i just had my rig put over the weigh bridge whilst away on a road trip. When it came to toe ball mass the operator did not want me to unhitch. Instead he had me raise the jockey wheel so high it was lifting the back of the car quite considerably. Surely this must give a false TBM reading. As a result I am a little over on ATM but considerably over on TBM. Does this sound correct or should I return and ask for a do over and this time unhitch.
Dougwe said
06:03 PM Feb 12, 2020
See if there is a 'go weigh' weighbridge close by. You do it all yourself. You need a credit card.
They are usually at big BP centres.
yobarr said
07:03 PM Feb 12, 2020
ConsumerMan wrote:
i just had my rig put over the weigh bridge whilst away on a road trip. When it came to toe ball mass the operator did not want me to unhitch. Instead he had me raise the jockey wheel so high it was lifting the back of the car quite considerably. Surely this must give a false TBM reading. As a result I am a little over on ATM but considerably over on TBM. Does this sound correct or should I return and ask for a do over and this time unhitch.
Hi Alan....absolutely you must return,driving over the weighbridge until only the van wheels are on the weighbridge,but the jockey wheel will still be on the bridge when you unhook the van.First take the GTM (weight on van wheels) then lower the jockey wheel,unhook the van,and move forward. When you take the next reading (ATM) you must be sure that the drawbar is at the same height that it was at when the van was connected to the car.ATM minus GTM gives towball weight,(Obviously) but always remember that the extra weight applied to your car's rear axle is much greater than the actual towball weight....anywhere from 135% to well over 155% more,depending on the car's wheelbase and the TBO (towball overhang,or distance from car's rear axle to hitch point.) One of the worst figures comes from an LC200,while a Ford Ranger has one of the best.A WDH makes the figures worse,while one popular type of hitch makes a bad situation even worse.Cheers
P.S Your weighbridge operator is not alone as I recently had a run-in with one here in Brisbane.He was adamant that his methods were correct,and he told me he had "....been doing this for 30 years.....",but after we had "words" and I took time to point out where he was going wrong,he now has a completely new,and correct,understanding of the correct procedure.Good luck.Cheers
Cupie said
08:25 PM Feb 12, 2020
Dougwe wrote:
See if there is a 'go weigh' weighbridge close by. You do it all yourself. You need a credit card.
They are usually at big BP centres.
Had a look at their locations. Seems like they are a Victorian thing.
Good idea though. Wish that there were some here in SEQ.
Brenda and Alan said
09:45 PM Feb 12, 2020
Yobarr if you unhook the van to take the ATM it doesn't matter what height your tow ball is at as it will have no effect on what weight the bridge sees. ATM is ATM.
Alan
-- Edited by Brenda and Alan on Wednesday 12th of February 2020 09:45:58 PM
montie said
10:35 PM Feb 12, 2020
Drive the tug only onto weighbridge with van hooked and record that measured weight.
Without moving the tug unhook the van and weigh again.
The difference is your ball weight.
You can do the same exercise with the van.
ConsumerMan said
03:59 AM Feb 13, 2020
The weigh bridge I used was not one big scales. It had a large pad for measuring axle weight, and forward there was a smaller pad, about 750x500mm, for measuring ball weight. So I am not going crazy, everybody agrees that the operator should of had me unhitch? Looks like I am returning for an argument.
SouthernComfort said
08:01 AM Feb 13, 2020
I agree with Dougwe, the 'go weigh' ones at BP are the best, luckily we have one nearby. The platform is in 4 end to end sections with guide lights to tell you how to position the rig. Then it will measure ATM, ball weight, front and rear vehicle axles individually. Van must be uncoupled for the ball weight. CC payment, printed ticket issued showing date and all measurements.
Dougwe said
08:46 AM Feb 13, 2020
Hi Graham, hope you and Carol are well?
You got me looking at their website too and you are correct, it does look VIC only. If they prove successful they might start up in other states. Wouldn't be a cheap thing to set up but quick set up though.
One thing I liked was you can have the details printed as well as emailed to you or someone else. It came in handy when I changed insurance companies late 2019. I just emailed it to them, easy.
yobarr said
09:00 AM Feb 13, 2020
Brenda and Alan wrote:
Yobarr if you unhook the van to take the ATM it doesn't matter what height your tow ball is at as it will have no effect on what weight the bridge sees. ATM is ATM.
Alan
-- Edited by Brenda and Alan on Wednesday 12th of February 2020 09:45:58 PM
ATM is indeed ATM,and it is made up of GTM plus towball weight.The reason that I said that the drawbar van must be at the same level as it was when connected is that towball weight changes as the drawbar is raised or lowered,particularly on non-loadsharing axle groups.To illustrate,if you were to reverse your caravan to the edge of a cliff,unhook,and raise the drawbar until the van chassis was at 45 degrees to the ground,towball weight would be minimal,but GTM would go through the roof.....ATM would stay the same.THAT is why,to get accurate readings for towball and GTM,the drawbar should always be at the same level. The OP seems to be looking to get an accurate towball weight? Cheers
montie said
09:05 AM Feb 13, 2020
ConsumerMan wrote:
The weigh bridge I used was not one big scales. It had a large pad for measuring axle weight, and forward there was a smaller pad, about 750x500mm, for measuring ball weight. So I am not going crazy, everybody agrees that the operator should of had me unhitch? Looks like I am returning for an argument.
If the weighbridge does not allow you to calculate your ball weight there is only one other accurate method of doing so.....measure at the coupling with a level unhitched van.
You cannot measure the ball weight of a hitched van.
iana said
09:32 AM Feb 13, 2020
Far too much emphasis is placed on tow ball weight, all positive tow ball weight does is ensure the center of gravity of the towed trailer is forward of the axle center. The tow ball weight as Yobar says, changes all the time, when going up or down hills, accelerating, decelerating etc.
The main weight as far as I am concerned is the combined weight of the tow vehicle and the towed trailer, if that's too high, you are over weight, no matter what else you weigh. If your combined weight is OK, then you need to check the weights of the van hitched and the tow vehicle hitched. If one is too high, weight needs to be transferred.
The tow ball weight is quoted at 10% but that is not a hard and fast rule, if you can borrow a set of bathroom scales, that will get that weight. But aiming between 6 - 10 (or higher) is OK.
Nevd said
11:36 AM Feb 13, 2020
Tow ball weight must be taken into account for the tow vehicle's GVM. There has been plenty of discussion about exceeding GVM because of the combined effect of accessories, fuel, passengers and their junk, dogs, and gear carried. TBW is included, so a 300 - 350 kg weight is an impost on many vehicle's GVM.
Consumerman, have you considered a mobile caravan weighing service? There are several in SEQ, and their scales are more accurate than weighbridges. The one I used had race car scales accurate within 1kg. Definitely worth the money I feel.
Radar said
01:14 PM Feb 13, 2020
My thoughts there are to much emphasis is placed on this magic tow ball weights.
I personally feel after obtaining your "gross combination weight" which is the most important and its with in the car and trailer regulation.
The next main one is the rear axle weight of the towing vehicle which is most important in the balance of the set up, a tow vehicle with a trailer dropped on is instantly taking weight of the front wheels with the see saw affect.
With our twin cab Ute, I can get to about 2900 out of my 3020 kg GVM before I start over loading the rear axle with our 2750 kg caravan on with approx 270 kg ball weight and the heavious weighed gross combination weight of about 5600 kgs and our car has 60020GCM which is not normally achievable with a tow ball towed trailer.
It is not practicable placing weight forward of the drive axle on most cars.
iana said
01:40 PM Feb 13, 2020
ConsumerMan has not told us what vehicle he tows with nor the size of the van.
The gross combined mass is a combination of the maximum allowed mass of the trailer and the maximum allowed mass of the vehicle. This weight is set by the manufacturer of the tow vehicle, and shouldn't be exceeded. I know, I know, but for this thread, lets just say the manufacturer states the GCM.
montie said
03:13 PM Feb 13, 2020
I think the OP's question was about towball mass and how to weigh it, rather than GCM.
Incorrect towball download will result in an unstable rig so it is important that it is maintained at around 10% of the loaded van for safety reasons.
GCM is a different topic altogether.
SouthernComfort said
05:10 PM Feb 13, 2020
montie wrote:
I think the OP's question was about towball mass and how to weigh it, rather than GCM. Incorrect towball download will result in an unstable rig so it is important that it is maintained at around 10% of the loaded van for safety reasons.
GCM is a different topic altogether.
"10% or close to it when the van is static, unhitched, and dead level". That's what my service workshop has always told me. Presumably any variation to the static measurement caused by driving undulations (which you can't control) would be considered tolerable if the static weight starts out correctly.
Brenda and Alan said
06:03 PM Feb 13, 2020
Yobarr your explanation is still Irish. Irrespective of the height of tow ball, tow ball weight plus weight on the wheels equals ATM. If you stood the caravan up on its end tow ball weight is zero but the scales still give the same ATM.
Alan
yobarr said
07:01 PM Feb 13, 2020
Brenda and Alan wrote:
Yobarr your explanation is still Irish. Irrespective of the height of tow ball, tow ball weight plus weight on the wheels equals ATM. If you stood the caravan up on its end tow ball weight is zero but the scales still give the same ATM.
Alan
Where have I ever suggested that ATM is anything but towball weight plus GTM? Your comment about standing the van on its end is an extension of my post about having the drawbar at 45 degrees to the ground. I'm sorry,but I don't understand your suggestion that my explanation is Irish,as all the OP was asking was for help with measuring his towball weight.Both Montie and I made suggestions in an effort to assist.When measuring ball weight,the drawbar MUST be the same distance above the ground as it was when the van was connected to the van.Cheers.
montie said
07:36 PM Feb 13, 2020
yobarr wrote:
Brenda and Alan wrote:
Yobarr your explanation is still Irish. Irrespective of the height of tow ball, tow ball weight plus weight on the wheels equals ATM. If you stood the caravan up on its end tow ball weight is zero but the scales still give the same ATM.
Alan
Where have I ever suggested that ATM is anything but towball weight plus GTM? Your comment about standing the van on its end is an extension of my post about having the drawbar at 45 degrees to the ground. I'm sorry,but I don't understand your suggestion that my explanation is Irish,as all the OP was asking was for help with measuring his towball weight.Both Montie and I made suggestions in an effort to assist.When measuring ball weight,the drawbar MUST be the same distance above the ground as it was when the van was connected to the van.Cheers.
Ah...good 'ol Paddy the Irishman!
He never seems to get it right! Keep trying Paddy!
Brenda and Alan said
09:56 PM Feb 13, 2020
Yobarr i'm very sorry but your post was about measuring ATM not tow ball weight.
Alan
Brenda and Alan said
09:58 PM Feb 13, 2020
Yobarr i'm very sorry but your post was about measuring ATM not tow ball weight. Re read your original post .
Alan
yobarr said
10:07 PM Feb 13, 2020
Brenda and Alan wrote:
Yobarr i'm very sorry but your post was about measuring ATM not tow ball weight.
Alan
Without wanting to confuse you too much,my post was structured to give advice on how to accuratelymeasure tow ball weight....nothing else.Cheers
-- Edited by yobarr on Friday 14th of February 2020 12:14:57 PM
Rob Driver said
09:31 AM Feb 14, 2020
Well this will probably be another topic that illustrates exactly why members are not contributing any more on this forum.
I ask are all the highlighted words and the I AM attitude really necessary.
The question of contribution was only asked a few days ago in this topic.
i just had my rig put over the weigh bridge whilst away on a road trip. When it came to toe ball mass the operator did not want me to unhitch. Instead he had me raise the jockey wheel so high it was lifting the back of the car quite considerably. Surely this must give a false TBM reading. As a result I am a little over on ATM but considerably over on TBM. Does this sound correct or should I return and ask for a do over and this time unhitch.
The weighman is wrong, his method is giving a false reading on his scales.
The weighbridge we mostly use weighs the car twice, the first time with the caravan on and second time without the caravan.
Takes the weight from the other weight and this gives you a good reading of the ball weight.
Brenda and Alan said
03:13 PM Feb 14, 2020
Yobarr here is the sentence which is wrong
"When you take the next reading (ATM) you must be sure that the drawbar is at the same height that it was at when the van was connected to the car."
where here did you refer to tow ball weight. Enough said.
Alan
montie said
03:22 PM Feb 14, 2020
Brenda and Alan wrote:
Yobarr here is the sentence which is wrong
"When you take the next reading (ATM) you must be sure that the drawbar is at the same height that it was at when the van was connected to the car."
where here did you refer to tow ball weight. Enough said.
Alan
Alan,
You must weigh the van hitched (GTM) and then weigh unhitched (ATM) the difference being the calculated ball weight. All this without moving the van and ensuring that it is level.
Basically the difference between the hitched and unhitched weights is the ball weight based on the formula ATM - GTM = Ball weight.
You can, as I suggested in an earlier post, do the same exercise with the tug.
-- Edited by montie on Friday 14th of February 2020 03:25:24 PM
yobarr said
04:24 PM Feb 14, 2020
Brenda and Alan wrote:
Yobarr here is the sentence which is wrong
"When you take the next reading (ATM) you must be sure that the drawbar is at the same height that it was at when the van was connected to the car."
where here did you refer to tow ball weight. Enough said.
Alan
Are you for real? The reason for recording the ATM is that you need the ATM in order to calculate the towball weight if you already have taken the GTM,as ATM is the sum of GTM plus towball weight.And the drawbar must be at the same height for each reading,as I have already posted.I sincerely hope that this helps you to understand? Cheers
i just had my rig put over the weigh bridge whilst away on a road trip. When it came to toe ball mass the operator did not want me to unhitch. Instead he had me raise the jockey wheel so high it was lifting the back of the car quite considerably. Surely this must give a false TBM reading. As a result I am a little over on ATM but considerably over on TBM. Does this sound correct or should I return and ask for a do over and this time unhitch.
They are usually at big BP centres.
Hi Alan....absolutely you must return,driving over the weighbridge until only the van wheels are on the weighbridge,but the jockey wheel will still be on the bridge when you unhook the van.First take the GTM (weight on van wheels) then lower the jockey wheel,unhook the van,and move forward. When you take the next reading (ATM) you must be sure that the drawbar is at the same height that it was at when the van was connected to the car.ATM minus GTM gives towball weight,(Obviously) but always remember that the extra weight applied to your car's rear axle is much greater than the actual towball weight....anywhere from 135% to well over 155% more,depending on the car's wheelbase and the TBO (towball overhang,or distance from car's rear axle to hitch point.) One of the worst figures comes from an LC200,while a Ford Ranger has one of the best.A WDH makes the figures worse,while one popular type of hitch makes a bad situation even worse.Cheers
P.S Your weighbridge operator is not alone as I recently had a run-in with one here in Brisbane.He was adamant that his methods were correct,and he told me he had "....been doing this for 30 years.....",but after we had "words" and I took time to point out where he was going wrong,he now has a completely new,and correct,understanding of the correct procedure.Good luck.Cheers
Had a look at their locations. Seems like they are a Victorian thing.
Good idea though. Wish that there were some here in SEQ.
Yobarr if you unhook the van to take the ATM it doesn't matter what height your tow ball is at as it will have no effect on what weight the bridge sees. ATM is ATM.
Alan
-- Edited by Brenda and Alan on Wednesday 12th of February 2020 09:45:58 PM
Without moving the tug unhook the van and weigh again.
The difference is your ball weight.
You can do the same exercise with the van.
You got me looking at their website too and you are correct, it does look VIC only. If they prove successful they might start up in other states. Wouldn't be a cheap thing to set up but quick set up though.
One thing I liked was you can have the details printed as well as emailed to you or someone else. It came in handy when I changed insurance companies late 2019. I just emailed it to them, easy.
ATM is indeed ATM,and it is made up of GTM plus towball weight.The reason that I said that the drawbar van must be at the same level as it was when connected is that towball weight changes as the drawbar is raised or lowered,particularly on non-loadsharing axle groups.To illustrate,if you were to reverse your caravan to the edge of a cliff,unhook,and raise the drawbar until the van chassis was at 45 degrees to the ground,towball weight would be minimal,but GTM would go through the roof.....ATM would stay the same.THAT is why,to get accurate readings for towball and GTM,the drawbar should always be at the same level. The OP seems to be looking to get an accurate towball weight? Cheers
If the weighbridge does not allow you to calculate your ball weight there is only one other accurate method of doing so.....measure at the coupling with a level unhitched van.
You cannot measure the ball weight of a hitched van.
The main weight as far as I am concerned is the combined weight of the tow vehicle and the towed trailer, if that's too high, you are over weight, no matter what else you weigh. If your combined weight is OK, then you need to check the weights of the van hitched and the tow vehicle hitched. If one is too high, weight needs to be transferred.
The tow ball weight is quoted at 10% but that is not a hard and fast rule, if you can borrow a set of bathroom scales, that will get that weight. But aiming between 6 - 10 (or higher) is OK.
Tow ball weight must be taken into account for the tow vehicle's GVM. There has been plenty of discussion about exceeding GVM because of the combined effect of accessories, fuel, passengers and their junk, dogs, and gear carried. TBW is included, so a 300 - 350 kg weight is an impost on many vehicle's GVM.
Consumerman, have you considered a mobile caravan weighing service? There are several in SEQ, and their scales are more accurate than weighbridges. The one I used had race car scales accurate within 1kg. Definitely worth the money I feel.
My thoughts there are to much emphasis is placed on this magic tow ball weights.
I personally feel after obtaining your "gross combination weight" which is the most important and its with in the car and trailer regulation.
The next main one is the rear axle weight of the towing vehicle which is most important in the balance of the set up, a tow vehicle with a trailer dropped on is instantly taking weight of the front wheels with the see saw affect.
With our twin cab Ute, I can get to about 2900 out of my 3020 kg GVM before I start over loading the rear axle with our 2750 kg caravan on with approx 270 kg ball weight and the heavious weighed gross combination weight of about 5600 kgs and our car has 60020GCM which is not normally achievable with a tow ball towed trailer.
It is not practicable placing weight forward of the drive axle on most cars.
The gross combined mass is a combination of the maximum allowed mass of the trailer and the maximum allowed mass of the vehicle. This weight is set by the manufacturer of the tow vehicle, and shouldn't be exceeded. I know, I know, but for this thread, lets just say the manufacturer states the GCM.
Incorrect towball download will result in an unstable rig so it is important that it is maintained at around 10% of the loaded van for safety reasons.
GCM is a different topic altogether.
"10% or close to it when the van is static, unhitched, and dead level". That's what my service workshop has always told me. Presumably any variation to the static measurement caused by driving undulations (which you can't control) would be considered tolerable if the static weight starts out correctly.
Yobarr your explanation is still Irish. Irrespective of the height of tow ball, tow ball weight plus weight on the wheels equals ATM. If you stood the caravan up on its end tow ball weight is zero but the scales still give the same ATM.
Alan
Where have I ever suggested that ATM is anything but towball weight plus GTM? Your comment about standing the van on its end is an extension of my post about having the drawbar at 45 degrees to the ground. I'm sorry,but I don't understand your suggestion that my explanation is Irish,as all the OP was asking was for help with measuring his towball weight.Both Montie and I made suggestions in an effort to assist.When measuring ball weight,the drawbar MUST be the same distance above the ground as it was when the van was connected to the van.Cheers.
Ah...good 'ol Paddy the Irishman!
He never seems to get it right! Keep trying Paddy!
Yobarr i'm very sorry but your post was about measuring ATM not tow ball weight.
Alan
Yobarr i'm very sorry but your post was about measuring ATM not tow ball weight. Re read your original post .
Alan
Without wanting to confuse you too much,my post was structured to give advice on how to accurately measure tow ball weight....nothing else.Cheers
-- Edited by yobarr on Friday 14th of February 2020 12:14:57 PM
I ask are all the highlighted words and the I AM attitude really necessary.
The question of contribution was only asked a few days ago in this topic.
thegreynomads.activeboard.com/t66307985/soooooooo-quiet-whats-wrong/
Regards
Angie
The weighman is wrong, his method is giving a false reading on his scales.
The weighbridge we mostly use weighs the car twice, the first time with the caravan on and second time without the caravan.
Takes the weight from the other weight and this gives you a good reading of the ball weight.
Yobarr here is the sentence which is wrong
"When you take the next reading (ATM) you must be sure that the drawbar is at the same height that it was at when the van was connected to the car."
where here did you refer to tow ball weight. Enough said.
Alan
Alan,
You must weigh the van hitched (GTM) and then weigh unhitched (ATM) the difference being the calculated ball weight. All this without moving the van and ensuring that it is level.
Basically the difference between the hitched and unhitched weights is the ball weight based on the formula ATM - GTM = Ball weight.
You can, as I suggested in an earlier post, do the same exercise with the tug.
-- Edited by montie on Friday 14th of February 2020 03:25:24 PM
Are you for real? The reason for recording the ATM is that you need the ATM in order to calculate the towball weight if you already have taken the GTM,as ATM is the sum of GTM plus towball weight.And the drawbar must be at the same height for each reading,as I have already posted.I sincerely hope that this helps you to understand? Cheers