Trailer Weight Calculations & Load Estimator Utility

[xcntrk]

Hi all, I've lurked on here for a while and have just now got around to creating an account.

I tow a number of different trailers regularly and I'm in the process of shopping for a new TT. As a result I've been researching & measuring all the specific manufacture ratings and real word scale weights surrounding my TV in order to help me identify trailer loads I can realistically support without being overloaded. To help in that process I built the following utility and wanted to share it with the rest of the towing community.


Weight Calculation utility:
Input your CAT or other truck scale measurement data and the utility will perform a number of meaningful weight calculations. This information is useful in measuring the "real" weights of your tow vehicle and trailer against the maximum limits of both vehicles. The tool will identify if you are over the manufactured specifications in any area and bring this to your attention.

Load Estimator utility:
Allows you to input information about a given trailer and estimate the amount of load required from the tow vehicle to support the trailer weight. Loads are projected in Tow Rating and Payload figures. Useful for trailer shopping to quickly determine if a prospective trailer fits your tow vehicle capabilities.

The tool is based in Microsoft Excel, but no need for any software on your computer as you can access the utility online via Microsoft Skydrive. You can input your data online and even download a copy for offline use (assuming you have Excel installed locally).


Here are a few screen shots of the utility in action:










Access the Trailer Weight Calculations & Load Estimator Utility here:
https://skydrive.live.com/embed?cid=A7EE35AF86FE78FE&resid=A7EE35AF86FE78FE%21142&authkey=ALI_KLtWUH...

EDIT: updated to version 4.0 to include corrections from comments originating in this thread.
PS: please contact me with any uncovered bugs or issues.

[DieterDedekind]

Thank you for this great tool. I am having difficulty figuring out how to in download the excel file. Can you please help?

[way2roll]

You are responding to a post that's 10 years old.

[DieterDedekind]

Wow, so helpful. All good though, I figured out how.

[opnspaces]

So how do you download? I looked at it and can't see how.

[DieterDedekind]

Use this link, will only work if you have a micrsoft account though.
https://skydrive.live.com/embed?cid=A7EE35AF86FE78FE&resid=A7EE35AF86FE78FE%21142&authkey=ALI_KLtWUH...

[opnspaces]

Interesting, it worked off your link but with a twist. Here's what I did in case it helps anyone else.

I clicked on your link and it opened a blank page with just the words Weight Calc... in the top left corner. 

link 

I click on the words Weight Calc... and it opened the excel sheet.
Then I clicked on File -- Create a copy -- download.

[BenK]

xcntrk wrote:

Seattle Lion wrote:
I can't think of anything that would be gained by decomposing the sources of the various limits on our TV's. The manufacturers have an incentive to make these ratings as high as possible, since truck purchasers are looking for the best payload and tow capacities. I worry that the margins of error may be made too small in order to accommodate the marketing department.

I don't agree with what you're saying here. Sure I get manufactures are free to establish their own benchmark for tow ratings, and therefore free to inflate numbers as they desire.

Disagree...

Back to my earlier posts on this...decide either you believe in the
OEM's ratings or not. Also note that GCWR has an 'R' in there

If no, then do whatever, but know that you have taken the OEMs (yes
more than one) off the hook and taken that liability

If yes, then learn how that system works and goes to that picture posted
earlier

Both liability and warranty are baked into all ratings

Hopefully this will soon change starting in 2015 as Toyota, Ford, GM, and Chrysler begin aligning with the SAE International Standard J2807 (Performance Requirements for Determining Tow-Vehicle Gross Combination Weight Rating and Trailer Weight Rating).

But to your point above, deciphering your axle or total vehicle gross weight rating is very much a combination of the underlying component parts that make up that rating, with the lowest common denominator limiting the rating. Take my little 1/2 ton pickup for example:

• Rear Axle unit w/E-locker and 3.73 = 4800#
  
• Rear Springs = 4050#
  
• Rear wheels (20" 6-lug) = 4050# (2025ea)
  
• Rear Tires 275/55R20 (P-scorpion) = 4806# (2403ea)

The axle housing itself can support up to 4800# gross weight however the limiting components are the springs and wheels which hold back the rear GAWR to 4050# as a result.

Over analysis to lose the over all picture....a rat hole and need to
go back up to 60,000 feet to see the system

We will NEVER know which is the weak link dictating these ratings.
All we can do is guess

On that, a weak link can be a shorter MTBF that the EOM lowers to gain
more 'RATING'. They knowingly do that all the time and for folks out
here think pulled out of the sky...

My rear GAWR is 6,000 and is the OEM rating (GM), but GM purchases this
from AAM.

AAM rates this assembly they ship to GM at 10,000 GAWR.

Some see that the OEM tires are approx 3,000 rated each...so they assume
that is the limiting factor...maybe...maybe not...again we'll never
know

that kind of thinking would have them go out and purchase 5,000 lb
rated tires...but wait...how about the wheels? How about the brakes?
How about the springs? How about the bolts for those springs? How
about the frame hanger? How about the frame itself? and a BIG ETC...

Again, decide if you believe in the OEMs ratings or not...then the
liability issues when you re-engineer. Yes it is a multiple faceted
'SYSTEM' comprised of many systems and components

[BenK]

BarneyS wrote:
Welcome back Ben! 🙂
Barney

Hi Barney,

Well just cruising here every once in a while....

Thanks!

[xcntrk]

Seattle Lion wrote:
I can't think of anything that would be gained by decomposing the sources of the various limits on our TV's. The manufacturers have an incentive to make these ratings as high as possible, since truck purchasers are looking for the best payload and tow capacities. I worry that the margins of error may be made too small in order to accommodate the marketing department.

I don't agree with what you're saying here. Sure I get manufactures are free to establish their own benchmark for tow ratings, and therefore free to inflate numbers as they desire. Hopefully this will soon change starting in 2015 as Toyota, Ford, GM, and Chrysler begin aligning with the SAE International Standard J2807 (Performance Requirements for Determining Tow-Vehicle Gross Combination Weight Rating and Trailer Weight Rating).

But to your point above, deciphering your axle or total vehicle gross weight rating is very much a combination of the underlying component parts that make up that rating, with the lowest common denominator limiting the rating. Take my little 1/2 ton pickup for example:

• Rear Axle unit w/E-locker and 3.73 = 4800#
  
• Rear Springs = 4050#
  
• Rear wheels (20" 6-lug) = 4050# (2025ea)
  
• Rear Tires 275/55R20 (P-scorpion) = 4806# (2403ea)

The axle housing itself can support up to 4800# gross weight however the limiting components are the springs and wheels which hold back the rear GAWR to 4050# as a result.

[Seattle_Lion]

I wasn't going to chime in, but there seem to be some misunderstanding of exactly what a safety margin is or isn't and how it might apply to us.

First of all, when limits or ratings are set for a TV, according to a Ford engineer who was interviewed on a car design (not truck but it still applies) was asked why top speed is limited for that vehicle. His answer was that above the limited speed, the probability of component failure in several areas was too high to be acceptable. What constitutes "too high" is, of course, not shared.

The point is that a TV is a complex system. That system has limits across multiple subsystems. The frame may be able to handle 5 times the MGVWR, but the springs can't. (Just examples, not facts). I can't think of anything that would be gained by decomposing the sources of the various limits on our TV's. The manufacturers have an incentive to make these ratings as high as possible, since truck purchasers are looking for the best payload and tow capacities. I worry that the margins of error may be made too small in order to accommodate the marketing department.

One thing I have learned from all these discussions is that many of us look for reasons to feel comfortable with pushing various TV limits. I can understand that. Trucks are very expensive and the thought of replacing that expensive item with an even more expensive one to support towing a TT or 5er is concerning.

[ependydad]

Frosty, I wrote this page/article exactly for folks in your position:
http://www.learntorv.com/p/what-can-i-tow.html

See if it helps. If you have questions, feel free to PM me!

[frosty1_4me]

Ok, I'm freaking confused about all of this. I'm new to trailer shopping. I have had nothing but a motor home before. I'm about to purchase a new/used trailer and I'm trying to figure out if my truck will have a problem towing it. (of course the salesperson says no problem).

I have a 2002 GMC sierra 1500 4x2 extended cab 6.5" box. It has a 5.3L, with a 3.73 ratio anti-slip rear-end with auxiliary transmission cooler and ride control. (rated 8100lbs towing)

Now, the trailer is a 2010 tracer 3000bhd RT. Dry weight 6082lbs, cargo of 1607lbs for max of 7727lbs.

According to the calculated posted in this thread, based on the estimates of cargo in the truck, passengers, etc. The calculated came back with a trailer range of 7400 to 11000lb trailer. Obviously it would be closer to the bottom end.

Can someone tell me if I'm going to have issue pulling this trailer? I talked to a parts guy at a dealership and he said it's on the bubble. I don't want to tax my truck so I don't have to worry about stranding my family by the side of the road.

Any info would be appreciated.

Thanks.

[JIMNLIN]

I'm going back to the trips, locations, destinations (or whatever they call it) forum. Good luck

Don't stay away as we need more folks like you willing to express common sense ideas instead of the same old humdrum ideas that never change or accept others opinions.

This from another RV website.
"Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts."

Some folks think their way is the only way and some even go out of their way to discredit others opinions.

[BarneyS]

Welcome back Ben! 🙂
Barney