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.