Suspension help

mkirsch wrote:
Just like a tire, adding weight does not increase the pressure in the bags. The bags simply change shape. They bulge out as the suspension is compressed. He is overinflating them in the first place.

Airbags are there to LEVEL the truck, not return it to empty ride height when loaded. Ideally the truck should ride level when loaded on the overload springs.

Dry pin weight is 3225lbs on the 2014 RW415. Even if loading it added 2000lbs to the pin weight you should be well within the payload capacity of a 2013 DRW Chevy.

X-whatever on these two points:

1. That's what the overloads are there for.
2. How much pressure are you putting in the bags?

I always enjoy reading your posts and normally agree with you. But I'm reluctant to believe tire and/or airbag pressures don't increase with added load. I do agree that a pressure increase is often not easily noticable, but it should still be there. If the pressure did not increase with load somewhere along the line, tires and bags would never blow out... they would merely stretch indefinately as you say.

I think it more likely that the pressure only seems to normally stay the same as long as the "rubber" evenly stretches in linear fashion. When the stretch-distortion exceeds a certain elastic design limit (plys), the rubber tears. So extraordinarily compressed air suspension bags will eventually blow out from extreme self-pressure-increase, just as tires will if one just keeps adding weight to a tire already at max recommended pressure. For example this becomes apparent when one might imagine a ridiculous tire overload until the tread face nears (flattens to) the height of the bead on the rim.

Therefore it would be an interesting experiment to closely monitor precise rear tire pressure as one lowers the pin weight onto the truck. I think it should gain at least 1/2 pound or more as a rough guesstimate. The rest of the "squashed" volume should be taken up by innate "stretch-bulge design", maintaining very close to original pressure as you surmised.

For instance, if one were to alternatively lower such increasing weight on a bicyle pump handle, the internal air pressure increase at the pump outlet should entirely appear quazi directly proportional to the added weight because there is little to no stretch in the cylinder walls. Somewhere between a steel pump cylinder and large donut shaped tire, I think the range of small air bags (and small tires) are probably more susceptable to overload pressure blowout due to insufficient, stretchable square wall area.

Wes
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