Dangerous nose weight guages

[Steve L]

I've just had a lucky escape while using a spring loaded nose weight guage.

I placed the guage under the hitch but not inside the ball cup of the coupling. As I wound the hitch down to weigh the nose weight I though it was reading too heavey and took a look, just as I was reading 150Kgs!! It slipped off the hitch.

The piston hit me in the mouth putting a split in my lip big enough to park a pencil in and loosening three teeth. Another part of the guage hit my eyebrow giving me a shiner.

Believe me I know just how lucky I was not to break my jaw or even kill myself, and the fat lip complete with stiches inside and out is a let off!!

So a little advise from the wise in hindsight, ALWAYS LOCATE THE GUAGE IN THE PROPER PLACE IN THE COUPLING. unless you want to know what a 150Kg upper cut feels like.

Just thought I'd share this escapade with you all to enlighten you on a simple safety lesson learned the hard way.

Steve.

 

[mike_5041102]

Thanks very much for that Steve. I've often wondered what was the correct location for the nose guage, as far as I remenber mine didnt come with any instructions.

 

[Icemaker]

very good advice as my gauge had no instructions with it either. I have also just found out that my gauge is 20 kgs out on its measurement, i weighed the van with the gauge and was surprised to see it showing 95 kgs with nothing in the front box, i got the bathroom scales and a piece of wood (the old fashioned way)and checked again to find my noseweight at 75 kgs. the gauge i have is the commonly found red square plastic type with a sliding scale, its now in the bin.

 

[mike_5041102]

It doesn't need to go in the bin, just re-calibrate it by changing the numbers (95 = 75)

 

[Icemaker]

unfortunately it wasnt possible to do that Mike as i need 85 kgs on my hitch and the gauge only went to 100 kgs.

 

[lyn_5041588]

very good advice as my gauge had no instructions with it either. I have also just found out that my gauge is 20 kgs out on its measurement, i weighed the van with the gauge and was surprised to see it showing 95 kgs with nothing in the front box, i got the bathroom scales and a piece of wood (the old fashioned way)and checked again to find my noseweight at 75 kgs. the gauge i have is the commonly found red square plastic type with a sliding scale, its now in the bin.

we also had the same problem 20kg out, we took the one we had back to the shop and eventually they gave us our money back, now it's back to the bathroom scales.

 

[Ian_5084692]

This is an interesting one. I purchased one of these guages and I have fnd it very difficult to get it to sit comfortably on the ball and correctly located in the hitch. I tow with a Galaxy which has a maximum tow ball weight of 85KG. The first tme I used the guage it read in excess of 100KG. I was horrified and re-distributed everything but the kitchen sink form the front box.

Are people telling me that these guages appear to be some 20 KGs out?

Ian

 

[ProfJohnL]

Hello Ian,

Does teh box or instructions state the potential error allowance of the product?

If not take it to trading standards.

 

[mike_5041102]

Ian, mine was 20 kg too low. this doesn't mean they will all be out by that amount. I've heard of others being anything from a few kgs to 25kg out. You dont know what the thing is measuring until you can check it against something else. A good check is compare with the wife's bathroom scales, but first make sure these are accurate. How? Easy, take yourself down to the chemist if you can find one with a large weighing machine. Weigh yourself, go home and check your weight on the bathroom scales. Nw you know the error of the bathrooom scales. Now check towball weight with the noseweight gauge and do again using the bathroom scales.

 

[ProfJohnL]

Hello Mike,

There are three problems with your method of gauging accuracy, by only using a single test load you cannot predict the correction required at any other load.

There are three basic types of error for such devices.

1. "Offset error" this is where you need to add or subtract a CONSTANT correction to the measured result. This is the type you describe.

2. ""Gradient error" this is where you need to multiply the measured figure by a scaling factor.

3. "Non Linear Errors" where the system does not extend or compress in direct proportion to the load applied.

To use your system, you need to try many different sample loads and then map results. It is the possible to interpolate between your test loads.

The best way is to purchase a calibrated device and to maintain it within calibration.

Any device for weighing when it is used for the assessment of a load where it may have legal or safety implications should be sold in a calibrated form with a statement of uncertainty.

You can bet that the police would not get away with a prosecuting if their equipment was found to be either uncalibrated or had a calibration records that showed significant drift with use or time.

 

[mike_5041102]

John, can you give an indication of what a calibrated gauge will cost and who sells them?

 

[Lutz]

Do you really need a calibrated guage? If you take a bit of care using standard bathroom scales, you should be as accurate as you need be. The outfit is not going to handle any less stable at 73kg than at 75kg and I've never heard of police checking noseweights unless it's plainly obvious that they are way off.

 

[ProfJohnL]

John, can you give an indication of what a calibrated gauge will cost and who sells them?

Hello Mike,

This comment is posted after Lutz's response.

The answer is I don't know who if anyone provides such an accurate gauge, but I was using this oppertunity to show how many loopholes there are in some of the devises supplied.

I do still maintain that if you are sold a graduated guage, there should be some indication of it inaccuracy so users can make informed decisions. Ask your supplier how accurate it is. Its my guess that a device with a 20Kg error is not really suitable for this application, so why is it being sold?

 

[mike_5041102]

Hello Mike,

This comment is posted after Lutz's response.

The answer is I don't know who if anyone provides such an accurate gauge, but I was using this oppertunity to show how many loopholes there are in some of the devises supplied.

I do still maintain that if you are sold a graduated guage, there should be some indication of it inaccuracy so users can make informed decisions. Ask your supplier how accurate it is. Its my guess that a device with a 20Kg error is not really suitable for this application, so why is it being sold?

Agree with you there John, these things are like tyre pressure gauges, sold so someone can get rich without consideration of safety issues.

 

[giovanni_5060838]

this is worrying,i mean how inaccurate they can be. but are

bathroom scales any better?

i thought the towball weight was more to do with what the cars

floor can support safely, before it becomes stressed and dangerous, am i wrong?

 

[Lutz]

What you think is not wrong, Giovanni, but it is only part of the story.

The car and towbar manufacturers must verify by test that their products are capable of meeting certain levels of durability (2 million cycles under a dynamic load which is based on the specified max. noseweight and towload). This applies not only to the towbar itself but also the vehicle underbody. However, in addition, the car manufacturer must also prove that the car is otherwise technically capable of handling the towload, i.e. the brakes, engine cooling, clutch, vehicle handling, etc. are up to meeting requirements.

 

[giovanni_5060838]

my other car has a towbar weight of only 60 kgs, engine, brakes,

and weight are more than ok for towing what i own and more.

but i used the vectra est, because its towball weight was 75kgs

and on a cheap nose weight gauge, it showed 80 kgs, which made

it near impossible for me to get it down to 60kgs,and bearing in mind i read that you should always have at least 50kgs, thought the best solution was the vecra.

but from what i am reading here, the nose weight gauge could

be between 10 and 20kgs out, and to add to that, i could properbly get away with a towbar weight of 65kgs on my car that

advises me its limited to 60kgs, or is this ill advised.

 

[Lutz]

I wouldn't worry about being off by 5kg. As I've written further up this thread, just make sure you don't exceed the maximum permissible figure but the stability of your outfit won't suffer noticeably if you're 5kg down.

 

[Colinn]

Guys, can u advise me. Is it reasonable to expect that the weight measured by a gauge under the towball will be the same as bathroom scales under the jockey wheel, bearing in mind that the ball/hitch is further out? Is it near enough so as to make no matter?

Secondly, will the measurement be accurate if the caravan is set level (ie, side to side and front to rear) but on a slight upwards slope. Or must the ground be dead level too to get an accurate reading?

Hope I've explained that well enough.

(You'll see under a separate Topic that I am a beginner and have a noseweight problem!!)

Colin

 

[Lutz]

How far off the method using bathroom scales under the lockey wheel is depends how far behind the coupling the jockey wheel is located and how long the caravan is. The larger the distance between the coupling and the jockey wheel and the shorter the caravan, the bigger the inaccuracy. A reading taken under the jockey wheel will always be higher than the actual noseweight.

There's nothing wrong with using bathroom scales but for an accurate figure you should use a piece of wood of suitable length to support the coupling and measure the noseweight there. The length of the piece of wood must be cut to ensure the same height of the coupling as when the caravan is hitched up to the car and all measurements must be carried out on level ground.

 

[Colinn]

How far off the method using bathroom scales under the lockey wheel is depends how far behind the coupling the jockey wheel is located and how long the caravan is. The larger the distance between the coupling and the jockey wheel and the shorter the caravan, the bigger the inaccuracy. A reading taken under the jockey wheel will always be higher than the actual noseweight.

There's nothing wrong with using bathroom scales but for an accurate figure you should use a piece of wood of suitable length to support the coupling and measure the noseweight there. The length of the piece of wood must be cut to ensure the same height of the coupling as when the caravan is hitched up to the car and all measurements must be carried out on level ground.

Thanks Lutz, that's very helpful. It's back to the drawing board for me...!!