Over GVWR? Slow Down

[RustyJC]

Originally posted by Mike Ellis

Doh! I just *had* to go off and read about the blackout, if I had come back to TDR a bit quicker that $5 would have been mine

Mike,



Drag racing 101 - Them that snooze, lose!



Rusty

 

[jponder]

Originally posted by Mike Ellis

Doh! I just *had* to go off and read about the blackout, if I had come back to TDR a bit quicker that $5 would have been mine

Snooze you loose Baby! Plus you would have had to commit to the GP or the Hogs and it seems that maybe you are on the fence! Plus RustyJC has marked himself forever as a GP AND he owes me . 50 cents, I anint paying the extra postage to send him the 2 quarters. He is a marked Man forever

 

[Sticks]

You people frighten me. No offense, I have a great deal of respect for those that know and can do the math on things like this. I just know that I am way outta' my league.



I am just a simple, uneducated, newbie to this whole towing thing, and my only concerns with towing massive weights with a truck is:

1. Control of the vehicle.

2. Something breaking (I. E. hitch, axle, leaf spring, frame... ) at any speed over 5mph, or while I am in proximity to potential parts doing a sudden vector change.



I live my life by common sense, and a huge desire not to become a statistic.



I know that the engineers and the rule makers set the limits to everything well below the expected breaking point. I just choose not to find out what the actual breaking point is. If I have a weight limit of 12,500#, I know that I can safely push that about 20 - 25% past and still be safe. My brain makes the translation and the safety factor clicks in. I will have already gotten a feel for what I have before I get on the roads with the general public and will drive accordingly.



People can say "I haul 25000#'s with my truck every day" My response to that is "That little 2. 5"x 3. 5" pin or ball (1" at the narrowest point) is all that gets you from point 'A' to 'B', and you can't control anything other than that truck and trailer along that route. "



Now we can push this to "Sheer strength" and Physics. I know that that hardened tempered steel hitch has a frightening number of pound sheer strength, but that 25000# trailer is putting an exponentially frightening amount of force on a hard deceleration or turn just from the kinetic energy. Will it survive an instant 5 mph or 10* vector change from soccer mom that suddenly decided that she needed to turn right when she is in the left lane? Probably, but nothing else on on the truck will. And pitty the mini van or SUV.

 

[jponder]

People who stick with the suggested weight limits and then Haul A$$ frighten me. Do you agree that speed is MUCH more dangerous than weight? That is what this topic was about.



The whole gist of this was the question . Do you beleive a guy who is at 20K going 70MPH ( both withins the GCWR and posted speed limits) Is safer than someone who is at 30K and going 55 MPH( 10K over and going the speed limit). There are a group of people who say the first guy is fine and the second guy is not. There is another group that realize the first group doesnt have a clue. Our Manuals dont talk about speed and its the killer not the weight.



Please slow down and quite scaring us!

 

[Mike Ellis]

sticks,



Your points are quite valid, but note that your comments that you feel safe at 20 - 25% overloading put you solidly into the HOG group as far as the law or many of the GP's here are concerned. There is no hard data that says we are "safe" even at 5% over the GVWR. Of course there is no hard data that says we are "safe" at 5% UNDER the GVWR either, which is one reason the discussion is so subjective.



Truthfully, any time we hitch ANYTHING up to the back of our trucks and hit the highway, we are exposing ourselves and other drivers on the road to greater risk simply because a trailering rig cannot react as quickly / controllably to avoid an accident as an unloaded vehicle. We are individually willing to take this extra risk to accomplish our specific goals, but we take a lot for granted. There is no data provided with our trucks, for example, that shows they are "safe" to drive at 70 mph when trailering near CVWR. I imagine most people think the unloaded trucks are "safe" at 70, but it would be hard to argue that they are still "just as safe" at 70 when pulling a big honkin' trailer or with a couple of pallets of bricks in the bed.



Best way for all RVers to avoid problems is to simply slow down. Drive slower when loaded than when unloaded. If you are in an overload situation, drive still slower to compensate. And of course, follow the ancient wisdom of KYTOYA.

 

[jponder]

Originally posted by Mike Ellis

sticks,



Your points are quite valid, but note that your comments that you feel safe at 20 - 25% overloading put you solidly into the HOG group as far as the law or many of the GP's here are concerned. There is no hard data that says we are "safe" even at 5% over the GVWR. Of course there is no hard data that says we are "safe" at 5% UNDER the GVWR either, which is one reason the discussion is so subjective.



Truthfully, any time we hitch ANYTHING up to the back of our trucks and hit the highway, we are exposing ourselves and other drivers on the road to greater risk simply because a trailering rig cannot react as quickly / controllably to avoid an accident as an unloaded vehicle. We are individually willing to take this extra risk to accomplish our specific goals, but we take a lot for granted. There is no data provided with our trucks, for example, that shows they are "safe" to drive at 70 mph when trailering near CVWR. I imagine most people think the unloaded trucks are "safe" at 70, but it would be hard to argue that they are still "just as safe" at 70 when pulling a big honkin' trailer or with a couple of pallets of bricks in the bed.



Best way for all RVers to avoid problems is to simply slow down. Drive slower when loaded than when unloaded. If you are in an overload situation, drive still slower to compensate. And of course, follow the ancient wisdom of KYTOYA.

WHOAA now to get into the Hogs he must first state for the record that he is no longer skeered and pass a driving test. If he can drive a standard transmission for one solid day with absolutely NO brakes he will have seen the light and we will welcome him. To make the transition from GP to HOG the GP's must be forced to drive vehicles that have absolutely no brakes and then they will be cured. They will worry alot more about speed than weight.

 

[Fireman]

Two other things to consider

1 maintain extra distance between you and the vehicle ahead. Common sense, I know, but common sense isn't as common as you might think.



2 differential speed (and I'll let you engineer and physicists figure this one) If the speed limit is 70 and you are driving 55 and Joe Hotrod is comming up from behind at 80 how fast is he closing? Does he know that? This seems to be a major factor on US Interstates today.



Fireman

 

[Sticks]

Originally posted by jponder

WHOAA now to get into the Hogs he must first state for the record that he is no longer skeered and pass a driving test. If he can drive a standard transmission for one solid day with absolutely NO brakes he will have seen the light and we will welcome him. To make the transition from GP to HOG the GP's must be forced to drive vehicles that have absolutely no brakes and then they will be cured. They will worry alot more about speed than weight.

I, Sticks, officially state for the record that I can, prefer, and do (ETH/DEE) drive a manual transmission and know full well the limits of my ability and posses the skills to both utilize the gearing in the transmission to control acceleration and deceleration on steep roads and city traffic, and slow down/stop faster and safer than Billy Badd A$$ and Soccer Mom in their lifted and tweaked SUV's that think that just because they are a 4wd vehicle they can drive like they normally do on snow packed and iced roads.



I know the benefits to an exhaust brake, and am not afraid to use it at all times to assist slowing and stopping.



I know that when I have a load, my stopping distance has lengthened greatly, and my turning speed has been significantly reduced. I know that just because the speed limit is 75, it does not mean that I must be doing 75. Me, My truck and an overgrown breadbox of a camper attached to the rear at the max weight... 60 - 65 is fine on the open highway... 50 - 55 going through a city and keeping a decent distance between me and the next guy (almost an impossible task).



I know the secret to safe driving is knowing what the people around you are going to do before they do (27 years of motorcycle riding taught me that), and to always be looking ahead.



Like I said, I am just a simple, uneducated, newbie to this whole towing thing, I live my life by common sense, and a huge desire not to become a statistic. I don't know that I deserve to be classed in either of your groups. Respect for someone has to be earned, so I will just have to wait until we see each other on the roads.

 

[jponder]

Originally posted by sticks

I, Sticks, officially state for the record that I can, prefer, and do (ETH/DEE) drive a manual transmission and know full well the limits of my ability and posses the skills to both utilize the gearing in the transmission to control acceleration and deceleration on steep roads and city traffic, and slow down/stop faster and safer than Billy Badd A$$ and Soccer Mom in their lifted and tweaked SUV's that think that just because they are a 4wd vehicle they can drive like they normally do on snow packed and iced roads.



I know the benefits to an exhaust brake, and am not afraid to use it at all times to assist slowing and stopping.



I know that when I have a load, my stopping distance has lengthened greatly, and my turning speed has been significantly reduced. I know that just because the speed limit is 75, it does not mean that I must be doing 75. Me, My truck and an overgrown breadbox of a camper attached to the rear at the max weight... 60 - 65 is fine on the open highway... 50 - 55 going through a city and keeping a decent distance between me and the next guy (almost an impossible task).



I know the secret to safe driving is knowing what the people around you are going to do before they do (27 years of motorcycle riding taught me that), and to always be looking ahead.



Like I said, I am just a simple, uneducated, newbie to this whole towing thing, I live my life by common sense, and a huge desire not to become a statistic. I don't know that I deserve to be classed in either of your groups. Respect for someone has to be earned, so I will just have to wait until we see each other on the roads.

Welcome Hog Brother, if you ride a bike you already have eyes in the back of your head.



In the interest of safe parameters for the Hog Membership and realizing that we must come up with our own safe numbers for pulling I have decided to tentatively set the a Maximum Kinetic energy allowed(Suggested ) for the hogs.



Lets see since I dont want to use Joules or any of that we will need a new energy unit. It will be (Miles/Hour)squared times Lbs, I dont see the point in dividing it by 2 guys and gravity will fall out when you compare KE1 to KE2



It will be called HOG ENERGY and be HE. Since all of our calcs will be for comparison to some max HE ;Pounds will work okay. I dont want the engineers to get huffy about us using pounds.



Okay here is our two equations for energy comparison between us and Rocket Boys. Our initial Max energy will come from a typical GCWR AND the typical Interstate max speed. 20K @ 70 MPH 0kay ..... 70X70x20= 98,000,000 HEwhenever you are pulling you just multiply your weight times your speed squared and you will get your HE and you can say well yes I am heavy but I can stop faster than you! And they will just give you a blank stare



Since we have a max energy now you can calculate your speed with ANY weight config that would put you below the energy of 20K@70MPH=98,000,000 HE.



Lets check this to make sure it works

tHE FORMULA is V=sqrt(98000000/lbs) or if you take 98 million and divideit by your weight in lbs and then take the squareroot of it it will give you the equivalent speed where your energy would equal a 20K rig at 70 MPH. Now this will work either way if you use weights below 20K it will shw you a higher speed and weights above 20K will show you a lower speed. Even if you think all this is HOG WASH it still gives you a nice little equation to kinda check your self



I am going to some vedors to make us HOG Meters, we wont be using speedos anymore

 

[Mike Ellis]

Good job jponder,



I am picturing kids sweating in the driver's ed classroom years in the future, trying to remember acronyms during the test: "Okay, lessee here 'HE' ... that must be 'high explosive'. . nope, oh yeah HOG ENERGY!"



I vote that we term the official unit of HOG ENERGY the "ponder". This is a great choice because of course as you get loaded up heavier and heavier you have a "ponderous load"

 

[Barry]

Congrats to all! This is one of the most informative threads we have had in this forum... ... ... ... ... ... ... ... Thanx to all!

 

[Sticks]

Originally posted by Barry

Congrats to all! This is one of the most informative threads we have had in this forum... ... ... ... ... ... ... ... Thanx to all!

Informative hell, there should be a disclaimer posted at the beginning that states "Persons with less than 14 years of education, or education lacking in higher math and physics should view at their own risk, and should take appropriate doses of aspirin, ibuprofen, or other recommended pain relievers before continuing. "



I think I shorted something out reading the last math post, and am feeling the beginning of what is sure to be the mother of all migraines.





Ponder(HE)={M(V2)}

HE - Hog Energy

M=Mass/weight

V=Velocity/mph



jponder's equation!



I don't even want to try to figure the equation for the minimum distance allowed between your mass and the next mass in front of you.

 

[Barry]

... ... ... ... or how long does it take to get the upholstery out of your butt after you missed calculated... ... ... ... ... ... ... .

 

[zari]

Wow...

... you guys were busy throwing numbers around.



I agree, speed is <em>as important</em> a factor as weight in driving safely; and just because you square speed in the kinetic energy formula doesn't make it 'squared' as important .



And, y'all are forgetting about potential energy and (to a lesser extent) energy losses through heat, e. g. friction. Weight (or more precisely mass, if you'd like) does play a role , especially in mountainous terrain - after all your total energy is E_kinetik + E_potential - E_losses (this is the conserved entity. )



Actually, you'd have to include relativistic energy E_rel = mass x (speed of light)^2 as well (where mass is relativistic mass, i. e. (mass at zero velocity) x [1 - (speed)^2/(speed of light)^2]^(-1/2) ~ note that to be exact, this is the mass you'd have to use across the board for all "mass" instances), but at the slow speeds (no offense) that our trucks are moving, we can consider mass to be constant, so this energy will be cancelled out for all practical purposes.



Did I mention that I'm a physicist by education ?

 

[jponder]

Re: Wow...

Originally posted by zari

... you guys were busy throwing numbers around.



I agree, speed is <em>as important</em> a factor as weight in driving safely; and just because you square speed in the kinetic energy formula doesn't make it 'squared' as important .



And, y'all are forgetting about potential energy and (to a lesser extent) energy losses through heat, e. g. friction. Weight (or more precisely mass, if you'd like) does play a role , especially in mountainous terrain - after all your total energy is E_kinetik + E_potential - E_losses (this is the conserved entity. )



Actually, you'd have to include relativistic energy E_rel = mass x (speed of light)^2 as well (where mass is relativistic mass, i. e. (mass at zero velocity) x [1 - (speed)^2/(speed of light)^2]^(-1/2) ~ note that to be exact, this is the mass you'd have to use across the board for all "mass" instances), but at the slow speeds (no offense) that our trucks are moving, we can consider mass to be constant, so this energy will be cancelled out for all practical purposes.



Did I mention that I'm a physicist by education ?

Yes I have been dreading and waiting for Mgh to be mentioned, I sure would never mention it on my own and it really is going to be a problem for the HOGS in the mountains. Not to mention the problem of how to define it in HE's. I guess all I can say is I live in the southeast and I try to stay away from mountains. The other thing is You really need a good exhaust brake.



Lets look at the problem. If we assume a vacume and frictionless tires a vehicle starting from a stop would reach 396 Miles/hour with a 1 mile drop in altitude. It could be a 10% grade over 10 miles or push it off a 1 mile high cliff doesnt matter. We are talking BIG HOG ENERGY HERE!



The other thing that ZARI mentions hits hard on the HOGS is To get to the top of that hill we had to do much more work and we have stored all this energy by seperating ourselves from the center of the earth and NOW WE CANT USE IT. Our mileage is killed, which really upsets me. We could have a giant Inetial wheel and store the energy on the way down, or maybe some king of massive spring that we could use on our trip down to store energy qand slow usand then engage it to carry us up the next hill. One Day when we have the fuel cells we could engage a generator and produce Hydrogen on the way down and then burn it on the next hill going up. You know it would be similiar to butane that actually might could be done today



All we have to stop us our brakes and engine braking and its a dogone shame. We might as well be fred flinstone.



I geuss all I can say is HOGS have some real challenges in the mountains

 

[jponder]

I was bored at the office today and I had a thought. What would win? a new truck pushed of a 1/4 mile cliff or one of our faster drag trucks and the answer is... Assuming no wind resistance a truck pushed off a 1/4 mile high cliff would run a 12. 38 second 1/4 mile until it crossed... er slammed into the ground so it appears we have some truck that are faster than gravity.

 

[rweis]

Get yourself a very tall 5er to add your own built in wind brake to the equation.



Now how much wind brake does a tall 5er generate, and at what speed on what grade will it be in equilibrium down hill?



Great thread though, liked the above about some faster than gravity.



Bob Weis

 

[Blue2002]

Speaking of fueling the fire... ...



I wonder if anyone can tell me why a 3,000 gal Pierce Arrow Fire Engine might stop quicker when full than when empty? Could be a little more traction from the extra weight over the back wheels? Naw...



Also has anyone here ever used sandbags in the back of their truckbed when during the winter months?



Sometimes, within reason, a little extra weight can be good in the right places. ( Don't tell my wife I said that :{ )



... ... ... But I realize that there are a whole bunch of variables here and I won't being maxing out my Ram on weight while doing 80mph

 

[Mike Ellis]

zari,



It is true that in mountainous terrain the extra mass hurts you twice due to the PE term, but even considering potential energy, it can be safer to be heavy and go down the slope sedately than to be lighter and moving appreciably faster. Take two trucks at the top of a hill, going 50 mph and loaded equally. Overload one by 20% and keep him at 50 mph, leave the other one at original weight but speed him up by 20%. Total energy that must be braked away is still greater for the speeding truck, neglecting frictional losses etc. (At least it is if I fumbulated my calculator correctly) Why? Because the term for KE goes up with square of velocity, while PE is still linear. Gotta love that work-energy theorem, looking at the numbers will really grab your attention.



The way some of our RV guys drive, relativity may indeed be a player. I had 3 trucks pulling fivers pass me out in the Panhandle late one night, I am sure when they passed their lights were noticeably redshifted. (Or are all tail lights red? I can never remember )



Have to admit those guys blasting by me sure woke me up better than the caffeine... .



Mike

 

[Sticks]

Re: Wow...

What you said

Originally posted by zari

... you guys were busy throwing numbers around.



I agree, speed is <em>as important</em> a factor as weight in driving safely; and just because you square speed in the kinetic energy formula doesn't make it 'squared' as important .



And, y'all are forgetting about potential energy and (to a lesser extent) energy losses through heat, e. g. friction. Weight (or more precisely mass, if you'd like) does play a role , especially in mountainous terrain - after all your total energy is E_kinetik + E_potential - E_losses (this is the conserved entity. )



Actually, you'd have to include relativistic energy E_rel = mass x (speed of light)^2 as well (where mass is relativistic mass, i. e. (mass at zero velocity) x [1 - (speed)^2/(speed of light)^2]^(-1/2) ~ note that to be exact, this is the mass you'd have to use across the board for all "mass" instances), but at the slow speeds (no offense) that our trucks are moving, we can consider mass to be constant, so this energy will be cancelled out for all practical purposes.



Did I mention that I'm a physicist by education ?

What I heard



... you guys were busy throwing numbers around.



I agree, speed is <em>as important</em> a factor as weight in driving safely; and just because you square speed in the blaah blah energy formula doesn't make it 'blaah blah' as important .



And, y'all are forgetting about blaah blah energy and (to a lesser extent) energy losses through heat, e. g. friction. Weight (or more precisely mass, if you'd like) does play a role , especially in mountainous terrain - after all your total energy is blaah blah blaah blah (this is the conserved entity. )



Actually, you'd have to include blaah blah energy blaah blah (speed of light)^2 as well (where mass is blaah blah mass, i. e. blaah blah blaah blah x2 blaah blah blaah blah blaah blah blaah blah blaah blah blaah blah ~ note that to be exact, this is the mass you'd have to use across the board for all "blaah blah " instances), but at the slow speeds (no offense) that our trucks are moving, we can consider mass to be constant, so this blaah blah blaah blah blaah blah blaah blah blaah blah .





Did I mention that I'm a physicist by education ?



No offence meant zari. I am way outta' my league here.



Sorry guys, my head hurts. I am removing my subscription to this thread