For the remodel I expected lil' yeti would weigh enough to warrant the heavier axle. And that everything in my truck would justify new air springs. The way to be sure of course was to weigh 'em. Easy, right? Just drive the truck onto a scale to get its weight. Then park the trailer on the scale for its weight. Two readings.
Too simple? I wanted to know more. How was my truck's weight distributed between the front and rear axles? How much camper weight was on its tongue versus axle? How much the hitch weight of the trailer changed my truck axle weights? How much margin remained? Does anything need to go on a diet? Lotsa questions.
So I visited a scale to get some weights. I figured in for a penny in for a pound. So $16 later I had 8 scale tickets and a math problem.
The data didn't make sense. Why would the front axle of my truck weigh 520 pounds MORE with the trailer hitched on the rear? Did lil' yeti really weigh 3,460 with 880 tongue weight? Color me skeptical. Extremely. Something smelled wrong. So I parked the problem. I believe in the power of the subconscious. Eventually it offered an explanation.
Context. The truck scale rounded off readings to the nearest multiple of 20 pounds. So I figured the margin of error should be in that ballpark. Through the magic of linear algebra. And several pages of math. Nothing difficult. Just lots of tedious addition, subtraction, multiplication and division. Anyway, I got some answers. Then made a spreadsheet to double check my calculations. Plus error analysis. The data was dirty alright. Yep +/- 248 was WAY too much measurement error.
What's the culprit? The morning I got the scale readings it was snowing in CO. Heavily. I was headed south, keen to cross two passes before wet roads froze that night. When I pulled onto the scale it was already covered in several inches of slush. I wondered if maybe the operator didn't zero the scale before my first weights with the trailer. But then reset it before my last readings with just the truck. Were my first weights contaminated by snow load? Another round of analysis seemed conclusive.
Reality check. Could snow really weigh 633 pounds? Here's a napkin estimate. Suppose there's a quart of partly frozen water per square foot over the whole surface of the scale which I'll guesstimate at 8 by 40 feet. That'd add up to 640 pounds. Plausible indeed.
The math was good exercise for my brain. Some cobwebs got blown out. And I got some answers. While neither axle of my truck was overloaded the combined total was high so it could loose some weight. But the camper's good. The tongue weighed 11% of the trailer total. And the axle was loaded to 85% of its capacity. Data gives me confidence. Clean data.
