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Komatsu D20

dirtybird

Member
Joined
Feb 25, 2005
Messages
5
Location
northwest Indiana
Occupation
option trader
I see alot of Komatsu D20 for sale for 13-20,000.


I was wondering what this machine is capable of. Can you grade out a half acre lot with some dump truck piles, and how would you compare it to a skid steer? Is it so under powered at 40 hp that you are sorry you baught it?

How would you compare it to a 50 - 60 hp tractor with a box blade?
 

Cat420

Senior Member
Joined
Oct 11, 2004
Messages
527
Location
Pine Bush Ny
Occupation
Construction, small engine and machine shop work
We rented one to do a final grade on our property. It's kind of underpowered and a little too light. I found that it pushed a sufficient amount of dirt with the throttle turned up pretty high, but this is bad for fuel consumption. I don't have much experience with dozers, but with the throttle at a normal setting I had to make several passes to spread out truck loads of dirt. It's a good weight for finish work, but not for any mass earth moving. I would rather own a 15,000lb to 18,000lb dozer and rent a small one for the jobs that need one. A large skidsteer will probably push more, but tracked machines are generally better for riding over uneven terrain and leave a nicer finished grade. Track systems for skidsteers may help with this, but that is an added expense on top of the machine cost. Hope this helps.
 

woberlin

Well-Known Member
Joined
Dec 14, 2004
Messages
111
Location
malvern, ohio
Occupation
excavating contractor/bodyshop owner
It's hard to compare a dozer to a tractor or a skid steer, tracked or wheeled. Almost any dozer, even a small one will outproduce the above machines when it comes to pushing dirt, clearing, or cutting in driveways etc. But on the flip side, that's all a dozer can do. Skidsteers and tractors have a huge variety of attachments available that can do almost any job. They also do not rip everything up, including roads, yards and driveways like a dozers single grousser steel tracks. You can also not really compare the horsepower of dozers to that of other machines. All the newer larger skid steers have higher horsepower than small dozers, but it is used differenly. My Cat D-3 only has around 70 horses, but it is around #15,000 pounds, and it will spin its tracks and never stall when against something it cannot move. What type of machine you need really just depend on the kind of jobs you'll be doing.
 

triaxle

Well-Known Member
Joined
Apr 3, 2005
Messages
61
Location
Cleveland, GA
Occupation
CEO Mid-sized Grading Company
its just a wee dozer, lad!

The series 20 Komatsu is a 7,000 pound dozer.
It is a nice small dress dozer but the controls may take some time to master.

It, like the skid steer, should not be confused with earthmoving equipment.

As someone mentioned, the torque figure tells far more about how a machine pushes than the HP rating.
 

Brianls

Member
Joined
Jun 9, 2007
Messages
12
Location
Perry GA
Comparison

I see alot of Komatsu D20 for sale for 13-20,000.


I was wondering what this machine is capable of. Can you grade out a half acre lot with some dump truck piles, and how would you compare it to a skid steer? Is it so under powered at 40 hp that you are sorry you baught it?

How would you compare it to a 50 - 60 hp tractor with a box blade?

I have a Ford 4600 (55 HP) with a heavy duty 6 ft box blade and my little D20AG does a much better job of moving dirt. so much so I built a three point hitch for the back of the D20 so it can pull the box blade. When the box was about half to 3/4 full the tractor would start to spin and not move any more unless I started to pull just what was in the box. with the D20 pulling it I can spill it ove the top. Plus the D20 can pull with the ripper teeth al the way down and the box tipped slightly forward (deepest rip). I almost ready to trade the tractor for a backhoe. But I'd have to replace the mowers for the tractor with a ZTR.

Brian
Baby dozer owner
 

machineman

Active Member
Joined
Jan 14, 2007
Messages
42
Location
Northern CA
I have a Ford 4600 (55 HP) with a heavy duty 6 ft box blade and my little D20AG does a much better job of moving dirt. so much so I built a three point hitch for the back of the D20 so it can pull the box blade. When the box was about half to 3/4 full the tractor would start to spin and not move any more unless I started to pull just what was in the box. with the D20 pulling it I can spill it ove the top. Plus the D20 can pull with the ripper teeth al the way down and the box tipped slightly forward (deepest rip). I almost ready to trade the tractor for a backhoe. But I'd have to replace the mowers for the tractor with a ZTR.

Brian
Baby dozer owner

Do you have pics of the ripper and attached box? I've never seen any on a D20. Sounds like a nice addition for some light work.

My D20p specs out just under 9000lbs. It pushed lots of dirt with traction so power is no issue. But without traction it just spins and I can barely load up the blade. I plan to weld some flat bar to the swamp tracks to resolve that issue.
 

R Leo

Well-Known Member
Joined
Apr 25, 2007
Messages
108
Location
Texas
Trade-offs

Sure they're light dozers but you also can pull them on a relatively small trailer with a 3/4 ton pickup.

For light clearing, I rarely have run mine much faster than an idle and it does a great job in low gear. Low gear is fine with me too; I'm new to this dirt pushing thing so I don't like going too fast plus, I've been working in some areas that were pretty tight.

I can see how smooth tracks could be a problem. Fortunately, my D20 has had rebar welded to the tips of the pyramid pads.



I'd sure like to see how you did that ripper too. having the ability to stick a 3-pt implement on the back wouldn't be all that bad.
 

Brianls

Member
Joined
Jun 9, 2007
Messages
12
Location
Perry GA
D20 with 3 point box blade

Do you have pics of the ripper and attached box? I've never seen any on a D20. Sounds like a nice addition for some light work.

My D20p specs out just under 9000lbs. It pushed lots of dirt with traction so power is no issue. But without traction it just spins and I can barely load up the blade. I plan to weld some flat bar to the swamp tracks to resolve that issue.

Here is a picture of the lift arms and the cylinders. I've redesigned the lift system because with this configuration the single valve lets the implement twist instead of staying level. I'll have to change the hydraulic valve to a two circuit (twin valve) so each piston has its own spool. If you can see it just below the second (electric) hydraulic pump are mounts for the upper link of the 3 point system. I'm trying a single piston upper link and stablizing bars from the implement's upper link to the center of the lower arms. That should stop the see-saw action. Next time I have the blade on the dozer I'll shoot some pictures.

Brian
 

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mtb345

Well-Known Member
Joined
Mar 23, 2007
Messages
115
Location
brockton mass.
Occupation
heavey equipment operator
rubber tracks dozer i like it. when your spreading loam in a subdivion and you haveto travel up the street to the other lot one word peeerfect:)
 

IdleUp

Well-Known Member
Joined
Jan 1, 2009
Messages
104
Location
Roanoke, VA
I see alot of Komatsu D20 for sale for 13-20,000.


I was wondering what this machine is capable of. Can you grade out a half acre lot with some dump truck piles, and how would you compare it to a skid steer? Is it so under powered at 40 hp that you are sorry you baught it?

How would you compare it to a 50 - 60 hp tractor with a box blade?

You can grade out 50-100 acres if you have the time - the D21 will outperform a skid steer 50 to 1 - you can't even compare the two machines. In addition, the 6 way blade on the D21 puts it in a new category when compared to a box blade. Forget the tractor or skid steer.

Get the D21 do your job and when your done - put it back on the market and chances are you won't lose a dime.

Thanks
 

PonyExpress94

Active Member
Joined
Jan 13, 2009
Messages
42
Location
Maryland
I have a D21E-6 and love the machine. I purchased it for the sole purpose of work around my parents property because our New Holland Tractor with loader and backhoe was inefficient for the work as was a 3 pt. hitch woods back blade. I had previously looked at renting a John Deere 450D from Sunbelt rentals but the dozer was too big for some of the areas I needed to work and renting it was was cost prohibitive for the length of time I would have needed it.

Long story short...I found a 1991 D21E-6 with the 3-speed powershift tranny for $13,000 and it took me all of a day to decide to buy it and I haven't looked back. My owners manual says the machine weighs 8818 pounds and it has a drawbar pull of approximately 9000 pounds. This thing is easy to use and can move some dirt!!! My only issue right now is that I need new grouser bars on my tracks.

One suggestion as far as moving larger quantities of dirt is to have the trucks tailgate the dirt if possible instead of just dumping in piles. It saves you some work of having to move the dirt as far and you spend less time knocking the piles down.

On Edit: I can run the dozer for 8-10 hours before I need to add fuel. My fuel tank is 15 gallons and I run the engine at full throttle so that I don't lug the engine.
 
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JimInOz

Senior Member
Joined
Apr 15, 2008
Messages
511
Location
Victoria, Australia
D20

The D20 has a gearbox,so you get lots of power to the tracks.You'll make a great little dozer out of it with Standard dozer plates & Ripper/Scarifier on the rear.
The rubber & swamp tracks are OK for their applications,but standard track plates will give real dozer performance.The difference between swamp plates & standard shoes is vast,when doing dozer work like excavating.There are many track suppliers out there.

You'll need a little time to level a truckload of dirt,but the machine will push dirt,clear small scrub & excavate a shed site (if ripper fitted).They also pull a decent sized fallen tree....all on low fuel usage.

Jim
 

Brianls

Member
Joined
Jun 9, 2007
Messages
12
Location
Perry GA
The rubber tracks I put on my D20 have a tractor style tread and grip on most dry surfaces better than the original tracks did. I would spin tracks and dig right in at half throttle with the old tracks. Becaus they only linked to the drive sprocket on every other tooth I was always having problems. The new tracks will stall the engine at 3/4 throttle of you get up against something that doesn't want to move.
 

pel123

New Member
Joined
Apr 11, 2010
Messages
3
Location
CT
Komatsu D20P-5 Steering clutches

Does anyone know when replacing the steering clutches on a Komatsu D20P-5 do you have to remove the final drive or can you pull the brake drum/clutch housing assembly out after unbolting both sides? I see it has bolts on the sprocket side and the transmission side, but are there splines in the middle, or will the whole assembly slide up? I have to replace the clutches on both sides? Any input or help would be great. Thanks! Pete
 

darinray

Charter Member
Joined
Nov 15, 2003
Messages
435
Location
Delevan, NY
Occupation
Owner-Equipment & Parts Sales
I can fax you or email you the procedure. The clutches and brake band come out as a assembly from the top of the machien by removing seat and linkages and unbolting the top housing. NO taking tanks off or removing final drives. Contact me anytime.

Darin

Does anyone know when replacing the steering clutches on a Komatsu D20P-5 do you have to remove the final drive or can you pull the brake drum/clutch housing assembly out after unbolting both sides? I see it has bolts on the sprocket side and the transmission side, but are there splines in the middle, or will the whole assembly slide up? I have to replace the clutches on both sides? Any input or help would be great. Thanks! Pete
 

pel123

New Member
Joined
Apr 11, 2010
Messages
3
Location
CT
That would be great if you can e-mail me the procedure. My e-mail is peteloomis@comcast.net I haven't taken this apart before and didnt want to take apart more than I had to. Thanks for the help! Pete
 
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