Towing a TT with an old half ton truck questions

Good morning!

I am in the classic predicament of putting the cart before the horse but I'm ready to get out and do some RV camping ASAP!  Travel Trailer is 5500 empty and 505 tongue.  Brakes on both axles.  I'll be pulling it with my current truck for now with keeping my trips under 90 mile radius from home and packing very light knowing I'm at the limits of my tow vehicle.  I have access to an 8.1 Suburban and two older 5.9L Cummins Dodge trucks I can borrow from relatives if I decide to take a longer trip.  I'll do this for one year or less in which time I will replace my current tow vehicle with a used 2014-2016 half ton truck but that will be another thread .

I know the dry weight is usually pretty worthless but I will be making a conscious effort to travel lightly.  Like nothing in the trailer besides a few camping chairs, paper wear, and bedding.  All tanks will be empty and Ill use the state park facilities for shower and restrooms for now.  Only have one passenger and likely an ice chest in the truck.  I'm even thinking about removing all the contents of the outdoor kitchen to further reduce weight.

I have researched the numbers quite a bit but still have a few questions maybe someone can help with.  First my tow vehicle:

1991 Chevrolet C1500 Silverado (2WD) 141.5" WB Extended cab short bed
5.7L L31 Vortec transplant (new GM Goodwrench engine) +60 HP/+45 Tq over original 5.7L engine
NV3500 Manual Transmission 5 speed (refreshed recently and new clutch, slave, master, hyd lines)
3.42 gears
Z82 trailering package which includes KC4 engine oil cooler
31x10.5x15" Load Range C tires on stock steel rims

Max Tow Rating 6500 (Would be 7500 if equipped with 3.73 gears but I have yet to find a 2WD truck in these years with those gears outside a 1990 454 SS)
GVW 6200
Actual Weight of truck with driver 4500 lbs.
Max Tongue weight 850

The door sticker is faded beyond recognition so all of these numbers are coming from the 1991 factory brochure tailored as best as possible to my truck's equipment/configuration. 

What I cant figure out is the GCWR.  Is this simply as easy as adding the 6200 GWR of the truck + the 6500 max trailer weight rating?

Also, a question about payload.  Most of what I read here seems to indicate that older half ton trucks are far less capable in all areas than the more recent ones.  However when it comes to payload, the sales brochure lists the payload for a C1500 extended cab short bed such as mine at 2315 pounds but has an asterisk saying with standard engine which I assume to be the 4.3L V6 even on an ext cab.  However, if I take the 6200GVW rating of my truck and subtract the 4500 lbs (scale verified with me in the truck, full tank of fuel + personal effects) that gives me a 1700 lb payload and that is with me the driver in the truck!  Did I calculate that wrong?  Looking at the sales brochure it looks like the payload ratings of even the extended cab GM trucks in 1991 rival that of a late model Silverados and in some cases is actually better.

The GCWR is basically curb wight  + max tow capacity.  NOT GVWR + tow.  In other words, you only get the max tow capability with an empty truck. Every pound of of options, passengers and gear added to the truck itself gets subtracted from the Max Tow.
You calculated a real payload value. It's valid as long as the tires support the resulting rear axle load. I hope when you scaled it you got individual axle weights.

Thank you so much for the good information.  I did not think to get individual axle weights.  That was actually the question I forgot to ask.  Being that I don't have a door sticker, I could not find the Gross Rear Axle Weight Rating for my truck.  Is there a way to figure that out?  I can go back to the scale and weigh the axles but what does that information tell you?

I'm in the same boat as you with my silverado.  A few years back I was contemplating getting a TT to replace my popup camper with.  Once I looked at how the rating was affected by the highway differential I was bummed.  having the factory tow package doesn't really mean a whole lot like I thought it did just intuitively....

my 2 cents.... I wouldn't be looking at a brochure.
Seems like you have a great handle hold re. your truck's equipment and specs.  Take that info to the owners manual.  There would be charts in there for each combination of specific engine, tranny, diff ratio, etc...

also when I wrap my head around this stuff, right or wrong....but I ignore "max tow", payload, etc...

the numbers I look at
rating of each axle...drive and steer
the GVWR
the GCVWR
and the actual axle weights as measured

then, I would consider the tongue weight as added to the rear axle for estimating purposes...but better once you can actually weigh things hitched and unhitched to see the real result to both truck axles

then are any of those numbers over the rating?...
steer axle rating
drive axle rating
gvwr (total for truck + added tongue weight)
GCVWR total of everything hitched up

Personally, I don't put absolute stock in these numbers.  even with a brand new truck, when you get close but still under the ratings performance really suffers...  first hand experience
There are safety factors built in to them so I figure it's plenty "safe"....probably even if over a bit.... but I have certainly not felt completely safe towing things that are within spec with brand new trucks

and I've also towed many times local trips as a teen and young adult that now I understand were very likely severely overloaded.  Successful tows, driving carefully and gingerly, etc...  certainly felt safe enough to me at the time though...  sometimes a bit stressful maybe, but also sometimes really "ok"

now with age and hopefully wisdom, I'd be angry at that kid-me doing what I was doing towing like that on the same road as the me-now in my car with my family

http://www.rvforum.net/joomla/index.php/26-towing-and-towables/187-calculate-trailer-towing-capacity

This is the connection to Library example of towing calculations....
I used it and substituted my own truck and trailer numbers and feel confident on my "OLD TRUCK" and "NEW TRAILER" combination.

re your post while I was typing....
I wonder if you could search for it under you VIN?  Or maybe the dealership could look up the ratings?
OR....Are the axle ratings listed in the manual?  I can't remember....

The axle weights gives you something to compare to the tire max load data (on the tire sidewall).  If you assume the entire payload falls on the rear axle (which is close to true), you can verify that your calculated payload is actually usable.  Info on the axle GAWRs can be found from a Chevy dealer or online sources, but it's probably ok.
Can you also get the trailer weighed?  The brochure weights aren't very accurate, especially on older models or brands that offer stripped down base models with numerous options. That 5500 dry weight may be fiction. The 505  tongue weight almost surely irrelevant, because even a few extra pounds in the trailer typically changes it dramatically.  Plus a battery and propane on the trailer tongue.  By the way, as soon as you put water in the system the first time, you gain 75-100 lbs due to residual water in heater, water lines, the bottoms of the tanks, etc.
There's only so much you can do by calculation based on brochure numbers.

I will check the manual to see what it says.  The other problem besides the fact that my door sticker is no longer readable is the fact that my truck came out of the factory with the 5.0L (305) 170 HP engine, 5 speed with 3.08 gears (Yeah, I know, worthless, I called it the gulf states edition cause that combo was only good for cruising on flat land with zero load!)

Now I'm running the 1996-2000 vintage Vortec 5.7L, same trans and 3.42 gears.  I'll take it to the scales.

9c1fanatic said:

Being that I don't have a door sticker, I could not find the Gross Rear Axle Weight Rating for my truck.  Is there a way to figure that out?

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The GAWR won't exceed the tire weight ratings, so if you're running stock tires their max weight x 2 should get you in the ballpark.

Or crawl under the truck and look for the axle part number on a tag near the differential, then look up the part number on line.

I'm running LT tires which I'm thinking are a bit stouter than the original equipment tires which were p tires.  ill check for an axle tag.  Thanks!

I will weigh the trailer also.

Welcome to the Forum!

Your initial post and weights are correct.  Your payload is 1700#, and already includes you.  The yellow placard we talk about is NOT on your vehicle.  They did not appear before 2004, and were not required until 2009.  Besides, your calculation is more accurate!

I'm confident you are OK, but check the Load Rating on your tires.  It should be well above 1550# ( 6200 GVWR / 4)

You have a substantial payload for a small TT.  Assuming 700# for a passenger and cargo leaves 1000# for a hitch and tongue wt.  Even loaded to 7000#, the tongue wt will be in the 700 - 900 lb range.

Make SURE the tongue wt is AT LEAST 10% of actual trailer wt.  Any less and you will have trailer sway.

Keep asking questions.  You are on the right track!

Thanks so much for the info.

I checked my tires.  They are Michelin LTX 31x10.5 x15 LOAD RANGE C with a 2270 lb rating per tire at maximum PSI (50 PSI).  So think I'm good on the tires.

The tounge weight is my biggest concern.  It seems the advertised weights from the TT manufacturer are false according to many here so what is the best way to get the weight right?  I cant see dragging my rig across a public scale, then going over it again multiple times as I keep moving things around in the trailer to get the optimum.  Is there any kind of scale one can buy for this to use at home that you can put under the tounge jack with the jack set to the same height as it would be if it were connected to the truck? 

Also, when using a WD hitch, is there a certain amount of lbs that need to be factored in as being removed from the tongue weight?  I know the WD adds some weight but I also thought they removed some of the weight from the tongue?  I've towed many times and all kinds of trailers, but never a TT and never with a WD hitch so this part is new to me.

9c1fanatic said:

Is there any kind of scale one can buy for this to use at home that you can put under the tounge jack with the jack set to the same height as it would be if it were connected to the truck? 

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Here's a useful article showing a couple of different ways to determine the tongue weight.

https://www.etrailer.com/faq-how-to-determine-trailer-tongue-weight.aspx

The scales mentioned are available from Amazon, if you choose the bathroom scale method I'd follow the example in this YouTube video for a greater range:

https://m.youtube.com/watch?v=nMoLA44lcgU

9c1fanatic said:

Also, when using a WD hitch, is there a certain amount of lbs that need to be factored in as being removed from the tongue weight?  I know the WD adds some weight but I also thought they removed some of the weight from the tongue?  I've towed many times and all kinds of trailers, but never a TT and never with a WD hitch so this part is new to me.

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All a weight distributing hitch does is create a bridge across the hitch ball to force the front end of the truck down to the original ride height.  Without it the truck's rear axle acts as a fulcrum and as you add weight on the hitch the front of the truck rises and removes weight from the steering axle.

As the equalizing bars force the truck's front end downward, the front springs compress properly and transfer the correct weight to the steering tires.  It does not change the trailer's tongue weight.

Tongue weight is another way of expressing the location of the trailer's Center Of Gravity.  If you have weight on the hitch the trailer's CoG is ahead of the trailer's axles and it will be a stable tow.  You need enough tongue weight to keep the CoG forward of the axles when things like wind resistance on the front of the trailer and bumps, etc. try to push it rearward.  Letting the CoG get behind the axles is what causes sway to self-amplify.

All a weight distributing hitch does is create a bridge across the hitch ball to force the front end of the truck down to the original ride height.  Without it the truck's rear axle acts as a fulcrum and as you add weight on the hitch the front of the truck rises and removes weight from the steering axle.

Has anyone every hooked up their TT, placed the front wheels on a scale, and then weighed the front axle with and without the the weight distribution portion engaged?  I always wanted to do that but never did.  I would like to know a quantitative percentage of improvement that is obtained from a weight distribution system. Maybe someday i will get around to it.

Thank you all who replied.  The information and experience here is priceless.  I'm installing the brake controller on the truck this weekend.  Ill be headed to the dealership to negotiate on the price of the TT in 1-2 weeks.  If we can work a reasonable deal, Ill be the owner of Grand Design 2400BH! 

Thanks again!!

Lowell said:

All a weight distributing hitch does is create a bridge across the hitch ball to force the front end of the truck down to the original ride height.  Without it the truck's rear axle acts as a fulcrum and as you add weight on the hitch the front of the truck rises and removes weight from the steering axle.

Has anyone every hooked up their TT, placed the front wheels on a scale, and then weighed the front axle with and without the the weight distribution portion engaged?  I always wanted to do that but never did.  I would like to know a quantitative percentage of improvement that is obtained from a weight distribution system. Maybe someday i will get around to it.

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I weighed all axles with everything hooked up and then with the weight distribution disconnected.  That was on a Komfort 27' travel trailer and a 1999 GMC half ton pickup truck.

In my case it moved about 200 pounds to the front of the truck from the rear.

To Lowell- many people weight their front axles when setting up their WDH. The hard part for most folks is finding a scale they could use

Lou beat me to the trailer weight link.

Tongue wt is kind of like the Price is Right game where you must choose a number between the price of two prizes.  In the tongue wt game, the number MUST be MORE than 10% of the loaded trailer wt  and MUST be LESS than remaining Payload capacity.  Any number in between is fine.

grashley said:

Lou beat me to the trailer weight link.

Tongue wt is kind of like the Price is Right game where you must choose a number between the price of two prizes.  In the tongue wt game, the number MUST be MORE than 10% of the loaded trailer wt  and MUST be LESS than remaining Payload capacity.  Any number in between is fine.

Click to expand...

Well put!