Tuning Andersen WDH + 2019 Expy Max XLT

[JasonH]

The Endurance are supposed to be good tires, so you should be fine in that regard. I still suggest a TPMS. I picked up a nail on a trip from Texas to Florida, and only caught it during visual inspection while refueling because the screw was on top. The tire was already 10 psi low. I purchased a TPMS immediately after arriving in Florida. I also suggest several cans of fix-a-flat, and two bottle jacks, because you have a lot of tires. Familiarize yourself with changing tires on the trailer. On dual axles, one wheel drops while you lift the other, so you need a lot of height. I use leveling blocks under the bottle jacks to get tires off the ground.

Regarding front braking, the objective is to return 50% of the weight removed from the front axle when you place a load on the rear. You want to keep enough weight on the front to retain steering and braking control. Scenario 2 is closer to optimal.

It seemed as though you only had a half tank of fuel when you visited the scale. Adding more fuel, people, and personal items may lift the front even more. Also, your tongue weight could be a little higher. If you increase the tongue weight some of that weight will need to go to the front. And when you pack for a trip, if you put everything in the trailer (as you should) you'll increase the tongue load even more. Ultimately, you're very close to where you need to be now, but may probably wind up needing another 100 - 200 lbs in the front. You'll have an idea of what changes are needed when you start driving. If the trailer sways, more weight is needed on the tongue. If the steering feels too light, more weight is needed on the front axle.

 

[Joey Smith]

Thanks for all the tips/comments.

I have a small ramp to raise a tire in case it goes flat: Trailer Aid Plus

Anyone ever used that?

Supposed to provide a 5.5 inch lift and is meant for dual axle TT’s. Seems to make sense but I have not yet had a reason to use it.


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[JasonH]

Thanks for all the tips/comments.

I have a small ramp to raise a tire in case it goes flat: Trailer Aid Plus

Anyone ever used that?

Supposed to provide a 5.5 inch lift and is meant for dual axle TT’s. Seems to make sense but I have not yet had a reason to use it.


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The best advice I can give is try it out before you actually need it. Also make sure you have the correct sockets and breaker bar or ratchet to remove the lugs.

 

[Joey Smith]

I took some measurements of the TV and TT (but without my family in the car). Hoping that still gives some info on tuning the hitch.

TV only:
TV Front: 36.25
TV Rear: 36
TT Front: 17.5
TT Rear: 16

TV+TT (no WDH)
TV Front: 36.75
TV Rear: 34.75
TT Front: 15.25/15
TT Rear: 17/17.25

TV+TT (w WDH - 7 threads)
TV Front: 36.75
TV Rear: 34.875
TT Front: 16/15.75
TT Rear: 16.5/16.5

TV+TT (w WDH - 8 threads)
TV Front: 36.5
TV Rear: 34.75
TT Front: 16/15.75
TT Rear: 16.5/17

I am thinking the 8 threads case is best for the front axle height.

Is this increase from 36.25 to 36.5 (or even up to 36.75) going to have noticeable impact on braking?

I have been driving a little but have not yet noticed issues but I have really not driven more then 40 minutes or so on residential streets and 30 minute stints on pretty straight freeway driving (staying < 55mph)...


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[shane_th_ee]

Don't worry about the heights, worry about the weights*. There's two schools of thought on properly setting up a WDH.
School #1, the WDH should return 1/2 of the weight lost by adding the trailer back to the front axle. In this case, without the trailer, you're at 3120 on the steer axle without the trailer, and 2820 with the trailer and no WDH bars. This gives 300lbs difference. Half of that would be 150lbs. With this method, your ideal steer axle weight (after attaching the bars) would be 2970. With 7 washers, you're at a steer axle of 2920. 2920-2820 is only 100lbs, which means 7 threads is not enough. 8 washers give you a steer axle weight of 2960. 2960-2820 is only 140, which is marginal at best, but within the scale tolerance**. I'd recommend trying another thread.

The second school of thought says the ideal setup would transfer 1/3 of the tongue weight should be transferred back to the steer axle, 1/3 to the trailer axles and leave 1/3 on the drive axle. Your tongue weight appears to be 700lbs. 700/3=233lbs. 233lbs of weight transferred to the steer axle would result in a steer axle weight of 3053lbs. This school of thought says you need at least one more washer, if not two.

Further notes: school of thought #1 is often "minimum" and school of thought #2 is often "ideal". Yes, the owners manual has comments in it about not overloading the front axle, but your weight tickets say you've got lots of room on the steering axle.
Also, aiming for 233lbs returned to the steer axle will help alleviate your rear axle weight giving you more usable payload in the Expedition. Without the bars, your rear axle weight is 4340. With the 1/3-1/3-1/3 setup, you'd be at 4340-466 or 3874 on your rear axle with the bars attached.

*Worrying about fender heights is for people who don't have access to a CAT scale and/or haven't done their homework on how to use one...
**Notice the difference total weights?

 

[Joey Smith]

Don't worry about the heights, worry about the weights*. There's two schools of thought on properly setting up a WDH.
School #1, the WDH should return 1/2 of the weight lost by adding the trailer back to the front axle. In this case, without the trailer, you're at 3120 on the steer axle without the trailer, and 2820 with the trailer and no WDH bars. This gives 300lbs difference. Half of that would be 150lbs. With this method, your ideal steer axle weight (after attaching the bars) would be 2970. With 7 washers, you're at a steer axle of 2920. 2920-2820 is only 100lbs, which means 7 threads is not enough. 8 washers give you a steer axle weight of 2960. 2960-2820 is only 140, which is marginal at best, but within the scale tolerance**. I'd recommend trying another thread.

The second school of thought says the ideal setup would transfer 1/3 of the tongue weight should be transferred back to the steer axle, 1/3 to the trailer axles and leave 1/3 on the drive axle. Your tongue weight appears to be 700lbs. 700/3=233lbs. 233lbs of weight transferred to the steer axle would result in a steer axle weight of 3053lbs. This school of thought says you need at least one more washer, if not two.

Further notes: school of thought #1 is often "minimum" and school of thought #2 is often "ideal". Yes, the owners manual has comments in it about not overloading the front axle, but your weight tickets say you've got lots of room on the steering axle.
Also, aiming for 233lbs returned to the steer axle will help alleviate your rear axle weight giving you more usable payload in the Expedition. Without the bars, your rear axle weight is 4340. With the 1/3-1/3-1/3 setup, you'd be at 4340-466 or 3874 on your rear axle with the bars attached.

*Worrying about fender heights is for people who don't have access to a CAT scale and/or haven't done their homework on how to use one...
**Notice the difference total weights?

Thanks for the great feedback. Very helpful to get some possible rule of thumb guidance on all of this.

Had some questions:
Question #1. How should I be measuring my tongue weight using the CAT scale numbers collected?

I used a Sherline tongue scale and it read 600lbs.

I also used the following CAT scale numbers:

TV Only:
Steer Axle: 3130, Drive Axle: 3360
Total: 6480

TV+TT (no WDH support)
Steer Axle: 2820, Drive Axle: 4340
Total for TV: 7160

I assumed the tongue weight was 7160 -4340 = 680lbs

Is this correct?
Do I need to subtract out the weight of the hitch (60lbs) from this to get the actual tongue weight? I assume I do not...

Question #2:
If I further tighten the chains on the hitch, I see that the TT is starting to tilt towards the TV slightly. Is this ok? Was concerned about further tightening in case it causes more tilt of the TT.

At least this is what I see when going from 7 to 8 threads:

7 threads:
TT front: 16
TT rear: 16

8 threads:
TT front: 16
TT rear: 16 3/4

Thanks again for the helpful info!


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[flying68]

If it is properly setup weight wise and the trailer is dipping, then you may need to raise your hitch height, assuming you are using an adjustable hitch, then you would need to recheck your weights just to be sure, but they probably won't change much.

 

[shane_th_ee]

Question #1. How should I be measuring my tongue weight using the CAT scale numbers collected?

I used a Sherline tongue scale and it read 600lbs.

I also used the following CAT scale numbers:

TV Only:
Steer Axle: 3130, Drive Axle: 3360
Total: 6480

TV+TT (no WDH support)
Steer Axle: 2820, Drive Axle: 4340
Total for TV: 7160

I assumed the tongue weight was 7160 -4340 = 680lbs

There's a few different ways to get the tongue weight. You can do steer+drive axle weights from TT w/TV (no WDH support) - TV only, or 2820+4340-6480 = 680. Or you can do total weight TT+TV (any measurement) - total weight TV only - trailer axle (TT w/TV, no WDH) = 12060 (or 12080, or 12100) - 6480 -4900 = 680 (or 700 or 720). And, yes, the scales seem to be accurate to +/-20lbs so you will get some variation. I'm partial to the 2nd method because the first step (total weight TT+TV minus total weight TV only) gives you the trailer weight.

And, no, you don't need to take out the hitch weight.

Question #2:
If I further tighten the chains on the hitch, I see that the TT is starting to tilt towards the TV slightly. Is this ok? Was concerned about further tightening in case it causes more tilt of the TT.

At least this is what I see when going from 7 to 8 threads:

7 threads:
TT front: 16
TT rear: 16

8 threads:
TT front: 16
TT rear: 16 3/4

I'm not sure how the TT rear rises without the TT front dropping, but... the rule of thumb seems to be that you want the trailer level to slightly nose down (<1.6"). If you start to exceed that, you'd drop the head down another hole on the shank.

 

[Joey Smith]

My measurements do look odd between the 7 and 8 thread cases on the TT...I very well could have messed something up when measuring.

In any case, thanks to all for the input.
This group has been key to helping me understand this stuff!

I think I sort of understand enough to tinker and tune (at least until I run into the next thing that confuses me...).

Thx!


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[JasonH]

Thanks for the great feedback. Very helpful to get some possible rule of thumb guidance on all of this.

Had some questions:
Question #1. How should I be measuring my tongue weight using the CAT scale numbers collected?

I used a Sherline tongue scale and it read 600lbs.

I also used the following CAT scale numbers:

TV Only:
Steer Axle: 3130, Drive Axle: 3360
Total: 6480

TV+TT (no WDH support)
Steer Axle: 2820, Drive Axle: 4340
Total for TV: 7160

I assumed the tongue weight was 7160 -4340 = 680lbs

Is this correct?
Do I need to subtract out the weight of the hitch (60lbs) from this to get the actual tongue weight? I assume I do not...

Question #2:
If I further tighten the chains on the hitch, I see that the TT is starting to tilt towards the TV slightly. Is this ok? Was concerned about further tightening in case it causes more tilt of the TT.

At least this is what I see when going from 7 to 8 threads:

7 threads:
TT front: 16
TT rear: 16

8 threads:
TT front: 16
TT rear: 16 3/4

Thanks again for the helpful info!


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The 8 thread allocated the appropriate weight to the front. If you add more items in the future, additional adjustments may be needed. Safe travels!