Wheel weights - what is their function?

[AdrianNPMajor]

I wonder if members could educate me re the need for/functions of wheel weights, both front and rear. I have a NP Super Major with 19" pressed steel wheels. The manual seems to indicate that the front wheel weights are more important when ploughing than rear wheel weights. I'm trying to get my head around the physics and the theory.

Many thanks in advance for any info.

Adrian

[fenhayman]

Adrian I will try to help. When ploughing or carrying out any operation where wheelslip could be a problem weight is added to the rear of the tractor. Tyres (inner tubes) can be filled with saline and weights added to the rear rwheels. Extra weight is particularly useful when ploughing stubble or grassland where the tyres are inclined to slip on a hard surface.
In terms of axtra weight for grip, with my limited knowledge I would say that extra weight on the front of a wheeled tractor is an incumberance unless the front wheels are powered (4 wheel drive) or the tractor is a tracklayer.

When using a heavy reversible plough front wheel weights are sometimes necessary to counteract the weight on the back when the plough is in the air.

There may be some advantage in having extra weight on the front with qualitrol or complicated hydraulics but thats far too complictaed for my 1960's brain and knowledge base.

[Bensdexta]

Adding weight to the rear wheels will also improve roll stability when working across a slope. Front weights won't as the front axle is pivoted.

[AdrianNPMajor]

Many thanks, FHM.

The operator's manual talks of 'weight transference to the rear wheels when operating rear mounted equipment' and it goes on to say 'it will be appreciated that such action removes weight from the front wheels'. If the front of the tractor is sufficiently weighted, does the plough pull the rear wheels down into contact with the soil? And if so, does this mean that under good conditions with reasonable rear tyre tread depth, you don't need rear wheel weights?

[AdrianNPMajor]

Thanks, Ben. I can see how that would work. Each rear wheel is planted more firmly to the ground through the addition of weights, making it harder for the tractor to roll over when crossing a slope.

Any drawbacks to adding rear wheel weights?

[Brian]

Rear wheel weights are a waste of time! They add weight to the tractor, yes, but it cannot be used once the wheels start to slip.

We had this demonstrated so many times when the 5000 came out, the only plough for it was a TS82 and it could not pull it in heavy ground with a full set of rear wheel weights and water balast. The wheels just slipped.

Then Ransomes introduced the TS84 3 furrow reversible, we sent out demonstrators with no rear weights and full weights on the front, we even made a special box for weights so we could get more weight on the front and mounted the weights further forward. We then set about convincing farmers to buy a three furrow plough for a tractor that could not pull two!

It worked! We sold TS84 ploughs like they were going out of fashion and the weight boxes and weights as well. Never sold many sets of rear weights after that.

If you have a heavy implement on the back you need weight on the front to counteract it. If your hydraulics are working correctly, the weight on the back and the weight on the front acts on the rear wheels making them grip.

All this is with top link sensing. If you have a tractor with lower link sensing or one that pulls from the drawbar, then you need wheel weights and front weights to get grip.

[AdrianNPMajor]

The reason for asking this question is that I have been thinking about getting a set of rear wheel weights. I don't think I'll bother now.

Brian, I owe you a pint. In the meantime take two of these out of petty cash! In fact, have another!

Many thanks

Adrian

[Roadless63]

Wheel weights will give you more drawbar pull since drawbar pull is a function of the coefficient of friction available and the vertical force (ie weight) acting on the contact patch under the driven wheels. On a rear wheel drive tractor extra rear wheel ballast is termed "weight addition". Adding front weights will also assist since you gain the benefits of weight transfer, by holding the front of the tractor down as the draft (drawbar load) increases rather then picking the front of the tractor up you push the rear of the tractor down (rather a simplified expanation). The use of 3 pt linkage rather than a drawabar pushes the hitch point forward, draw lines from the top link and lower links forwards to the point where they intersect and this is a virtual hitch point (as far as I remember when I learnt about this stuff many years ago) this geometry will also aid in terms of weight transfer and explains why even setting a top link correctly/incorrectly can make a tractor seem to pull well or badly.
The need for extra ballast is usually a function of what you are trying to pull and on what ground conditions. I did have jotted down once in my lecture notes when more tyre surface area outweighed extra ballast.

[AdrianNPMajor]

Most informative Roadless. Many thanks.

Adrian

[Pascal]

Hi guys,

Of course Brian is right! But imho he is missing one small thing: wheel weights look REALLY COOL!!
I have mounted mine last Friday. Here are some pictures:









Since I didn't have the original square plates nor a drill of 20 mm, I use M20 washers and bent and cut them a bit:



I used five M16 x 55mm for the first weight and three M20 x 90mm for the two outher weights per rear wheel.

[AdrianNPMajor]

Quite agree, Pascal. They do look great. Love your ingenuity in creating the tabs.

[henk]

Looking great Pascal. Seems your idea has worked fine.

[Ian]

They would be useful if you had a loader on the front and needed extra weight. But otherwise I wouldn't bother. I can't imaging taking off a wheel with wheel weights lol.

[Kim]

Yes, they do look great but if you have a show tractor you have to haul, it's all expensive poundage that uses more fuel to cart around. At a show a few years ago, I saw a restored Case RC with weights that were almost 36 inches across. On close inspection, they had been fabricated out of wood to look like the original real thing (which are impossible to find now). It was a clever piece of (wood) work!

[Pascal]

I can't imaging taking off a wheel with wheel weights lol.

I'll let you now how the experience was...I am afraid I'll have to do the job..