Why is Weight The Only Solution Being Offered To The Problem Of Traction?

[scottanddonna]

We have one member here who preaches the gospel of weight: Tractor Sizing - TRACTOR WEIGHT as ONE (1) CRITERION in TRACTOR SELECTION

My question is why aren't other alternatives being considered by the industry like this one:

I love these. Have them on my RTV because I was getting daily flats with standard tires and they do have great traction because the bottom flattens out and creates a ground contouring contact patch. Would get them for my tractor if I could afford them.

 

[LouNY]

I know that you've answered this before but will radials fit on the same rim as bias? If not, it seems like tire construction isn't the only difference.

And here I am, asking dumb questions about rim width.

Most tractor radials will fit the same rims bias ply or radial,
an 18.4-38 bias, an 18.4R38, an 460/85R38, an 480/80R38 are all recommended to be on 16" wide rims.

 

[BnRidge]

False. Coefficient if friction times normal force is one factor and dominant for flat-on-flat surfaces. When you have aggressive tread, you have to factor in the load path and essentially how mechanically locked up the tread is with the surface you are driving against. At the limit, it could be like a cog railway where the tread is interlocked with the driving surface and the force you can apply is basically limited by engine torque.

What type of conditions would mechanically lock a tread with the surface? In that case the cf would be 1. Rubber on dry asphalt is around 1. Rubber on wet smooth concrete in the cow yard is near zero it seems.

 

[Mudfarmer]

Since the 2000's the default tire on CUTs and SCUTs have been R4 tires, although R1 tires are cheaper. If you go to build-a-tractor sites like John Deere's the R4s are a pricier upgrade. I suppose the R4s are a little safer being wider and don't tear up the ground as much being flatter. But in general they are a compromise. I have R4 on my heaviest tractor a JD 3005. I have to put that tractor in the garage in the wintertime when the Pacific NW rains mud up my tree farm hillsides. The John Deere will go about 20 feet up a 20% grade dirt road before it spins out with clay mud completely clogging its treads. Kind of like going uphill on greased slicks. Weight is not the issue obviously. On the other hand, my two lighter Kubotas with R1s (I had to order the new specifically with those tires - saved a little money) have no problem at all since they are designed to throw off the mud. "Traction" takes on a whole different meaning on hilly packed clay roads.

 

[Bob Rooks]

If you look at some of the videos of the farm tractors you'll notice that quite a few of them have dual tires on the rear some have dual tires on the rear and on the front if you look out west at the big farm tractors they have triples front and rear and that is for traction in the dirt

All those tires are directly proportional to the need for Viagra. All you need is tracks.

 

[Bob Rooks]

Rubber on wet smooth concrete in the cow yard is near zero it seems.

Equal to being on ice. Zero coefficient.

 

[bdog]

I own three RTVs with tweels on them. We have had them two years. They perform better in virtually all conditions than tires and we operate in all conditions. I have had them in about seven states and conditions from swampy to rocky hills.

We primarily use them because they don’t get sidewalk cuts and go flat but they do have a larger ground contact patch and thus less ground pressure per square inch. We get stuck less.

All that being said when it comes to work and pushing a blade or dragging an implement weight is your friend. Even my dozer with steel tracks will spin out before it loses power when trying to push too hard. My first dozer weighed 20,000 lb and it was about useless for pushing brush. Trees no bigger around than my leg it would struggle with. I would have to dig around them. My new dozer weighs 40,000 lbs and takes these trees out no problem. Yes it has more HP but being able to get that HP to the ground due to weight is the big difference.

 

[kirkawilson]

 

[Cahaba Valley Farm]

My neighbor has a favorite saying - "no substitute for American cast iron". He has two New Holland compacts, with as much or more horsepower than my old IH farm tractor. But mine weighs twice what his does, and I have had to pull him out more than a couple of times. So I am on board with the weight being the most important factor. In snow and ice, chains of course are significant. We use my tractor to skid firewood logs, as he can't really accomplish much with his new machines in the woods, even with chains.

Tim

What does he have?

 

[Cahaba Valley Farm]

Power has a big impact on ability to run rotary equipment such as mowers and rototillers. But weight determines how much you can pull, unless you do not have enough power to pull even in low gear.

It's a little more complicated then that. Weight effects the size and weight of the implement that you can safely pull. It also effects how much you can lift and pull. This is where Jeff has a lot of valid points in what he preaches around here.