level? I have got a bad theory here. Who was doing the
>weighing?
>
>Take Care
>Arch
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/