visited CAT scales - the numbers are in...

[slowmover]

Okay, ya'll, I've had a Hensley on my vintage kin SILVER STREAK that Dave Tidmore and crew installed for me at Roger William's Airstream a few days after I purchased both truck and trailer. We've put probably 5,000-miles on it since May and I now have a little time to start the rest of the process of perfecting the tow vehicle and trailer for roadworthiness.

I've posted elsewhere my "feelings" about this hitch. It's a no-brainer, IMO. But my rig is not otherwise ideal. Not yet.

I grew up in a family that towed (Streamlines and Silver Streaks), and I have been a professional truck driver. I've usually owned old cars (just let go my '71 Chrysler daily driver). "I've learned and learned", as one old truck driver said one day, "and I still haven't seen it all"; a statement I agree with in my more temperate moments.

So I'd like to enlist your help in tracking down, through this thread, some if not all of the "roadworthiness" issues (balance, distribution of weight, etc) that can be encountered per my rig. Perhaps this will be of help to others. I have had to go to a lot of threads in this forum (and others) to find info on rigging properly (I am going to use A/S guidelines even though I do NOT have independent suspension on my trailer; please ask for any clarifications). I'd rather use this forum than others out there with no further comment.

No, I do not have a camera I can post pictures with at this time.

We'll be leaving Dallas in a few days bound for Corpus Christi (again) and I'll have the time to do some Cat Scale weighing, and rig measurements.

Your help is requested.

According to Andy/Inland RV I'll need:

1. Length of Trailer
2. Tongue Weight
3. TV Wheelbase
4. TV Spring Capacity

Also,
A. Truck Scale
B. Straight Edge (and level)
C. Tape Measure


TRAILER

1983 Brochure Picture (mine is nearly identical; a rear bath; brochure has fair info)
1983 Silver Streak Brochure Cover

1983 34' SILVER STREAK 3411 Supreme
As of 8/8/07 weight was 7,360# (tongue weight not measured)

This weight represents a current load that is changing monthly as we travel (not retired, deciding future jobs, where to live and the like. Plus, visiting our son as much as possible before he is shipped out by the USMC), so I expect to see a change on Thursday when I re-weigh. My future weight is unlikely to be higher than this.

When purchased, the trailer was nearly dead-on the factory weight of 6,820#.

TOW VEHICLE

2004 DODGE RAM SLT Cummins TurboDiesel, 2WD, 3.73 Anti-Spin, NV-5600 6-speed, QuadCab, 8' bed. 8,620#, hitched, fueled, usual load otherwise. A separate weigh will be made this time.

DODGE TOWING GUIDE
Dodge Towing Guide

Gross Vehicle Weight Rating (GVWR) = 9000 lbs
Payload = 2274 lbs
Curb Weight = 6726 lbs
Curb Weight Front/Rear = 4071 lbs/4071 lbs
GAWR Front/Rear = 4750 lbs/6000 lbs
Gross Combination Weight Rating (GCWR) = 20000 lbs

TRUCK SCALE TICKET
(full fuel, one pax, topper, bed with good load)
Steer: 4,240
Drive: 3,760
Gross: 8,000#

I will be taking static measurements of the vehicles the day of the weighing set once at a CAT Scale; trailer beltline, wheelwells of both vehicles, etc. Hitched and unhitched.

I will also be splitting the tandem axle on the scale in as level a manner as possible, as I believe I have a significant rear-ward bias due to the floorplan of this trailer.

ORIGINAL WEIGH TICKET: (with oem Reese hitch; truck with no load)
Day of purchase

Steer: 3,900
Drive: 4,160
Trailer: 6,000#
Gross: 14,060

SECOND WEIGH TICKET: W/D bars at max
(TV with full fuel, usual bed load and passengers. TT with full fresh water, empty waste tanks, empty propane [two 40# bottles]).

Steer: 4,060
Drive: 4,560
Trailer: 7,360#
Gross: 15,980

(A quick, but imperfect tandem split indicates a 3-400# rearward bias).

What information would you have me gather to get this underway besides the above?

Thanks in advance.
__________________

[2airishuman]

hi rednax

one item i've learned since the first weigh in...

at some/many scales you MUST roll off and come around again for each spring bar/set-up adjustment.

some scale sections (rear primarily) will NOT reset and measure accurately unless unloaded between measurements...

so ASK about re-weighs (which are only 1-2$)

btw i've since ADDED an extra leaf to the truck rear AND changed to a higher spring bar rating (1400)

with the original set up and at 30-35,000 miles of towing the truck began to sag slightly at the rear...

max bar tension NO LONGER redistributed load as first posted and the drive axle became too heavy.

so KNOWING tongue weight is important (mine is >1300lbs) and the newer 3/4-1 ton spring sets are more NOT nearly as stiff/harsh as 60s-70s-80s trucks.

leaf spring fatigue with lots of towing is not uncommon.

IF your goal is to reduce truck vibration into the trailer, consider the mor-ryde rubber rear shackle replacement...

i've posted that link in other places...

cheers
2air'




cheers

2air'

[slowmover]

Thanks, 2air,

I used to weigh loads 5-7 times weekly as an OTR driver. I've had two discussions with CAT techs (oughta see their service trucks, whoa!) and have had to slide the rear tandems more times than I care to think about and re-weigh to not violate what is commonly called "the bridge law".

The above numbers are from across several months, and about 10-11 tickets, all but three are re-weighs (like you, I'll not bore everyone with details; about how much my weight dropped off from full fresh water to empty fresh water, etc).

Thanks for the info on springs weakening, and what you've done. I am not full-timing at this point so am willing to experiment somewhat. I'd be more likely to order up a custom leaf pack to fit the bill if I were full-timing and had a better grasp of this issue vis-a-vis my rig. And I'll bet that Dodge trucks are more stiffly sprung than the competition. Do you recall what your spring capacity is, and what you have (numerically) increased it to?

Am familiar with the Mor-ryde options; I'd like to also fit their Ind/Susp to my trailer as retrofit. AND disc brakes.

My concern is NOT with ride quality at this time. A truck is a truck. But the motions affecting the trailer are not to be ignored.

By the way, any of you know the drive-axle-to-rearmost-trailer-axle distance on your doubles or triples? I think mine is a bit longish, and would like to compare. Also, the length from hitch head center to that same rear axle hub/point.

Thanks all. I look forward to your advice and comments.

[2airishuman]

Originally Posted by REDNAX

SECOND WEIGH TICKET: W/D bars at max
(TV with full fuel, usual bed load and passengers. TT with full fresh water, empty waste tanks, empty propane [two 40# bottles]).

Steer: 4,060
Drive: 4,560
Trailer: 7,360#
Gross: 15,980

ok, final comment this round.

was this with the reese or haha? not that it matters from a w/d perspective...

this last ticket suggests that whatever spring bars you have, they are less than the tongue mass...

which WILL go up another 80lbs with lpgas on board and that will translate into another 100+ lbs on the drive axle.

fully flexed you don't appear able to evenly balance the load distribution, and that may not be your goal...

there are lots of guideline on steer/drive loads...

and my truck felt really good towing with 50/50 as noted in the o.p.

the set up was declared 'perfect' by those who know this stuff....

your measurement difference is within the '10% rule' without lp gas and may still be after adding lp gas.

recently as an experiment i towed 5k miles with the drive axle 900 lbs heavier than the steering axle or right AT 10%...

tire pressures were adjusted to the load difference.

the steering felt a tad lighter (if 4400 lbs is light) for the first few hours but i soon adapted and the lightness vanished.

i towed this way at up to 75 mph over mountains, with high winds, in urban commuter traffic and through snow, rain and hail. yes hail.

the ONLY differences i reliably could find were...

1. slightly higher tire temps on the drive axle (about 8-10 degrees)

2. 3-4/32nds MORE tire wear on the drive axles after 5,000 miles...

but steering control and drive stability seemed no different from towing with more load on the steering wheels.

so my point is the rules for balancing steer/drive axle loads exist, but perhaps they aren't fixed and absolute.

cheers
2air'

[nickcrowhurst]

Originally Posted by REDNAX

According to Andy/Inland RV I'll need:
1. Length of Trailer
2. Tongue Weight
3. TV Wheelbase
4. TV Spring Capacity
What information would you have me gather to get this underway besides the above?

I suggest you also need:
5. Length of rear overhang on tow vehicle from rear axle to hitch ball.
6. Length from trailer hitch to center of trailer axle system.
7. Length of load distribution bars.

If you read this thread:
http://www.airforums.com/forums/f464...sis-19236.html
and punch your numbers into the equations, you should gain a greater understanding of your rig, so as to make more informed decisions.
Nick.

[slowmover]

2Air, those numbers are with the H/A. I first "studied" them as a result of your thread (and my ensuing search on this forum and others), but I somehow missed Crowhursts outstanding thread.

After driving this rig again last night there is, again, no problem about "sway" because of the H/A. Still, it rides nose high with a trailer whose floorplan has all the heavy items and closet storage on or behind the tandem axle; the front of the trailer is quite open and features little beyond some kitchen cabinetry and moveable furniture (original owner did not order either of the two dinette options and minimized overhead cabinetry). We removed the sleeper sofa and some other cabinetry and have reduced axle forward weight by 100-200# that way.

This (I believe at this point) exacerbates the rocking motions which concern me; that the trailer is tail heavy. The stiff rear TV suspension sets it going.
Maybe, just moving to a 4" drop will suffice. We'll see.

The tire inflation is down by 10% from rated max and I noted a 10F difference between the front and rear TT tires on a break at a rest stop. The usual difference (fully-inflated) is about 5F.

I'll be weighing at a Cat Scale south of Waco, TX later this morning, and will provide all the numbers for the Crowhurst calculator. I re-weighed the truck separately yesterday.

[slowmover]

Allright, weights and measurements on the Silver Streak


Truck, solo

Steer: 4,320
Drive: 3,580
Gross: 7,900
F/R bias: 55/45


TT & TV, 8/10's of W/D max; TT tanks empty

Steer: 4,140
Drive: 4,500
Trailer: 7,460
Gross: 16,100

Truck gross is: 8,640
FF/RR bias: 48/52
Spread is: .9
TW to TV: 740
TW to TT: ??? (140 registered, 240 needed)


Second scale tkt: (yes, amigo, drove off & back around)

Tongue: 980
TT Axles: 7,320
(TW: 13%)
Had to lower tongue 2" to level.

(On some old scale tkts, the rear tandem is experiencing 400-600# bias to the rearmost axle; I am tail-heavy w/o question)


Andy/Inland RV & Nick Crowhurst Q's:

1. Trailer length, hitch center to rear bumper: 35.3'

2. Tongue weight: 980#

3. Tow vehicle wheelbase: 161"

4. Rear spring capacity: 6,000#

5. Rear overhang (axle center to hitch center): 76"

6. Hitch center to TT axle center: 260"

7. Length of bars: 35" +/- (H/A hitch; silvered bars)

Other numbers: Ttl length of combination: 61'
Spread from TV to TT: 64" (body-to-body)


TV specific:

FF end (fenderwell)
Buckled: 35"
Unbuckled: 34.25"

Tires at 63% (50-psi) factory-spec for all loads.

RR: (same)
Buckled: 36"
Unbuckled: 36.25"

Tires at 88% (70-psi) factory spec for MAX load


TT specific:

FF axle (fenderwell)
Buckled: 26"
Unbuckled: 26"

RR axle: (same)
Buckled: 25-5/8"
Unbuckled: 26"

Tires at 100%

[2airishuman]

ok i'll start b4 those who know get here...

the numbers don't look unreasonable...

it appears that even with the w/d at 8/10th...

your 980 lb tongue has added 920lbs to the drive axle, while reducing the steer axle by 180lbs...

not a great difference on the steer axle or f/r distribution, but still...

now IF the trailer is nose high with the 2 inch drop

isn't a 4 inch drop going to increase the effective tongue mass?

while improving the effect of the spring bars?

also that's without fluids?

how big is the fresh tank and where is it relative to the axles?

did you have lp gas in the bottles?

did you get a ticket with the w/d fully relaxed but still hitched up?

i'm not sure what 8/10s means but tightening the screw jacks up to beyond (by 1") the last mark,

which is the most 'tense' position, moves several hundred lbs on my unit.

cheers
2air'

[slowmover]

Yes as to changing to a 4" drop, I believe that the w/d will work better. That will be the first change (to order on Monday).

Fresh water tank is over axles; empty on this ticket; full adds 340-lbs.
LP gas 40# bottles are full (aluminum tanks).

No ticket this time with bars backed off; I had two trucks backed up already. Fueling and weighing had already consumed an hour.

8/10's, in this instance, meant I was 2" from case covering shaft; that is, 2' showing on inner portion. I use tape measure all over the place, kinda like that handly little 18V Ryobi drill motor.
(Found an old pair of tkts, different load: notes not great but looks as though an additional 50# was placed on front with max W/D).

[2airishuman]

tail heavy no, but perhaps widely spread...

red'

with the tongue at 13% the trailer isn't really tail heavy, right?

now IF some your heavier gear is way back and way forward, this isn't ideal,

even when the tongue is 10-15%...

i'm no engineer but a widely placed load affects the rotational dynamics and handling negatively, i think.

the haha could mask symptoms of this (yaw) but it isn't ideal.

also with the higher cog on the ss the rotational axis? is important.

a/s do handle better with water on board and most heavy gear stowed near the axles...

that must be true for the ss too...

cheers
2air'

[slowmover]

Sure, this is a leaf-sprung buggy with shock absorbers (HADCO axles). It rides fairly close to the ground (fully enclosed belly) and the springs have a very short movement. Not as nice as A/S; that I/S is superior without question (except in longevity and maintenance).

The reason I say that it is tail heavy is that all of the "furniture" and appliances and water tanks start at the axles. It is pretty much wall-to-wall floors the first seven feet, and the next seven includes only the kitchen sink/counter. The majority of weight is on or a few feet aft of the axle tandem. Preferably there would have been more furniture forward to offset this rearward bias, but the original owner didn't spec it so.

Yes, 13% looks okay, but remember that is with the trailer leveled, a position it is not riding in. I'm pressing down on the rear axle (you should see tires at rest when hitched, it's obvious) and doubt I am seeing a "proper" amount of tongue weight, especially underway. Yes, the H/A is covering incipient sway. Thus these post requests for help, so I don't leave anything out (and before I get too busy with a new job, etc).

The original REESE hitch rode quite well (level). My truck receiver and the PO's were at the same height. In fact I towed the trailer over 30-miles w/o sway control to see how it would do, and it never jumped me (on my way to Williams Airstream to have H/A installed.) Barely twitched in fact, (similar to some boat/trailer combos of the same weight).

My parents bought their 28' S/S in 1976 or so, and the floorplan, while not as open, was better from the standpoint of weight distribution. All S/S have underfloor tanks, nothing is above the frame. Theirs was easy to tow (used a Cadillac the first twelve years) and never balky. This one is hanging back on me like a tired kid with the current hitch rigging, exacerbating floorplan trade-offs.

[nickcrowhurst]

The Load Distribution Hitch Calculator calculates the chain tension required to restore the steering axle to its height before the trailer was attached. It does not calculate the higher tension required to put extra weight onto the drive axle. The result after punching in your figures is:

Load Distribution Hitch Calculator

Inputs
W= 161 inches (Wheel base of tow vehicle)

H =76 Inches (Distance from tow vehicle rear axle to hitch ball)

T =980 Pounds (Tongue weight of trailer)

L= 260 Inches (Length of trailer from ball coupling to mid-point of axle system)

B= 35 Inches (Length of load distribution bars)

Outputs
R =1443 Pounds (Extra load on TV rear axle before chains are tightened)

C =463 Pounds (Uplift on front steering axle when trailer is attached but chains not tightened)

Now the chains are tightened to bring the front axle back to its original height :

D =1647 Pounds (Total chain tension required to restore front axle level)

U= 684 Pounds (Reduced loading on TV rear axle caused by chains being tightened)

E= 758 Pounds (Final loading on TV rear axle with trailer attached and chains tightened)

A =222 Pounds Load transferred to the trailer axles

Use at your own risk! (My son, a U.S citizen, tells me I have to add this in the USA!)

The calculator is designed as an aid to understanding what is happening to your rig, rather than dictating what you should do.
Nick.

[slowmover]

Thank you, NickCrowhurst, for the development of your calculator, and its' application here. (Granted, it's use is as an exercise). I downloaded, but couldn't get it to work.

Given original numbers for the TT at 7,320 (TW 980) I should be seeing ("might" be seeing), once buckled up: 7,542 at the TT axles with the Crowhurst Calc. I am seeing 7,460; a difference of 80-lbs. So, short on rearward transfer.

Using Andy/Inland RV Ctr numbers of 2/3 TW forward, and 1/3 to the TT axles, that TW of 980 would be split: 647# onto the TV, and 323# onto the rear axles (with the TV numbers split near evenly between the FF & RR axles). One-third of 980 = 323#, and I am getting only 140#.


On the TV, with original numbers of 4,320 Steer, 3,580 Drive, I "ought" to be seeing 4,330 on the Drive according to the Crowhurst Calc. I am seeing 4,500 at present. Same as the above, not enough weight transferred onto the TV front axle and TT axle; it's mostly going to the TV drive axle.

With Andy/I-R-C suggestion it ought to be 323# to Steer and Drive axles, approximately (or, @ 3,900 on the drive axle).

At present, nearly all the weight is going to the Tow Vehicle drive axle, no real W/D happening (and I did not have the hitch jacks screwed all the way tight).

I won't be moving again for a couple of weeks (have to get 2" drop stinger swapped for 4" drop as well), so will be back with more work after re-rigging. I'd like to see closer to 50/50 weight distribution on the TV, and see if I can't get the rear-ward weight bias off the TT tandems after some re-arranging of items to the truck bed. I'll be weighing the trailer axles split onto two scale pads this time as well.

I don't quite grasp what the different weight ratings of bars are capable of, but that will be the third set of rig weights after the second obviously needed here.

Am looking forward to more results and am very apppreciative of the help offered here.

[nickcrowhurst]

Rednax, the calculator will not work online unless and until the forum administrator permits the attachment of Excel spreadsheets. I am awaiting a response on that issue. I have today added a relevant post to the Load Distribution Analysis thread. You may find it of relevance to your current quest:
http://www.airforums.com/forums/475541-post61.html
Nick.

[slowmover]

I have done some re-arranging (re-packing) of trailer storage items to the truck; moved maybe 120# but most of it was from the last two feet of the trailer.

I have confirmed that I have 1,000-lb W/D bars and have ordered a new stinger to drop the hitch ball down to level ( I can understand the dealer having installed it as done; it is a coin flip. But towing it is a different matter than just eyeballing it).

I can't use the .xls spreadsheet, but it sure is good to see it available. I have been reading the referenced thread linked, and am trying to digest what I've read.

I much appreciate the help, as life otherwise is busier than I can describe in a short paragraph; coming home to the trailer and working on this has been a real relief: I feel I have some direction now on fixing what I see as [a] road-ability problem[s]

[Mikethefixit]

Ok I promised 2 air I would post my weight findings when I got them.
This is an 01 F350 S/W 7.3liter Diesel Crewcab 8ft bed. 3/4 tank of fuel and abt 35 gal of fresh water on board.Small amount of food and clothing.Blue Tote and misc items in the bed.
Steering <<<<<4120
Drive<<<<<<<<4580
Trailer tandem<<5060
Gross <<<<<<<<13,760
Although the axles are at the end of their life and new axles due to arrive any day ,we find that this balance of weight gives us/the truck and trailer a smooth ride.
It is very important to Use the CAT scale and get the balance correct.

[2airishuman]

Originally Posted by Mikethefixit

...It is very important to Use the CAT scale and get the balance correct.

good info roger! and the numbers look great.

are you using w/d bars?

if so, what rating and adjustment?

cheers
2air'

[mustang]

It Is great info Air, I have a question. is it proper to load a steering axle the same as a drive axle? as with case number 3

[Mikethefixit]

2air
I'm sorry U ask a question in June that I don't remember even seeing.
The hitch is an OLD Duel Cam Reese I believe.It has no names or ratings on the bars. I thinks there is a number and 1 word "TOP" at the base of the bars to show which side should be up.
I think there are 7 links in the chains of which I use the very last one. I tried goin up one link to 6 but WHOW NELLIE that was the wrong thing to do. The ride and handling went bye bye. I'm glad we wear seat belts. It was rough.
I need to get back across the scales to see where we are since I changed axles on the trailer. I gained about 4" in ride height. I had used a BLUE OX 4" drop in the drawbar, to get the ball height down and keep the trailer level because of the hitch height of the 1 ton.I have since removed the drop and I am only the tip of a bubble off from level. I use 2 different levels that are not attached to the rig. I do have points where I check for level.Works for me.
I do check tire temps when we stop (check only with my hand) temps seem to be running normal all around the rig.
I am satisfied with the set up and the comfortab;e ride it gives us. We even leave things (no breakage of course) on the table and counter tops,nothing on the floor yet.LOL
Will keep you informed 2 air
Roger

[Mikethefixit]

Mustang
I wouldn't shot for equal weight on the steering. U know I have the 7.3 liter Harvester Diesel. F350SW/Crew/8ft.
Before I change trailer axles my weights were
Steering 4120
Drive 4580
Trailer Tandem 5060
Total Gross 13,760
This gives us as perfect a ride as I can get.
Hummm 45 yrs of big trucks has come in handy
Roger
PS Possibly we will make the Rally on the lake.Wife said yes. So we will see how the weather shapes up.