24 replies to this topic

[EdoHart]

You sweat the wind hits you the sweat evaporates Bingo.

I've heard of that. I thought you were going to say it actually had an air conditioner out of an 80's era Buick, or something similar.

[pods8]

For whatever its worth (I've got a number of buddies in automitive engineering) and was chatting with a friend that was at ford for a number of years. He was saying the F150 was designed to haul a yard of top soil ~2000lb and that is what they designed for however ford throws a lower rating on there for a variety of reasons. Think about it if 2000lb = 5% premature failures for instance and 1500lb = 1%, then you can guess which number they'd put on it to avoid less potential repair work in the long term project numbers outweighed the sales boost they'd get for publishing a higher rating. Plus I'm sure there are all kinds of other issues our non-corporate driven minds wouldn't consider.

[Alaskan Snowbirds]

I don't have experience with mechanical/automotive design, but for structures, especially where loss of life could result if there is a failure (like bridges or buildings), it's normal to add a "factor of safety". How much of an overdesign is used depends a lot on how much/little variation is typical in the quality of materials being used, how likely an overload is, etc.

If the F-150 was designed for a ton and rated at 3/4 ton bed load then it sounds like about a 25% factor of safety was applied and that seems like it would be in the ballpark for a factor of safety.

On the other hand (why is there always an otherhand?) one of the reasons the factor of safety is put there is so that when we add all the stuff to the truck and camper and say "I think that's 1500#" and it's actually 2000# that we don't break our truck, or worse, (and blame the manufacturer for telling us it would haul more than it actually did.) So, it's probably best to use what the mfg. gives us for numbers.....I don't always do what's best.

Another 2 cents worth.

Happy Trails!
'birds

[pods8]

Yeah I'm aware of safety factors, I was getting the impression this was extra margin though. Anyways the manufacturer has their reasons for rating things one way and we as the user use that as guidance for our behaviours and consequences of them.

[Alaskan Snowbirds]

Pods8,

Might be because there are others out there like me that don't always do what they should!

Happy Trails!
'birds

P.S. Hope you're gettin' some high quality zzzzzzz's!