Tires Why do vinyard tractors have 4 large tires?

[rox]

Whe you look at tractors for vinyards and orchards they show tractors with 4 large tires all the same size. When you look at other tractors they have small tires in the front and big tires in the back. Why is that?

 

[jgh]

20051003

My NH TN90F orchard/vineyard has the usual smaller tires in front, with 16.9 x 28 (but metric 420/70-28 designation, I think) in rear.

Not sure if I have seen what you are talking about except with ref to NH bi-directional tractors and JCB backhoes.

Picture would be welcome to asuage our curiosity about your machines /forums/images/graemlins/grin.gif

BTW, my machine was made in Italy, land of many vineyards of course.

Jim

 

[RoyJackson]

I've only seen the large rear tire, smaller front tire type tractors.
However, I'm going to make a guess about the tractors you've seen...two, actually...

First, the larger tires would put less pressure on the ground per square inch (assuming they aren't filled). This would be less damaging to the root system of the vineyard. High flotation is the word here...

Second...the tractors used in the applications you've seen may require more traction...filled and more grip area.

Both hypotheses would depend upon what was grown in those vineyards, the type of tractors and tires. Although the hypotheses seem to contradict each other, they really don't, if you think about them.

 

[RalphVa]

Saw this in The Field Guide to JD Tractors that I bought recently. It shows JD tractors all over the world (not green in Oz). The ones pictured as Goldinis had the same size front and rear. May be an Italian thing.

Ralph

 

[ZJ_HR]

Just a small remark:
420/70-28" equals to 14.9-28" by diameter, and width is 420mm, what correspond to 16.5" width of tire.

 

[ZJ_HR]

Tractor on picture is Antonio Carraro, not a Goldoni, and has steerable front tires (it is not articulated). All wheels are equal size.
These tractors have bigger weight on front axle then on rear axle (60:40%), and need bigger tires for that load and stability.
When they PULL implements, main traction came from FRONT tires. With implements on 3pt raised, it has equal load on both axles, so it give them top stability on slopes.

 

[ZJ_HR]

Rox,
If I remember correct, you have a good Goldoni tractor there on your property.
Some of their models were sold under JD name, as well as their model Star 70 use DPS (JD) engine.

 

[jgh]

20051004

ZJ, the Goodyear site says 420/70 is 16.9 inches, not 14.9. It says 14.9 is equiv to 380, another size available on my tractor, but mine are 420s.

See Goodyearag for what I base this on.

J

 

[ZJ_HR]

Just read what I wrote:
Tires 420/70 equals to 14.9 BY height (diameterof wheel), and by rim width (13"), when tread width of tire is like 16.9".
Low profile tire which corresponds to 16.9", by height (or circumference of wheel), is 480/70, and adequate width of rim is 15" for it. 480/70 tire has width like 18.4" tire, but wheel diameter like 16.9" tire.
I didn't mention rim dia, as they can be 24",28" or 30" ...
I have on my tractor 420/70-30" rears (14.9-30) on 12" wide rims, and 360/70-20" fronts (12.4-20") on 11" wide rims.
Hope we clear misunderstanding (well, English is not my native language) /forums/images/graemlins/wink.gif

 

[Jarrett]

There are alot of tractors down here with the same size tires on front and back. They're "High-crop" tractors. They have alot of ground clearance to drive over the crops.

There's also the spraying tractors too that are really cool. These are built down here in Louisiana at one of JD's subsidiaries.

 

[KentT]

IMO, they use four large tires for three reasons:

1. The most traction without compacting the soil

2. Low center of gravity for working on slopes

3. Highest possible ground clearance while retaining that low center of gravity

 

[rox]

Many thanks to all. I wondered why that was and between what everybody contributed I think I understand. We have a lot of "slopes" actually I just call 'em hills.

Low center of gravity with high ground clearence, for this terrain, really roxky and hilly yeah that makes a lot of sense.

 

[mars1952]

Whe you look at tractors for vinyards and orchards they show tractors with 4 large tires all the same size. When you look at other tractors they have small tires in the front and big tires in the back. Why is that?

Most tractors with smaller front wheels do not have true 4 wheel drive they have front wheel assist, the font tires are smaller because the front axle is weaker than the rear. The tractors that have the same size tires front and rear are true 4 wheel drive tractors and have equal power and traction front and rear. Many of the true 4 wheels drive tractors are reversible and it is necessary to for the axles to be of equal strength. I am sure there are exceptions to this.
Marshall

 

[JerryG]

Whe you look at tractors for vinyards and orchards they show tractors with 4 large tires all the same size. When you look at other tractors they have small tires in the front and big tires in the back. Why is that?

Rox,
The tractors that you are speaking about are true 4wd tractors. The are also articulated so that they bend in the middle. These tractors will turn sharper and are designed to carry weight on both ends equally. They are better on hills with a lower center of gravity.

 

[Egon]

Some of the vineyard tractors have to deal with some pretty good slopes. The design you mention Rox may be for this reason.

Vineyard on riverside picture.

 

[Bob_Skurka]

Rox,
The tractors that you are speaking about are true 4wd tractors. The are also articulated so that they bend in the middle. These tractors will turn sharper and are designed to carry weight on both ends equally. They are better on hills with a lower center of gravity.

Jerry, not all of these tractors are articulated but you are correct that many of them have that feature.

In addition to equal size tires, many vinyard tractors have TRACKS instead of tires. New Holland and Yanmar both make tracked tractors for vinyard use.