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RCMAN46

NorthWest

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Posted: 07/02/19 08:02pm Link  |  Quote  |  Print  |  Notify Moderator

Cummins12V98 wrote:



Let’s not forget 700# lighter and 50% less tire drag.


I would like to see the math you used to calculate the tire drag.

ksss

Eastern Idaho

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Posted: 07/02/19 08:57pm Link  |  Quote  |  Print  |  Notify Moderator

RCMAN46 wrote:

Cummins12V98 wrote:



Let’s not forget 700# lighter and 50% less tire drag.


I would like to see the math you used to calculate the tire drag.


Especially without having the drag coefficient of the asphalt. At least I assume he hasn't run a drag box across the Ike. But maybe...


2006 GMC 3500 CC 4X4 DRW D/A
2013 Fuzion 342
2011 RZR Desert Tan
2012 Sea Doo GTX 155
2018 Chevy 3500HD CC LB SRW 4X4 D/A
2015 Chevy Camaro ZL1

Groover

Pulaski, TN

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Posted: 07/02/19 10:22pm Link  |  Quote  |  Print  |  Notify Moderator

I was just looking at the 2019 Ford towing guide and thought that it is interesting that the F450 is listed as being the lowest and the duallys are lower than the single rear wheel versions:

Model F-150 F-250 F-350 SRW F-350 DRW F-450 DRW
Max. Tailgate Height** 58.3 inches 59.8 inches 59.6 inches 58.7 inches 58.0 inches

**Distance from ground to top of closed tailgate.

4x4ord

Alberta

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Posted: 07/03/19 02:14am Link  |  Quote  |  Print  |  Notify Moderator

Huntindog wrote:

Groover wrote:

Cummins12V98 wrote:

Grit dog wrote:

Cummins12V98 wrote:

Gooseneck hitch behind rear axle centerline. How stupid.


Yeah it must be waaaay back there to only be rated to tow 35k!

Lofl. Some people would bitsch and complain if you hit em upside the head with a bag of money...
.

Industry standard has been in front of axle for ever. Dumb to unload front axle.


The effect of loading/unloading the front axle varies with how far you are from the axle. We are talking 3 or 4 inches here vs maybe 50 or more with a bumper pull and most new trucks are rated to carry some astonishing weights on the bumper. You probably won't notice the small change here. However, with the trend towards short bed pickups smacking the back of the cab has become a real issue. A few inches backwards will make a huge difference on that. I hope that doesn't sound too much like a certain politician.
I think the video said it was 2"



The video did say two inches behind the center of the rear axle. It also said 3000 lbs of pin weight unloaded 100 lbs off the front axle. That doesn't add up. If 3000lbs of pin weight lightened the front axle by 100 lbs the pin would have to be positioned 5.3 inches behind the rear axle on a short box crew cab and even further back on a long box crew cab.


2017 F350 SRW Platinum short box 4x4.
B&W Companion
2008 Citation Platinum XL 34.5

Huntindog

Phoenix AZ

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Posted: 07/03/19 03:13am Link  |  Quote  |  Print  |  Notify Moderator

4x4ord wrote:

Huntindog wrote:

Groover wrote:

Cummins12V98 wrote:

Grit dog wrote:

Cummins12V98 wrote:

Gooseneck hitch behind rear axle centerline. How stupid.


Yeah it must be waaaay back there to only be rated to tow 35k!

Lofl. Some people would bitsch and complain if you hit em upside the head with a bag of money...
.

Industry standard has been in front of axle for ever. Dumb to unload front axle.


The effect of loading/unloading the front axle varies with how far you are from the axle. We are talking 3 or 4 inches here vs maybe 50 or more with a bumper pull and most new trucks are rated to carry some astonishing weights on the bumper. You probably won't notice the small change here. However, with the trend towards short bed pickups smacking the back of the cab has become a real issue. A few inches backwards will make a huge difference on that. I hope that doesn't sound too much like a certain politician.
I think the video said it was 2"



The video did say two inches behind the center of the rear axle. It also said 3000 lbs of pin weight unloaded 100 lbs off the front axle. That doesn't add up. If 3000lbs of pin weight lightened the front axle by 100 lbs the pin would have to be positioned 5.3 inches behind the rear axle on a short box crew cab and even further back on a long box crew cab.
The video had a cutaway frame showing this.
It looked to me to be pretty close to 2".

Definantly NOT 5"



Huntindog
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2011 Silverado CC DA big dually.



4x4ord

Alberta

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Posted: 07/03/19 04:24am Link  |  Quote  |  Print  |  Notify Moderator

Huntindog wrote:

The video had a cutaway frame showing this.
It looked to me to be pretty close to 2".

Definantly NOT 5"


It could very well be that the hitch is only mounted 2 inches behind the rear axle..... in which case 3000 lbs placed on the hitch would take 38 lbs off the front axle. (On a CC short box)

Huntindog

Phoenix AZ

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Posted: 07/03/19 04:25am Link  |  Quote  |  Print  |  Notify Moderator

4x4ord wrote:

Huntindog wrote:

Groover wrote:

Cummins12V98 wrote:

Grit dog wrote:

Cummins12V98 wrote:

Gooseneck hitch behind rear axle centerline. How stupid.


Yeah it must be waaaay back there to only be rated to tow 35k!

Lofl. Some people would bitsch and complain if you hit em upside the head with a bag of money...
.

Industry standard has been in front of axle for ever. Dumb to unload front axle.


The effect of loading/unloading the front axle varies with how far you are from the axle. We are talking 3 or 4 inches here vs maybe 50 or more with a bumper pull and most new trucks are rated to carry some astonishing weights on the bumper. You probably won't notice the small change here. However, with the trend towards short bed pickups smacking the back of the cab has become a real issue. A few inches backwards will make a huge difference on that. I hope that doesn't sound too much like a certain politician.
I think the video said it was 2"



The video did say two inches behind the center of the rear axle. It also said 3000 lbs of pin weight unloaded 100 lbs off the front axle. That doesn't add up. If 3000lbs of pin weight lightened the front axle by 100 lbs the pin would have to be positioned 5.3 inches behind the rear axle on a short box crew cab and even further back on a long box crew cab.
I think a few things are screwing up your calculations.

Thae axle is NOT bolted to the frame.
It is bolted to the springs which are bolted to the hangers which are bolted to the frame. So the spring hager locations are where the frame "sees" the weight.
The video actually touches on this.
In addition:
The axle MAY not be centered on the leaf spring.
AND just to muddy the water a little more, the springs lengthen and shorten as weight is added/removed... So the axle will move for and aft a bit.


4x4ord

Alberta

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Posted: 07/03/19 05:59am Link  |  Quote  |  Print  |  Notify Moderator

The fulcrum is where the tire meets the road. It makes no difference where the springs bolt to the frame. If the axle moves relative to the hitch while it is loaded then the distance from the pin to axle as well as the wheel base will change slightly. So to be 100% accurate the measurements would be taken with the load on the pin. Loading the truck isn't going to change these dimensions a whole lot. For instance I'm certain the axle is not going to move forward relative to the frame three and a half inches when the springs are loaded, which is what would be necessary for the load to lift 100 lbs off the front axle.

ib516

Canada - soon to be Costa Rica

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Posted: 07/03/19 06:08am Link  |  Quote  |  Print  |  Notify Moderator

Huntindog wrote:


I was told by a long time GM engineer years ago, that when they tried 4.10s behind the D/A that the pinion would not hold up.

That may be why the AAM went from 11.5" to 11.8" to 12" over recent years.


Prev: 2010 Cougar 322QBS (junk)
02 Dodge 2500 4x4 5.9L CTD 3.55
07 Dodge 3500 4x4 SRW Mega 5.9L CTD 3.73
14 Ram 2500 4x4 Crew 6.4L Hemi 4.10
06 Chevy 1500 4x4 E-Cab 3.73 5.3L
All above are sold
Current: 07 Dodge 1500 5.7L Hemi 3.55 / 2010 Jayco 17z


ShinerBock

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Posted: 07/03/19 06:34am Link  |  Quote  |  Print  |  Notify Moderator

Cummins12V98 wrote:

ShinerBock wrote:

Cummins12V98 wrote:


Have I criticized GM because they would not admit the strength of their 6 speed was not op to the task and gave a LAME excuse of why their DRW could only pull 23,700#? HE!! yea!


And you will not admit that the Aisin is a slow and clunky transmission even though multiple review sites and people in the forums has stated this so what's the difference?

I would rather take a 6-speed Allison over an Aisin. Big whoop that it is only rated to tow up to 23k. Most people here, myself included, will never tow close to that much and would probably rather have a better shifting transmission with better shift points rated to tow up to 23k over a slow and clunky trans rated to tow 30k.


How bout this. Come drive mine at 10k solo and then at 35k double towing. Then tell me what you think.

What trans do you have? Oh yea NOT AN AISIN.


Why? I don't tow that much and neither does 99.9% of the people here so why would I choose a slower and clunkier transmission rated to tow 35k when a quicker, smoother, and better shift logic transmission is rated for well over what I and most people tow.

That is like buying a rough riding and slow Peterbilt 325 to tow a 20k trailer when a smoother, faster, and more comfortable 350/3500 pickup truck will do. I can't speak for you, but I for one don't need anything I have rated to tow some amount that I will never tow to compensate for other deficiencies. I also don't believe that everything is the best at everything with no flaws just because I own it.

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