| Re: The impact of extra weight on GMC handling [message #327201 is a reply to message #327154] |
Sun, 17 December 2017 04:55   |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma:
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Senior Member |
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There is a lot I, and perhaps we, don't know about the Princes coach. Perhaps it was as simple as an out of center box. Cinnabar did the chassis work. I'm not a Cinnabar fan but would THINK they know enough to check that....or perhaps not. Like I said, I'm not a fan...some of you are. I'm going to be up in Goshen IN next fall. Perhaps I'll be able to talk the museum into letting me pop the hood and check the steering box center.
Regardless, yall are missing my point...not that I'm suggesting I'm right and anyone is wrong. As I said, I'm not an engineer and might be as full of it as a Christmas turkey.
Let me restate my theory:
-I know that EVERYTHING MOVES. Skyscrapers, massive steel beams, concrete slabs, you name it...they all deflect with enough force.
-I know that our bogie arms move. I've seen it, we've all seen it any time we turn in a parking lot and look in the mirror.
-I know that the bogie arms are a cantilevered load. That is the bogie bushing is not in line with the tire (load) and that means that the bogie arm is subject to a twisting load that varies based on weight. The more load is on the bogie pin (heavier the rear of the coach is), the more that weight tries to twist the bogie arm. An analogy is holding wheelbarrow handles while someone adds weight to it. The wheel is the fulcrum and is the same as the bogie pin. The handle is the offset tire and the load you feel when someone dumps a bag of rocks in the wheelbarrow is the same as the increased twisting force on the bogie arm.
-I know that the leading arm (mid tire) will steer the coach.
-I know that true tracks keep (at least minimize) the bogie arm from steering the coach.
-I know that the bogie casting was designed for a certain load and to have certain characteristics at THAT LOAD. Changing that load will alter those characteristics. It has to. Cantilever a rod off a workbench and put a weight on the end. Measure the deflection (bend in the rod). Then double the weight. The deflection WILL increase SOME amount. In our case, at the very least, this will have some effect on how much the tire leans in at the top (camber). It may not be enough to matter. Or perhaps it may???
-I DON'T KNOW if adding X lbs to a coach will cause the bogie to self steer more.
-I THEORIZE that the LEADING bogie arm (mid wheel) without true tracks will self steer MORE with additional weight added to the coach over the design weight. I'm not talking about 1-200 lbs, I'm talking about 1000+ lbs. I don't think anyone knows what the Prince coach weighed???
-I also believe that True Tracks are one of the greatest things since sliced bread as it relates to the GMC. The handling of my 77 improved dramatically and I've heard many of you say the same thing.
Just a thought for discussion.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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