Finally hit the scales

handye9 wrote:
The measurements came about because, that is the recommended method in the owners manual. Ford says, measure the front and rear bumper. One of the local hitch salesmen told me to measure fender wells.

The fender well measurement (unloaded and loaded with WD) showed no rise on the front.

When you measured at the front bumper, you got a rise of 1/2".

When you later measured at the fender well, you got no rise.

This is why I recommend that, if people really want to know what the WDH is doing, they should measure the axle loads and not rely on height measurements.

Your axle loads indicate a Front Axle Load Restoration of 200/440 = 45%.
Your axle loads indicate that after WD was applied you ended up with 240# removed from the front axle -- which should give a front-end rise of about 1/4".

It looks as though you have a good compromise between the 2008 specifications and the specifications which have been in effect since 2011.

Ron

Ron Gratz wrote:
RETURNING TO THE ORIGINAL POST ---

Or, if you don't want to do that, you might want to consider that the "theoretical" values above are closer to reality than the measured heights.
That would mean the actual front end rise, after application of WD is closer to 1/4" than 1/2" -- which would mean you are not at the extreme limit of the "acceptable" range.

Ron

The measurements came about because, that is the recommended method in the owners manual. Ford says, measure the front and rear bumper. One of the local hitch salesmen told me to measure fender wells.

The fender well measurement (unloaded and loaded with WD) showed no rise on the front.

It is close enough for me, I don't think more measurements are needed.

RETURNING TO THE ORIGINAL POST ---

In the first post of this thread, the focus was on axle loads and we provided comments on your analysis of them.

Now the focus has turned to fender heights. Due to the very unusual sequence of height changes which were reported, I think it would be good to comment on what was measured versus what normally would be expected.

The 2008 F-250 4x4 is available with seven different front spring coefficients ranging from 349-499 lb/inch per spring. Not knowing which pertains to your TV (and not knowing if you have modified the front springs), I will use an average of 423.3 lb/inch, which gives a combined front-axle coefficient of 847 lb/inch.

The analysis of the your measured loads and heights plus the theoretical height changes is given below.

column 1: measured front axle load change
column 2: theoretical front height change assuming spring coefficient = 847 lb/inch
column 3: measured front end height change

______from "TV only" to "hitched with no WD": -440# +0.52" +1/4"
____from "hitched w/ no WD" to "WD applied": +200# -0.24" +1/4"
NET CHANGE from "TV only" to "WD applied": -240# +0.28" +1/2"

The first unexpected result is the measured height increase of 1/4" which is only about 50% of the theoretical value of 0.52".
The measured height change is in the correct direction, but corresponds to a front axle combined spring coefficient of 1760 versus a more likely value in the range of 700-1000#.

The second unexpected result is the height increase of 1/4" in response to a load increase of 200# -- the height should decrease when the load increases.

The third unexpected result (related to the second unexpected result) is the net height increase of 1/2" in response to a net load decrease of 240#. That corresponds to a front axle combined spring coefficient of 480 lb/inch.

I've analyzed a lot of load data, a lot of height data, and some combined load and height data.
My advice would be to re-do the height measurements to see if you can reproduce the reported values.
Before each measurement, you should bounce the front end up and down to see if you can get it to return to some repeatable height.

Or, if you don't want to do that, you might want to consider that the "theoretical" values above are closer to reality than the measured heights.
That would mean the actual front end rise, after application of WD is closer to 1/4" than 1/2" -- which would mean you are not at the extreme limit of the "acceptable" range.

Ron

Ron Gratz wrote:
Are you saying that when you hitched up with the 1200# Drawtite and applied WD, the front of your truck ended up being 3/4" above the unitched height?

If so, your Drawtite bars must have been significantly under-tensioned.

With 1180# tongue weight and 1200# bars, you should be able to get the front end back to the unhitched height.
Did you measure the front-end rise when hitched with the Drawtite, but with no WD applied?

Ron

I didn't measure front end rise (hitched with no wd) on the drawtite. I don't think the bars were undertensioned. I used tongue jack to raise the tongue and rear of the truck, then the pipe to pull up the snap brackets. The were plenty tight. The front end rise was 1/4 inch higher than I had with the Andersen hitch. I do have to say, the drawtite is old and pretty well worn, so, it may not work as a new one would.

I got this from Andersen.

"We do realize that in some cases –depending on the truck/trailer set up– we are 'softer' on the weight distribution side. In the past we have seen vehicle manufacturers ask for 70, 80 and even 100% of the lost weight to be returned to the front of the vehicle, but as vehicles have advanced in suspension and design over the last several years we see many mfrs slowly changing that number to be closer to 50%. Our goal is to get the tow vehicle close to level, but there is no need for perfect leveling (or a specific percentage of reclaimed weight) when it is designed to carry a load just fine. I recently had a customer who said that his trailer tows perfectly now and is the smoothest ride ever, outshining his 'other-brand' WD hitch, but he noticed the numbers on the scale were different and it didn't move as much weight forward as his old hitch. I had to smile and say 'It doesn't matter if the numbers aren't the same –as long as it works well." Again, we want to make sure the tow vehicle is not drastically 'un-level', that is what is important, not the exact numbers. If everything feels good and it is towing well, perfect numbers aren't really important. After hundreds of installations we have found that it is just as effective to basically "sight level" the tow vehicle and get it as close to level as you can by tightening/loosening the Tension Nuts or making small adjustments to the height of the ball."

It pretty much describes my situation. It does tow pretty well and it meets Ford spec for leveling the vehicle, but, the FALR numbers don't look good to those who insist on 100%.

I went to another hitch place today. This guy told me the exact opposite as what I was told yesterday. This one looked at measurements and scale sheets, and said "that Andersen hitch is doing what is is supposed to be doing. You don't need 100% FALR as long as truck and trailer are close to level as you can get (same thing Andersen told me), and he looked at my drawtite hitch and said the wear is mostly caused by the grease collecting dirt, which grinds down the metal." Yesterday, the other hitch guy said it was wearing down because it didn't have enough grease.

Yesterday, I was told I need a new hitch. Today, I was told, you got it rite, keep using it, come and see us if and when it wears out or you don't like it.

handye9 wrote:
I still have the old hitch, and, I took it along today. After hitching up and measuring with the Andersen, I did the same with the Drawtite (1200 lb) trunion bar hitch. Front of the truck was 1/4 inch (over the plus or minus 1/2 inch) higher than with the Andersen.

Are you saying that when you hitched up with the 1200# Drawtite and applied WD, the front of your truck ended up being 3/4" above the unitched height?

If so, your Drawtite bars must have been significantly under-tensioned.

With 1180# tongue weight and 1200# bars, you should be able to get the front end back to the unhitched height.
Did you measure the front-end rise when hitched with the Drawtite, but with no WD applied?

Ron

Ron Gratz wrote:

handye9 wrote:
Your interpretation is correct. I called Ford. Apparently, for 08 F250, they were more concerned with measurements than weights. I was told to "do the measurement front and back, hitch up, and measure again. Front should be no more than (plus or minus) 1/2 inch of unloaded measurement and rear should not be any higher than unloaded measurement."

One interpretation of what you were told by Ford is that zero difference from unhitched is optimum and up to plus or minus 1/2" deviation is acceptable.

If that's the case, then it's up to you to decide whether you want to settle for "acceptable" or try to get more load distribution to get closer to "optimum".

Ron

That's true. As long as rear end is lower (they don't say how much) and front end is plus or minus 1/2 inch of unhitched measurement. That's what is in the owners manual. If plus 1/2 inch is acceptable, that is not 100% FALR, and, any minus measurement would be over 100%. I have the 1/2 inch at 45 - 50% FALR.

Except for 100% FALR, my scale numbers look good, my measurements meet Ford specifications, and overall, the ride is smoother than with my old hitch. I still have a little wiggle with bow wave. More from mini vans than big rigs. But, getting rid of all of it, would be impossible. I did the scales out of curiousity, mostly, and started this thread to see if my calculations were correct. I think it was you, who asnwered that. The rest, kind of blossomed.

I still have the old hitch, and, I took it along today. After hitching up and measuring with the Andersen, I did the same with the Drawtite (1200 lb) trunion bar hitch. Front of the truck was 1/4 inch (over the plus or minus 1/2 inch) higher than with the Andersen.

I don't know what to think about that hitch salesman. According to him, anything less than 110% FALR is bad weight distribution. I didn't have the heart to tell him that GM is onboard with 50% on some of their trucks. He has a Chevy and appears to be a little partial.

handye9 wrote:
Your interpretation is correct. I called Ford. Apparently, for 08 F250, they were more concerned with measurements than weights. I was told to "do the measurement front and back, hitch up, and measure again. Front should be no more than (plus or minus) 1/2 inch of unloaded measurement and rear should not be any higher than unloaded measurement."

One interpretation of what you were told by Ford is that zero difference from unhitched is optimum and up to plus or minus 1/2" deviation is acceptable.

If that's the case, then it's up to you to decide whether you want to settle for "acceptable" or try to get more load distribution to get closer to "optimum".

Ron

handye9 wrote:

MM49 wrote:
It looks like you have your SES set to high. Do you have the 1" rubber spacer in?
MM49

SES is not supposed to engage until there is a load. Installation instructions specify a 1" gap (when unloaded) between the axle and Timbren spring. That is what I have. If I put spacers in, there would be no gap, and SES would be engaged all of the time.

Part of the confusion may be the rear spring blocks have been changed.

This truck came from factory with snow plow package. Due to heavier front suspension, it looked like it was squatting, with no load, whatsoever. On level ground, rear fender wells were 1,5 inches lower than the front. The fix for squatting appearance was, remove the 2" F250 spring blocks, and install 4" F350 spring blocks. Now, on level ground, rear fender wells sit .5 inch higher than the front. Could be why I have no room for SES spacers.

I sounds like you have a good understanding of the problem. I agree with your assessment. You are dealing with a squat butt Ford rear suspension.
MM49

"No amount of lift is good.........."

Those guys must really know what they are talking about and should be designing vehicles for GM instead of peddling hitches. Wait a minute! Is there a chance that they have a vested interest in requiring that everyone restore their front axle weight to 100%? What other stuff should we disregard in the owner's manuals?

handye9 wrote:
Then, I went to a place that sells hitches, went over the numbers with them, and was told "no amount of lift on front is good, they don't care what the owners manual says".

Have you tried to get enough load transfer from your Andersen WDH to return the front end to its unitched height?

How much Andersen bushing compression are you using to get back to 1/2" of front-end lift?

Ron