why aluminum?

[oldboyscout]

I'm still trying to decide between a Kubota B2920 and L2800. Irealized that besides the "component bolted to frame" of the B's and the traditional solid casting of the L,
the B's have aluminum rear ends.
What is the purpose of that?
Usually one would use aluminum for lightness, but in a tractor that's counterproductive

 

[dfkrug]

That's a good question. At least with the smaller tractors, like
Kubota's Bs, there are competitor machines (e.g. JD 2xxx) that use
cast aluminum in structural areas.

OTOH, Deere is the only company I know that uses cast Al in major
structural areas (rear axle housing and gearbox) for tractors in
Kubota's L class (2500-3500#).

I went into this at length during my repair of broken Al castings in my
JD4300 project, and I have asked JD directly about this. No answers.

 

[teg]

...Usually one would use aluminum for lightness, but in a tractor that's counterproductive...

Unless you want to mow the yard weekly with it...

What are your main use going to be... You can always add more weight.

 

[RoyJackson]

Main thing is low cost of manufacture.
My 4400 has those aluminum castings...and yes, I'd prefer cast iron or cast steel. But there's a heck of a lot of these Deere machines around that have never had a problem.

 

[oldboyscout]

I would have expected the aluminum to be more expensive!

 

[pat32rf]

While the cost of raw aluminium may be more, the cost of casting, machining and TRANSPORTING the aluminium castings, both before and after assembly is probably less. Plus, as has been mentioned, you can always add weight....
I just wish they had thought of the corrosion on those steel brake levers going thru the aluminium casting and used bronze inserts somehow....

 

[oldboyscout]

Oh Geez....now I want the L2800 instead.....

 

[dfkrug]

Main thing is low cost of manufacture.

I am not so sure of that. Modern cast steels may require higher
temps to cast, but are very machinable. Material cost is much lower
for steel, of course.

I can't see the transport costs being a significant difference since
container and trucking costs are volume-based, except for extremely
dense cargo.

What stands out is that other makers of this class of tractor do NOT
use Al.

 

[oldboyscout]

Are there known instances of unusual wear or damage to an Aluminum tractor due to heavy use (not abuse)?

 

[dfkrug]

Are there known instances of unusual wear or damage to an Aluminum tractor due to heavy use (not abuse)?

It is hard to say. What constitutes abuse? Some would say rental
service is abuse, by definition. Sometimes, perhaps.

Anyway, both of my JD4300s have had broken axle housings when they
were in rental service. One I fixed, and the other got a new housing
installed by Deere.

 

[magicheater]

Oh Geez....now I want the L2800 instead.....

Sounds like you have made your choice!

 

[oldboyscout]

well..sort of..
what I really want is a b2920 made of iron...

 

[Don87]

I'm still trying to decide between a Kubota B2920 and L2800. Irealized that besides the "component bolted to frame" of the B's and the traditional solid casting of the L,
the B's have aluminum rear ends.
What is the purpose of that?
Usually one would use aluminum for lightness, but in a tractor that's counterproductive

IMHO, tractors and aluminum don't go good together.

I personally won't buy a 'tractor' with an 'aluminum' rear or front end

Case in point: http://www.tractorbynet.com/forums/...g/183225-john-deere-2305-compact-tractor.html

 

[varmint]

This is a very interesting issue! I hope that someone with inside knowledge will shed light on the reasons aluminum is used over iron. I am happy that my old B8200 is almost all steel and iron- just seems like the best material for something that is intended to last a long time and get hard use occasionaly under less than ideal conditions. The weight is almost always desirable- my tractor isn't that heavy to begin with.

 

[dfkrug]

well..sort of..
what I really want is a b2920 made of iron...

The closest thing to what you want may be a Kioti CK20/Bobcat
CT120 (22hp). These are super-robust 2000# tractors that are all-steel.
A few more HP, and they would be better in many ways, IMO. In terms
of comparables, the CK20 weighs about the same with about the same
hp as a Kubota B21, a commercial unit that costs 2x.

Anyone know of other current model 2000# CUTs that are all-steel?

(BTW, the B21/B26 uses steel axle housings, but Al gearbox. BUT, it
also has an all-encompassing steel "mainframe".)