Why a center pivot on the front axle?

[Henro]

In a different thread, I came to realize I have no clue why tractors generally have a center pivot on the front axle.

I mean as compared to say some other serious off road designed vehicle (like a Unimog) that has four point suspension like a jeep and other vehicles do.

Why is this?

Simple question, simple answer? Again, I have no clue...

 

[GreensvilleJay]

It's cheap,simple and reliable..... ONE bushing to grease,One pin......

 

[foobert]

There's no need for the complexity of suspension. But a rigid 4-wheel system only rests weight onto 3 points for any normal terrain (ala: not flat), so, the front axle pivot keeps the weight distributed to all 4 tires.

Doesn't have to be the front axle. Look at any purpose built wheel loader -- front axle is stationary since that's the primary fulcrum under load and rear-axle has the pivot.

 

[Magicman]

Simple answer, it keeps all 4 of my feet on the ground..

 

[OrangeKrush]

It's cheap,simple and reliable..... ONE bushing to grease,One pin......

Bingo!

 

[tractorX]

like this... independent suspension with 4 tracks! watching those quadtrac and rowtracs working the fields is very impressive... so why not a kubota quadtrac CUT with independent suspension?
my bro n law has this same set up on his
polaris for snow removal round the house... dirty road and hill he's gotta deuce-and-a-half with plow for that iowa snow.

 

[mcfarmall]

People are crying about the price of tractors and then ask for tracks and independent suspension on all four. I give up.

 

[Magicman]

I don't just drive my tractors around and there is no way that struts, etc. be rugged enough for any tractor that I use. The tires are all of the suspension that I want or need.

 

[D2Cat]

Now wait a minute. Quite a few folks have been complaining about their seat not having adequate movement lately. That is a bit of suspension also!

 

[Henro]

There's no need for the complexity of suspension. But a rigid 4-wheel system only rests weight onto 3 points for any normal terrain (ala: not flat), so, the front axle pivot keeps the weight distributed to all 4 tires.

Doesn't have to be the front axle. Look at any purpose built wheel loader -- front axle is stationary since that's the primary fulcrum under load and rear-axle has the pivot.

Looks like GreensvilleJay and Foobert listed the most important reasons.

Simplicity and best traction by keeping all four wheels on the ground.

 

[Crash277]

Take a bx23s weighs 3000lbs. Go to fill the bucket and lift 600 lbs. the suspension would have to be able to handle that plus the breakout force. A

 

[Henro]

Take a bx23s weighs 3000lbs. Go to fill the bucket and lift 600 lbs. the suspension would have to be able to handle that plus the breakout force. A

Another good point. Otherwise the tractor might feel like a marshmallow with a loader on the front!

But I think keeping all four wheels on the ground nearly all the time is probably the key reason...along with simplicity.

 

[NHSleddog]

To keep all 4 wheels on the ground.

And the wider you make it, the more you will have all 4 wheels on the ground.

 

[Henro]

To keep all 4 wheels on the ground.

And the wider you make the more you will have all 4 wheels on the ground.

ROFLMAO (Sorry everyone, inside joke )

 

[OrangeKrush]

ROFLMAO (Sorry everyone, inside joke )

and we’re outsiders now??

 

[NHSleddog]

and we’re outsiders now??

No, it is from another thread. Henro thinks having a wider front axle makes no difference to stability, the poor guy can't get past the pivot.

I believe a wider axle provides more stability. I drew cartoon pictures for it and everything. Common sense proves it out, experience proves it out and most importantly math proves it out. I'm not sure why he finds it so funny though.

 

[Magicman]

Just offer to buy him some "training wheels" for dat narrow tractor.

No need to go wider to prove your point. Just go more narrow and make the comparison with a tricycle style tractor and your point is proven. Ever wonder why 3 wheelers were discontinued and replaced with 4 wheelers??

 

[NCL4701]

Funny about the front axle. I’ve always sort of wondered if we slid the rears all the way out on the row crop H would it be super stable at about 10’ wide in the rear despite the two wheels a couple inches apart on the front and the center of gravity being WAY high. If I ever get really bored and have a death wish maybe I’ll slide them out and try brush hogging the sewer line.

 

[Henro]

No, it is from another thread. Henro thinks having a wider front axle makes no difference to stability, the poor guy can't get past the pivot.

I believe a wider axle provides more stability. I drew cartoon pictures for it and everything. Common sense proves it out, experience proves it out and most importantly math proves it out. I'm not sure why he finds it so funny though.

I find it funny because you can't leave a sleeping dog lie, AND you constantly misrepresent my statements...as you did in the post I am replying to.

Somehow you cannot seem to see realize that the front axle has a different effect on stability, depending on whether it is free to move or locked against a travel limit stop...It is that simple really.

Common sense dictates you cannot ignore segments of a mechanical system that are variable during operation. A pivoting front axle is one such segment. It is not a fixed piece like a rigidly bolted in place axle would be. If it were fixed, it would function like the rear axle as far as effect on stability goes. Wider would always be better in that case. But it is not fixed, so it cannot be treated exactly the same.

For understanding, both modes of operation must be considered. Your analysis ignores the one that is most common during normal operation.

 

[GreensvilleJay]

re: Ever wonder why 3 wheelers were discontinued and replaced with 4 wheelers??

answer... to make MORE money ! plain and simple..aside from more parts = bigger 'sticker' price.... it allows MORE idiots to buy them and TRY to drive them.....

same as why the CJ-7 came out. AMC needed 10 more inches to get the automatic tranny in, so that 'nonstickshifters'( prinicpally women and 'kids' ) would buy and drive a JEEP