Tim, I just took a couple of minutes to again look at this thread, and I noticed that in your post made at  12.22pm on March 19 you have referred to GTM as 'Gross total mass' and likened it to ATM. This is totally incorrect,and may be causing you some confusion. GTM is Gross Trailed Mass, and refers to the weight on the van's axle group. ATM is total weight of van and includes weight on axles plus towball weight, or weight on jockey wheel. This may help you understand your figures for the moment, but still I will try to find time to offer help. Cheers

Hi all,
I have had the caravan on the electronic bathroom scales with an ability to measure in grams this afternoon. The results have been quite a shock and amazing - particularly the tyre on van rear bumper.

Ball weight before moving anything: 243.90kg (my primitive ball wt scales came in at 240kgs; not too bad at all). Weighbridge weighs in 20kg increments and came in at 220kgs; room for a margin of error.

Van ball weight after:

1) Removal of rear spare tire on bumper without bracket: 255.90kg (remarkable)

2) Removal of tire bracket on rear bumper: 257.1kgtire

3) Removal of both (2) gas bottles from A-frame: 237.60kg

4) Adding back gas bottles and loading 20L of diesel in jerry can alongside toolbox on A-frame: 266.7kg

5) After draining water from front 85L potable water tank: 256.2kg (both potable tanks same size and in front of most forward van axle): 256.20kg  (only a 10.5kg ball wt. difference - yeh)

6) After draining rear 85L potable water tank:  (awaiting it to drain )

Assuming I travel with the rear tank full (nearest axle) and have the valve to the forward most tank shut, that would equate to travelling with 2 x 1/2 tanks full, which is acceptable to me = van ball wt 256.2kg  (see point 5 above)


Now, I have also made the following decisions:

1) To place caravan spare wheel on my vehicle roof rack over the front axle;

2) To place Kojack (caravan tyre jack) + vehicle air compressor (20kg) just forward of Ford Everest's back wheels rather than aft in the boot space.


Calculation of the payload mass of van as a percentage of the ball weight now becomes:

1) Van payload weight: 2740kg (weigbridge yesterday) - van tyre & holder (30kg approx; I will measure on scales tomorrow) + 20L diesel (9.9kg) = 2,719.9kg

2) Van ball weight (minus van tyre & bracket with addition of 20L fuel) = 266.7kg

3) Percentage is therefore: (266.7/2719.9) x 100 = 9.8%    (I am well happy.)

With this alteration in weight distribution I will need to recalculate the weight on my vehicle's rear axle.  GlenJ - I will use your spreadsheet to do this once I obtain all necessary axle distances.

Are We Lost - thanks for the equation to calculate difference in weight over back wheels with a shorter hitch length.  I will use the E2 - WDH hitch with Sway Control to transfer weight to the caravan axles and front axle of my car.  Admittedly, I got quite despondent with the distribution of weight in the van and started feeling beaten.  This was largely because I considered the van ball weight was still light even when carrying a full payload of water (170L) with little else I could do to counter the heavy rear.

Fortunately, even without water in the forward tank the ball weight is not impacted greatly, i.e. 10.5kg

Removal of the rear tire from the bumper what's more increased the van ball wt. by 12kg; a real win!

PROPOSED FUTURE ACTIONS
I will hitch the van up tomorrow to the WDH and check with the additional ball weight whether it is still nosing up.  If so I will proceed to purchase a Mr Hitches 225mm hitch from Hall Towbar which will enable me to lower the front of the van.  I have about given up purchasing the genuine E2 6" shank since I learnt from the Oz importer of Fastway Products (Titan RV) the wait has been pushed out to end of April 2022.  After non-availability of supply since June 2021 they were expected to be available from mid-March 2022; and so it goes on.

My research today has confirmed that Mr Hitches has the same sized holes for the adjustable down shank as well as the same spacing two holes apart (63.5mm) as the E2 genuine product.  I will attend Hall Towbar tomorrow and select the right size down shank using my existing E2 hitch as a reference.  In addition, I will try and purchase a shank that I can reduce the length of in the receiver and attend an engineering shop if necessary to get it sorted.

I am getting my motivation back after being distracted by the whole saga over a month period.  This is largely due to the Nomads on this forum providing support, come what may.

Cheers and thanks guys, I am now getting close to hitting the road again.  Takes a lot to get a good (determined) man down ... you rippa!!!  and 'yes' rear axle weight remains a concern and I will need to calculate exactly what that is with the WDH tensioned yet again.

Tim,

In making my comment last night, I had missed that the Everest has a rear axle load limit of 1750kg. My Prado's has a rear axle load limit of 1800kg in standard form. I decided to get a GVM upgrade which gave me a few extra kilograms to play with for the rear axle. I know that a GVM upgrade does not give a greater GCM, but I was not looking for that anyway.

My third row of vehicle passenger seats have been "temporarily" removed. A friend has the similar seats removed from his Everest. A few kilograms of weight reduction if you are scratching.

My weights are similar to yours but the van has its two fresh water tanks, one each side of the axle group. The grey water tank (smaller) is further back but it can be drained more readily at appropriate places, so I don't consider the weight of its contents. Its spare tyre is mounted underneath the van, just before the front axle, on a swing down bracket frame. Not that easy to access but possible as I have changed tyres.

Also just a point, have you included the weight of occupants in the vehicle? I am not sure if anyone worries about their weight in their reckonings.

-- Edited by watsea on Monday 21st of March 2022 11:39:25 PM

Congratulations. Nice work.

May I add I went though this exercise back a few years back not long after buying our caravan. 

My first weigh up found we were 70 kgs overweight and 320 kgs on the towball, that was the shocker, 50kgs to much.

I sorted the towball weight by moving gas bottles back towards the caravan, got rid of the pipe storage unit, reassessed our storage.

We also asked our caravan manufacturer for a new vin plate from 2648 to 2748kgs.

We have 3 water tanks which we can fill legally, my surprise there is that makes very little difference to the towball weights. 

But I did wonder about the replacement of the spare wheel from the rear bumper. Ps. I have cut the excess material off the bumper bar a few kilograms saving.

The other thing I have trouble with is tire pressures, my thoughts are most people run them to high on the caravan. I would rather run them similar to the cars rear axle tyre pressures, specially on a dual axle.

My reason is A. The car has 1700kgs on the rear axle, manufacturer recommendation somewhere between 36 to 41psi. The caravan dual axle carrying approximately 1240kgs per axle, I did toss a coin up and run at 38psi. 5 years, 80000 kilometres mostly lay back touring, never in a hurry. 

My other thinking is with lower pressure the caravan will roll before it slides, that would happen in a corner but higher pressures  it will slide in a near straight line and once it starts to slide your in trouble.

Watsea & Radar - thanks for your comments - more food for thought. It is good knowing that others have been through the same initiation of fire.

A GVM upgrade to the rear axle. I'd imagine that was expensive. Would want the gains to offset the cost.

The WDH when on the weighbridge lowered the back axle weights from 1820kg to 1640kg (180kg diff.) by distributing approx. 50kg to the caravan axles and 120kg to the vehicle's front wheels. (Not exact because of weighbridge margin of error.)

I will keep in mind the prospect of removing the 3rd set of back seats as an option.  By the way, how much of a saving was that in weight?

For completeness, the difference in van ball weight with the potable tanks drained was as follows:

1) After draining water from front 85L potable water tank: 256.2kg - a 10.5kg ball wt. difference.

2) After draining rear 85L potable water tank, i.e. NIL potable water payload: 247.50kg - a further reduction of 8.7kg on TBW.

Total Van Ball Weight difference with Both Potable Tanks Drained (170 litres) was only: 19.2kg!  (I am relieved but surprised by this, 2nd to the difference removing rear tyre made to TBW scales.)

CONCLUSION

# Never attach items to rear bumper due to fulcrum over van's axles greatly impacting on ball weight.

# Similarly, avoid payload in rear of van at all costs to avoid pendulum effect and sway.

# The placement of a very few heavy items in the range of 1-25kg (combined) beneath bed before A-frame (where my potable tanks are located) does not greatly influence the van's ball weight.

# Whether I travel with the potable tanks full or not I have a variance in ball weight at most of: 19.2kg  (so less of a concern now)

# Try and reduce payload over vehicle's rear axle where possible.  Reduce the length of hitch to receiver where that is possible to reduce rear axle loading & sway.

# Less weight in a heavy van is always preferable with transfer of that weight to the car over the axle providing you are not exceeding axle load limits.

FINAL PAYLOAD MASS OF CARAVAN - CALCS
Caravan Payload Weight at Weighbridge = 2,740kg
Minus Spare Tyre & Bracket (30kg) = 2,710kg  (whoever advised tyre + bracket was 30kg was spot on!)
Plus 20L Diesel Fuel (18.9kg) = 2,728.90

NEW CARAVAN PAYLOAD WEIGHT = 2,728.9kgs


PERCENTAGE VAN BALL WEIGHT AS A FUNCTION OF VANS PAYLOAD MASS
Percentage with Front Potable Tank EMPTY = (256.2/2728.9) x 100 = 9.388 = 9.34%  (acceptable with nose of van level or slightly lowered)

I am now to experiment with nose of caravan with my new van ball weight.  If it is not substantially lower I will obtain a longer drop shank.

Cheers guys, Tim

I think a better way of calculating the effect of tow ball weight of the axles is to consider Moments (if one remembers high school physics) about the front axle of the vehicle. The sum of the Moments = zero to be static.
Some people probably know this anyway. Others may not.

For Tim's case:

Use B = wheel base length = 2.85m for the Everest
Use C = hitch distance of tow ball from rear axle = 1.365m say, (my assumption from scaling on Tim's photos) adjust if required.
Use W = Tow Ball Weight = 220kg in this case from Tim's first trip to the weighbridge
Rb = back axle reaction = rear axle load amount from the tow ball weight.

So using the above:
Rb x B = W x (B + C) for Moments to be static

Hence
Rb = W x (B + C)/B

= 220 x ( 2.85+1.365)/2.85 kgs

= 325.4 kg. Which is similar to AWL's estimate 150% of loading from the tow ball to the back axle, in an earlier post.

Try a few cases, with wheel bases, hitch distances and tow ball/hitch weights

-- Edited by watsea on Tuesday 22nd of March 2022 12:19:12 PM

Watsea, it's fundamentally the same formula with a slightly different perspective. However yours does calculate the effect of leverage on the rear axle directly which is the focus here. Mine gives weight off the front, and the towball load needs to be added as a separate step.

Tim, you already have your tape measure readings from before the weighbridge. You also know what the weighbridge results were. So you can then use those measurements to see how much progress you are making as you move stuff around. Presumably you are going to weigh again once you think it's close.

It would also be helpful to know the Everest front and back weights without the van attached. With all the info you have, you will be able to tell how much difference it will make to rear axle load by moving your toothbrushes. It's been a useful refresher in physics for me too.

I posted the attached spreadsheet a few years ago when I first started trying to understand this myself.  It calculates front and rear axle weights.  Incidentally, these calculations are all built into the Load Calculator spreadsheet I posted yesterday.

There are two TABS in the spreadsheet.  The "Axle weights" TAB allows you to try your own values (See last line).  The "Calculations" TAB has the formula which I used.

Are We Lost wrote:

---

Watsea, it's fundamentally the same formula with a slightly different perspective. However yours does calculate the effect of leverage on the rear axle directly which is the focus here. Mine gives weight off the front, and the towball load needs to be added as a separate step.

Tim, you already have your tape measure readings from before the weighbridge. You also know what the weighbridge results were. So you can then use those measurements to see how much progress you are making as you move stuff around. Presumably you are going to weigh again once you think it's close.

It would also be helpful to know the Everest front and back weights without the van attached. With all the info you have, you will be able to tell how much difference it will make to rear axle load by moving your toothbrushes. It's been a useful refresher in physics for me too.

---

AWL,

I knew you were correct. Everything is ok.  I was just working from a different reference point. It is merely a matter of which point is selected to do the calculations about.  This is physics and in a static situation, and no matter what reference point, the sum of the applied Moments is zero and the sum of applied forces, that includes the reactions, is zero.

KevinJ,

I haven't downloaded your excel spreadsheet onto my main computer yet. I will interested to have a look.

Hoping Tim works his way through this issue for his rig.

Are We Lost wrote:

---

Watsea, it's fundamentally the same formula with a slightly different perspective. However yours does calculate the effect of leverage on the rear axle directly which is the focus here. Mine gives weight off the front, and the towball load needs to be added as a separate step.

Tim, you already have your tape measure readings from before the weighbridge. You also know what the weighbridge results were. So you can then use those measurements to see how much progress you are making as you move stuff around. Presumably you are going to weigh again once you think it's close.

It would also be helpful to know the Everest front and back weights without the van attached. With all the info you have, you will be able to tell how much difference it will make to rear axle load by moving your toothbrushes. It's been a useful refresher in physics for me too.

---

 To me, this all looks terribly complicated! Quick and easy way is to divide towball overhang (distance from rear axle to hitch point) by car's wheelbase. In most cases this gives a figure between 0.4 and 0 .5. This means that the weight transferred to the car's rear when the van is connected is between 1.4 (140%) and 1.5 (150%) times the towball weight. For example, if towball weight of 300kg was applied to a car with 3200mm wheelbase and 1400mm, the weight added to the car's rear axle would be 432kg +/-. (1400 divided by 3200 equals 0.4375. This means that the towball weight must be multiplied by 1.44  to get the figure for weight applied to car's rear axle ). Your formulae may well give the same result but this way works quickly for me.  Cheers

Yobarr - just applied your maths and it arrived at the same load mass on the rear axle.

Watsea & KevinJ - Apologies, I have been too busy making alterations to the WDH and pursuing the correct long shank today to make measurements. I will get there eventually however.

Per the long shank pursued, I did purchase a deeper shank made by Mr Hitches. For the record, Mr Hitches shanks are indeed compatible with the Fastway Equalizer 2 hitch coupling. Others wishing to pursue an E2 may like to know this since currently only the standard 3" and 8" shanks are available.

Fortunately I had my 3" E2 shank as a reference and went forearmed with a full tool set, tape, metal rule and spirit level. I had to travel 45 mins both ways and use expensive diesel so I was determined to make the trip as beneficial as I could!

The Mr Hitches shank I purchased was approximately 280mm long with 3 holes along the shank that slid into the receiver. The Ford Everest receiver (and I believe this applies to Ford Rangers also) can only accommodate a fairly short shank. That meant I could not access the 3rd hole to reduce the shank overhang from the receiver. I managed to have 40mm or so cut off the end ($30 charge) to access the 3rd hole. Guys, in doing so I was able to reduce the overhang by 50mm from my previous shank. I look forward to establishing the difference that makes to the weight over my rear axle.

The new shank also looks a lot closer to the rear of the car rather than a footy field away. I dropped the hitch coupling on the new shank to the 2nd hole with the top of the ball possibly as much as 25mm below the underside of top of receiver. Previously the ball was 15mm above this reference. So possibly a drop of 40mm in the ball relative to the underside of top of receiver. Those with an E2 hitch would be aware dropping a ball that much will probably require changes to the tensioner tie arms as well to ensure the right tension, but more particularly, that the tensioner bars remain horizontal to the caravan chassis with the tensioner head now lower. I removed a washer to bring the ball pitch more in line with the plane of the car's receiver.

Enough said, I placed the van on the ball and tensioned the E2-WDH to examine whether the caravan's nose was level or slightly lower (latter my preference). Indeed it was slightly lower and the tension appeared right studying the gap in the wheel arch of the front wheel. I studied the wheels of the 2 axles also. The rear had slightly more gap that the front axle and I was well pleased overall 

I took some pics of the caravan attached to the new hitch with WDH tensioned for your to peruse as well. Hope you agree with my above comments that the van nose now appears slightly down.

NEXT STAGE: Tomorrow morning I take measurements and establish the weight in theory over my back axle.

Cheer and thanks guys - Tim

P.S. Attached zip file accidentally.  Couldn't remove it.  Open only if you want high res pics! 

Terribly complicated? You just used the identical formula.

Multiply towball weight (F) by towball distance (y) and divide by wheelbase (x).

That gives you the weight lifted off the front wheels. Add towball weight if it's the load added to rear axle that you want. Watsea's has one more step in the formula but derives that directly.

The answer to your figures is 431kg.

Try it.

As I said before, it's an approximation, the same as yours. Use as an indicator.

Edit: Tim, you (and Watsea) posted while I was writing miine. Reducing the shank by 50mm will help a littlle but I was hoping for your sake you would achieve more. My calculator tells me only 4kg difference in axle load, but it's one more improvement in many. It will also help with resistance to sway. So although small, it improves two separate factors.

There is a lot of comment from some about how "dreadful" WDHs are because of that extra leverage. I would be interested to hear what the difference in measurement from the rear axle to towball is compared to the standard shank, and the weights of the appatus.

"Guys, in doing so I was able to reduce the overhang by 50mm from my previous shank. I look forward to establishing the difference that makes to the weight over my rear axle."

Out of curiosity, using the Load Calculator spreadsheet, I reduced the length of my shank by 50mm to see what the difference would be for my optimum setup.  It only improved the rear axle weight by 5kg which is less than I would have expected.  I would hope though that it would reduce the chance of sway by a more useful amount.  Either way, it can only help.

Hi Everyone

I have been attempting to determine my vehicle's rear axle weight now that I have new a satisfactory TBW after re-distributing the caravan's load.

I have the following findings which I would like others to scrutinise for any errors please.

Equalizer 2 WDH
Weight: 18.2kg
Centre Axle to Centre Towball Length: 1.470 metres

Standard Hitch (no drop shank)
Weight: 5.2kg
Centre Axle to Centre Towball Length: 1.325 metres

Other Variables
Ford Everest Wheelbase: 2.85 metres
Van TBW (rear potable tank full with water only): 256.2kg

Using formulae W2 = F * (y/x) + F supplied by AWL > to calculate load at rear axle.

Where:

W2 = weight lifted
F = tow ball weight
y = ball to axle distance
x = wheelbase

1) Vehicles Rear Axle Load with WDH: [ (256.2kg x 1.470m) / 2.85m] + 256.2kg = 388.345kg

2) Vehicles Rear Axle Load with Shortest Std Hitch Ford Everest can Accommodate: [ (256.2kg x 1.325m) / 2.85m] + 256.2kg = 375.31kg


FINDINGS

*Difference to vehicles rear axle load between WDH Hitch and STD HITCH - refer 1) & 2) above = 13.035kg

AXLE LOAD DIFFERENCE BETWEEN WDH AND STANDARD HITCH DUE TO WEIGHT AND DISTANCE FROM VEHICLES REAR AXLE

WITH E2 WEIGHT DISTRIBUTION HITCH

1) Ford Everests rear axle weight with payload (NO tension on WDH) + 388.345kg
= 1820kg + 388.35kg = 2,208.35kg

2) Ford Everests rear axle weight with payload (WITH tension on WDH) + 388.345kg
= 1640kg + 388.35kg =2,028.35kg

WITH STANDARD HITCH (NO DROP SHANK OR COUPLING FOR TENSIONER BARS)  - Assumption: Hitch weight at tow ball is amplified at rear axle by 150% (generous allowance) = 19.5kg

Ford Everests rear axle weight with payload (STD HITCH) + 375.31kg
= 1820kg 19.5kg (lighter hitch) + 375.31kg (shorter shank) = 2,175.81kg

CONCLUSION

These calculations suggest I am over my rear axle load limit of 1750kg by 278.35kg with WDH tensioned (i.e. 2028.35 1750).

According to the above maths, without a WDH hitch I am 147.46kg (say 147.5 kgs) worse off even with additional weight of WDH hitch.

Note also that Std Hitch used in comparison above had no drop shank to couple caravan to. Therefore, 147.5kg difference in axle load between the hitches compared above would in fact be LESS due to the increased weight of Std Hitch with drop shank (amplified at axle).


CAN OTHERS LOOK OVER MY MATHS AND CHECK I HAVE THE ABOVE CALCULATIONS RIGHT PLEASE?

HAVE I DOUBLE COUNTED TBW WEIGHT OF 1640KG IN POINT 2?  CARAVAN WAS COUPLED TO VEHICLE BUT WITH NO TENSION ON WDH WHEN REAR WHEELS WERE ON WEIGHBRIDGE.  SOME WEIGHT IS DISTRIUBUTED THROUGH DRAWBAR IS IT NOT??

SEEMS A LOT OF WT. ON THAT BACK AXLE FOR A RELATIVELY SMALL TBW OF 256.2KG AND NO MORE THAN 50KG OF GEAR OVER REAR AXLE IN CAR (LADEN CONDITION)!!

Below - refer pics of two hitches in this study. 

Cheers and thanks, Tim

thalls01 wrote:

---

Hi Everyone

I have been attempting to determine my vehicle's rear axle weight now that I have new a satisfactory TBW after re-distributing the caravan's load.

I have the following findings which I would like others to scrutinise for any errors please.

Equalizer 2 WDH
Weight: 18.2kg
Centre Axle to Centre Towball Length: 1.470 metres

Standard Hitch (no drop shank)
Weight: 5.2kg
Centre Axle to Centre Towball Length: 1.325 metres

Other Variables
Ford Everest Wheelbase: 2.85 metres
Van TBW (rear potable tank full with water only): 256.2kg

Using formulae W2 = F * (y/x) + F supplied by AWL > to calculate load at rear axle.

Where:

W2 = weight lifted
F = tow ball weight
y = ball to axle distance
x = wheelbase

1) Vehicles Rear Axle Load with WDH: [ (256.2kg x 1.470m) / 2.85m] + 256.2kg = 388.345kg

2) Vehicles Rear Axle Load with Shortest Std Hitch Ford Everest can Accommodate: [ (256.2kg x 1.325m) / 2.85m] + 256.2kg = 375.31kg


FINDINGS

*Difference to vehicles rear axle load between WDH Hitch and STD HITCH - refer 1) & 2) above = 13.035kg

AXLE LOAD DIFFERENCE BETWEEN WDH AND STANDARD HITCH DUE TO WEIGHT AND DISTANCE FROM VEHICLES REAR AXLE

WITH E2 WEIGHT DISTRIBUTION HITCH

1) Ford Everests rear axle weight with payload (NO tension on WDH) + 388.345kg
= 1820kg + 388.35kg = 2,208.35kg

2) Ford Everests rear axle weight with payload (WITH tension on WDH) + 388.345kg
= 1640kg + 388.35kg =2,028.35kg

WITH STANDARD HITCH (NO DROP SHANK OR COUPLING FOR TENSIONER BARS)  - Assumption: Hitch weight at tow ball is amplified at rear axle by 150% (generous allowance) = 19.5kg

Ford Everests rear axle weight with payload (STD HITCH) + 375.31kg
= 1820kg 19.5kg (lighter hitch) + 375.31kg (shorter shank) = 2,175.81kg

CONCLUSION

These calculations suggest I am over my rear axle load limit of 1750kg by 278.35kg with WDH tensioned (i.e. 2028.35 1750).

According to the above maths, without a WDH hitch I am 147.46kg (say 147.5 kgs) worse off even with additional weight of WDH hitch.

Note also that Std Hitch used in comparison above had no drop shank to couple caravan to. Therefore, 147.5kg difference in axle load between the hitches compared above would in fact be LESS due to the increased weight of Std Hitch with drop shank (amplified at axle).


CAN OTHERS LOOK OVER MY MATHS AND CHECK I HAVE THE ABOVE CALCULATIONS RIGHT PLEASE?

HAVE I DOUBLE COUNTED TBW WEIGHT OF 1640KG IN POINT 2?  CARAVAN WAS COUPLED TO VEHICLE BUT WITH NO TENSION ON WDH WHEN REAR WHEELS WERE ON WEIGHBRIDGE.  SOME WEIGHT IS DISTRIUBUTED THROUGH DRAWBAR IS IT NOT??

SEEMS A LOT OF WT. ON THAT BACK AXLE FOR A RELATIVELY SMALL TBW OF 256.2KG AND NO MORE THAN 50KG OF GEAR OVER REAR AXLE IN CAR (LADEN CONDITION)!!

Below - refer pics of two hitches in this study. 

Cheers and thanks, Tim

---

 Still no time to study your set up in detail, but notice that you have two shackles in your safety chains. This is illegal, and it would be wise to use hammerlocks to attach shackles to your towbar structure. This also would prevent your shackles being "borrowed" from your car. Just remember to remove the screw-in pins when not in use, as a shackle with no pin is as useless as no shackle at all! Cheers

thalls01 wrote:

---

WITH E2 WEIGHT DISTRIBUTION HITCH

1) Ford Everests rear axle weight with payload (NO tension on WDH) + 388.345kg
= 1820kg + 388.35kg = 2,208.35kg

2) Ford Everests rear axle weight with payload (WITH tension on WDH) + 388.345kg
= 1640kg + 388.35kg =2,028.35kg

WITH STANDARD HITCH (NO DROP SHANK OR COUPLING FOR TENSIONER BARS)  - Assumption: Hitch weight at tow ball is amplified at rear axle by 150% (generous allowance) = 19.5kg

Ford Everests rear axle weight with payload (STD HITCH) + 375.31kg
= 1820kg 19.5kg (lighter hitch) + 375.31kg (shorter shank) = 2,175.81kg

 

---

I believe the above calculations are incorrect. You have added the new calculated rear axle load to the weighbridge measured rear axle load. So you have virtually doubled it.

Unless I am mistaken, you don't have the Everest loads with it laden but disconnected. Sorry I did not include that step in the original weighbridge instructions.

I have estimated the rear axle weight using your (no WDH) figures of 1820, 220 towball, 50mm longer shank (1520mm). Using the formula it suggests the additional rear axle load to be 337kg. To estimate the disconnected rear axle load ....  1820 - 337 = 1483. Until you get an accurate weighbridge figure, I believe that should be the starting point, not the 1820kg you have used.

With 1470mm towball distance and 256kg towball weight the calculation suggests 388kg added. 1483 + 388 = 1871kg. That is before tensioning the WDH. Or 121kg overloaded. That is within the amount a WDH could manage, but it's tight. But you are changing distribution in the Everest as well, so that will change. And remember ..... it's a guide only.

Your photo shows you could have taken maybe another 40mm off the shank. Not much, but that 1470mm distance is significant. The difference in axle load would be negligible but if it were me, I would get it done assuming the new pin hole is not too close to the existing one. Is the shank in the receiver as far as it can go, or just where the hole happens to be?

The comparisons of WDH shank to standard were useful, but now that you have proven you need that WDH I suggest to drop those comparisons.

With what you want to carry, you really are on the limits for what the Everest can manage.

thalls01 wrote:

---

Yobarr - tanks for that advice. I gather from your statement that it is legal to use a hammerlock attached to a shackle but note 2 shackles in series - have I that correct? I gather a hammerlock with 2000lbs load rating with a breaking strain of 8000lbs would suffice?? Other matter - is it legal to use a hammerlock with an eye hook shackle in series with above rating? Thanks, Tim

---

 Hi Tim. You can use the hammerlock to attach a shackle to the towbar structure or to the end of the safety chain,or indeed in the middle to simply lengthen the chain, but you cannot have more than one shackle in the length of the chain. Not able to advise on hammerlock ratings, as not at home, but any reputable lifting equipment business could help you. Once again I would like to congratulate you on being so responsible with your weights, but still I am unable to devote the necessary time to research your original request. Seems you have had lots of good advice so far from interested members, but, to be honest, at this stage things are not looking good for you. Let's hope that that unresearched opinion is proven incorrect! Cheers.

Hi Tim, My suggestion is to plug all the numbers into the spreadsheet an let it do the maths for you.

Watsea and Others - FYI - Hammerlock sizes, Use and Australian Standards

G80 Hammerlock Safety Chain Connector
G80 Hammerlock connector to suit galvanised 8mm, 10mm and 13mm safety chain. Use a hammerlock to join your trailer chain or to lengthen your chain.

The safety chain is connected to the caravan or trailer chassis rail by a hammerlock connector.

8mm - 2t Hammerlock
10mm - 3.15t Hammerlock
13mm - 5.3t Hammerlock
The trailer chain hammerlocks above are not interchangeable with different size chain. For example, a 2t Hammerlock will not fit a 10mm chain.

Hammerlocks fit:
Safety Chain Holders on steel chassis rails
Safety Chain Holders bolted to aluminium chassis rails.

Is your trailer or caravan chain too short?

The solution:
Cut the trailer chain from your chassis rail, leaving one welded link on the chassis.
Install a new piece of rated galvanised 10mm longer chain. This chain is 64cm long; click here.
Connect the hammerlock to the new chain and the welded link on the chassis rail.

What you cannot do:
Join shackles until you reach the desired length.
Insert un-rated links
Galvanised chains and shackles are illegal on all trailers OVER 3.5t.

It is essential to remember:
No chain welding over 2.5t
No welding chain links below the chassis rails.
Note: The welded chain link is not rated. The welded chain is considered a link or a chain holder.

Trailers up to 2.5 tonnes ATM must have at least one safety chain complying with AS 4177.4 - 1994 (Trailer and light trailer towing components Safety chains up to 3.5 tonnes capacity), or as amended from time to time. This standard allows for steel safety chains by the following:

Up to 1.0 tonne, a chain size of 6.3 mm;
Up to 1.6 tonnes, a chain size of 8 mm;
Up to 2.5 tonnes, a chain size of 10 mm.
Trailers over 2.5 and up to 3.5 tonnes ATM must have two safety chains complying with AS4177.4 - 1994 or as amended from time to time. This standard allows for steel safety chains by the following:

Up to 3.5 tonnes, a chain size of 13 mm.

The fitting of safety chains to trailers with a Gross Trailer Mass (GTM) greater than 2.0 tonnes and fitted with a brake system that automatically applies if the caravan becomes detached from the towing vehicle, is optional.

However, trailers in excess of 3.5 tonnes ATM, all medium and heavy category pig trailers with rigid drawbars, any other trailers without breakaway brakes and all fixed and inflexible pig trailers with a GTM higher than 2.5 tonnes and fitted with automatic pin-type couplings, must be equipped with safety chains in accordance with the information contained in AIS Information Sheet 12(b) Safety Chain Requirements.
Cheers, Tim

-- Edited by thalls01 on Wednesday 23rd of March 2022 10:13:02 PM

P.S.  Should have acknowledged source of above hammerlock and safety chain information as 'Couplemate AU' - https://www.couplemate.com.au/safety-chains-dee-shackles/hammerlock-to-suit-galvanised-safety-chain/

thalls01 wrote:

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watsea - I have ordered 2 x 5.3 tonne working load hammerlocks online this afternoon. Their diameter is 13mm.

The 3.2 tonne equivalents have a breaking load of 8 tonne so the 5.3 tonne hammerlocks on order should more than do the job!


Looking forward to plugging the numbers into KevinJ's sophisticated spreadsheet tomorrow after I have the vehicle's weights for loaded and unloaded conditions (more weights is better). I believe more Nomads should be using KevinJ's 'Load Calculator' since it has 40,000 codes of Visual Basic unseen in the background to support the calculations and allows members to track ball weight and axle load as one distributes weight in the vehicle or trailer/van in tow each expedition.

KevinJ - in this topic has also shared his tyre calculator. I will be using that to plug in my dynamic weights each trip to calculate the ideal PSI for the car and caravan's tyres. Thanks Kevin for sharing the spreadsheets!


With thanks, Tim

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 Correction, 40,000 should read 1,000