โJan-27-2014 08:30 AM
โFeb-03-2014 10:18 AM
โFeb-03-2014 10:02 AM
โFeb-03-2014 06:04 AM
BenK wrote:I read your post a few times as I believe it was directed to me or at least people you think are like me. I'm not sure I understand your point. If I understand you correctly, people should never question existing technology or science. If people did not question why things are the way they are, technology would never improve or move forward. There are people in professions that operate within known parameters to produce items or goods and there are people within those professions looking for new cutting edge technology to make improvements or find new products. In keeping with the spirit of engineering related to rv towing, look at the recent WDH adjustment for front end rise. People questioned the way is has been done for years, engineers looked at it and the rules were changed. People accept the new changes, but it was the people and/or engineers that questioned the existing method to make the change. As far as designs that could use improvement, look at the Reese dual cam system (sorry to those of you that love it). This in my opinion is one of the worst designs ever. They want to fix a lobe in a stationary position and they use all moving parts to accomplish that. In my opinion, Equal-i-zer did better job with the L-bracket, but what were they thinking with that pin to hold the bar on the bracket. Also, why don't they suck it up, say you need to drill a hole in your A-frame so that the L-bracket can be bolted so it doesn't move. Even though each of these hitches have their problems, we use them because it is what is available.
Some very poor to dangerous advice on technology based questions or issues by
NON techie folks.
Most times the school of hard knocks did teach the advisors correctly or close
enough...but too often...way off base to argue against engineering principles
which are based on the world's "laws of physics" that we all live in
On designed in safety factor...there are many to anything as complex as automotive.
There are compounding that even some designers of 'that' part of the assembly
does NOT know of (from other components/assemblies within the whole)
Myopia and out of context is often too common here and other Internet freebie
forums
That is only part of 'why' you bounce back and forth between, as
it maybe or is between two different aspects that has their own dialed
in margins (safety factors and design spec)
I dropped out on my last straw thread...how tight should a tow ball
be tightened to. Simple and just a tow ball right?
Missed by the poor advice is that is a key component in the food chain
of towing
Advice from makes not matter...just use a pipe wrench...the designers
over design and that +400ft/lb torque spec is okay to ignor...gluing
on the nut...to just use a cotter pin to hold the nut without much
torque...
Pure danger to anyone who might listen and follow.
This thread is way above that 'torque on the tow ball' thread, as
that ball torque is just a component in the food chain of towing...but
it is a critical link of that food chain.
Again, technology to non technology savevy folks that argue the merits
of technically based advice
Ron has way more patience than I...as I've put this forum off for a
while and just cruise by occasionally...but had to comment on this one
He has put up with way more disingenuousness than I've been able to take
โFeb-03-2014 05:29 AM
xcntrk wrote:This was the point I was trying to make, this version is much better than mine.
So to the root of these last 4 posts; this utility is very simply based on the math and nothing more. It's a tool where a member of the towing community can hit the CAT scale, plug in their raw data against the corresponding manufacture specifications, and walk away with an understanding of where they fall in comparison. There is no 20% safety margin or subject of towing best practices involved in this tool. That responsibility falls to the user based on their level of comfort. For example this tool will tell you if you're at 99% of your GVWR, but does that mean it's a good idea to be at the bleeding edge of your vehicle limits? That's a question only the user can answer based on their comfort level....
โFeb-03-2014 05:27 AM
โFeb-01-2014 01:49 PM
Campin LI wrote:Regarding the underlined portion of your above post: You say all you meant was usually a factor of safety is used as in sometimes there is not one. What you actually said is found in the underlined portion of the post below.
Ron,
Please don't be astounded by anything I say. I'm just a guy who comes to the forum to get advice and I try to reciprocate from time to time by giving some. I meant no disrespect to you, sorry if you took it that way.
I am on the "other side" in construction. I do not have the technical background to analyze and design things but I am very interested in it and I believe I have the ability to follow along. Most of my knowledge is based on trial and error without the math analysis. That is probably why I bounce back and forth between variables within the same paragraph. I also don't have the desire to ponder over the perfect words so that they can't be twisted to mean something I did not intend to say. For instance above, all I meant was usually a factor of safety is used as in sometimes there is not one. I actually don't know what you twisted it into other than saying there is no such thing as usually when determining a factor of safety or something to that effect.
That being said, the only intent of my post was to make people aware that specific to RVing, the variables in the analysis can be under constant change, and nothing more.
My last paragraph was meant to be a joke. Sorry you didn't get it.
Campin LI wrote:
Thank you for taking the time to put this utility together. As long as the person reading through it can understand the math, it is a great way to learn what the weights are and what the effect of the weight has on the setup.
The only thing I would add is that it should be used as a learning tool, not as a tool to analyse a setup once to see if you are within limits. If you are concerned about limits, generally it means you are close to them. The reality is, every camping trip, the trailer is loaded differently based on location, duration and number of people. It is also loaded differently on the way to your destination vs the way home. Over the years, you accumulate more things in the trailer and it becomes heavier. Depending on the length of the trip, more or less items will be in the truck, the list goes on. As an example, my V10 Excursion has a 44 gallon fuel tank located behind the rear axle. Dependent on how much gas is in the tank, the dynamics change during the trip.
Usually when engineers design things or analyze them to this degree, there is a 33 1/3% factor of safety involved. That factor of safety usually covers things like uneven load, shifting weights, etc. I never see the factor of safety included in these analysis and that is why some people end up not being happy with their setups. The factor of safety was probably (I don't know for sure) included when the limits analyzed with the utility were set by the manufacturers, so I believe there is some wiggle room either way with respect to weight limits, but the same factor of safety should be used when analyzing your weights. I'm not saying a 1 ton dually is needed to tow a popup, but rest assured, when the owner says he doesn't know it's back there, he's telling the truth (even if it's swaying all over the place)
โFeb-01-2014 11:43 AM
Campin LI wrote:
Thank you for taking the time to put this utility together. As long as the person reading through it can understand the math, it is a great way to learn what the weights are and what the effect of the weight has on the setup.
The only thing I would add is that it should be used as a learning tool, not as a tool to analyse a setup once to see if you are within limits. If you are concerned about limits, generally it means you are close to them. The reality is, every camping trip, the trailer is loaded differently based on location, duration and number of people. It is also loaded differently on the way to your destination vs the way home. Over the years, you accumulate more things in the trailer and it becomes heavier. Depending on the length of the trip, more or less items will be in the truck, the list goes on. As an example, my V10 Excursion has a 44 gallon fuel tank located behind the rear axle. Dependent on how much gas is in the tank, the dynamics change during the trip.
Usually when engineers design things or analyze them to this degree, there is a 33 1/3% factor of safety involved. That factor of safety usually covers things like uneven load, shifting weights, etc. I never see the factor of safety included in these analysis and that is why some people end up not being happy with their setups. The factor of safety was probably (I don't know for sure) included when the limits analyzed with the utility were set by the manufacturers, so I believe there is some wiggle room either way with respect to weight limits, but the same factor of safety should be used when analyzing your weights. I'm not saying a 1 ton dually is needed to tow a popup, but rest assured, when the owner says he doesn't know it's back there, he's telling the truth (even if it's swaying all over the place):)
โFeb-01-2014 10:26 AM
โFeb-01-2014 10:16 AM
โFeb-01-2014 10:11 AM
xcntrk wrote:
So to the root of these last 4 posts; this utility is very simply based on the math and nothing more. It's a tool where a member of the towing community can hit the CAT scale, plug in their raw data against the corresponding manufacture specifications, and walk away with an understanding of where they fall in comparison. There is no 20% safety margin or subject of towing best practices involved in this tool. That responsibility falls to the user based on their level of comfort. For example this tool will tell you if you're at 99% of your GVWR, but does that mean it's a good idea to be at the bleeding edge of your vehicle limits? That's a question only the user can answer based on their comfort level....
โFeb-01-2014 09:48 AM
โFeb-01-2014 09:23 AM
Campin LI wrote:
Ron,
Please don't be astounded by anything I say. I'm just a guy who comes to the forum to get advice and I try to reciprocate from time to time by giving some. I meant no disrespect to you, sorry if you took it that way.
I am on the "other side" in construction. I do not have the technical background to analyze and design things but I am very interested in it and I believe I have the ability to follow along. Most of my knowledge is based on trial and error without the math analysis. That is probably why I bounce back and forth between variables within the same paragraph. I also don't have the desire to ponder over the perfect words so that they can't be twisted to mean something I did not intend to say. For instance above, all I meant was usually a factor of safety is used as in sometimes there is not one. I actually don't know what you twisted it into other than saying there is no such thing as usually when determining a factor of safety or something to that effect.
That being said, the only intent of my post was to make people aware that specific to RVing, the variables in the analysis can be under constant change, and nothing more.
My last paragraph was meant to be a joke. Sorry you didn't get it.
โFeb-01-2014 07:43 AM
โJan-31-2014 08:00 PM
Campin LI wrote:As a civil engineer whose working career was mainly devoted to research and development on the structural design and analysis of offshore drilling and production structures, I am astounded by this statement. When it comes to factors of safety, there is no such thing as "usually". I suggest you read this, which is highly generalized, but should give you some idea of how much variability there is in factors of safety.
Usually when engineers design things or analyze them to this degree, there is a 33 1/3% factor of safety involved.---
---I never see the factor of safety included in these analysis and that is why some people end up not being happy with their setups.---If a factor of safety were known, how would it prevent people from not being happy with their setups? If someone knew that a 1000#-rated WD bar would fail at a static load of 3000#, how would that keep them from being unhappy?
---The factor of safety was probably (I don't know for sure) included when the limits analyzed with the utility were set by the manufacturers, so I believe there is some wiggle room either way with respect to weight limits, but the same factor of safety should be used when analyzing your weights.---If a manufacturer's factor of safety were known, how would one use that FoS when analyzing weights? Can you give a specific example?
---I'm not saying a 1 ton dually is needed to tow a popup, but rest assured, when the owner says he doesn't know it's back there, he's telling the truth (even if it's swaying all over the place):)If a 1 ton dually is not needed to tow a popup -- then what is your point?
โJan-31-2014 06:18 AM