Are they "greased" and what do they use?
How do they keep them from getting clogged with crap?

tank tracks generate a large amount of heat when in use.  This is especially true around the bogie wheels, in order to combat this, inside each bogie wheel is a sealed compartment full of a heavy liquid oil.  This oil helps to cool the bogie wheel.  However you must keep an eye on the oil level through the plastic viewing window on the outside of the bogie wheel, and you must make sure the plastic viewing window isn't cracked.  This will allow the oil to flow out, and your bogie wheel might overheat.

The tracks themselves arnt greased,but the road wheels etc have to be greased,also IIRC we would pump grease into the tensioner when doing pmcs(M113).

Quoted: How do they keep them from getting clogged with crap?

The gazillion-dollar-question.

Such clogging is a primary cause of throwing track. i.e. so much dirt gets between the roadwheels and the tracks during a turn that the wheel pops right off. This could be an annoying thing (5-minutes of maneuvering to get it back on), or a really annoying thing (45min/hour of breaking track and re-connecting it)

You will note that early model M-1s had a track skirt that covered the drive wheel. In the field, this #7 skirt was often removed because it was great at clogging the tracks. Most drive wheels have mud relief holes in them, the mud is sqeezed between the track and the hub of the wheel, and comes out the side. The #7 skirt prevented the mud from escaping, causing problems. As a result, a new-shaped #7 skirt was created with a notch in it, allowing egress of mud.

NTM

What I can tell you about tracks is this:

1-  The prospect of throwing on off doing a hard turn in sand is enough to make even the most composed E-7 in the world scream at his driver like a little girl in a panic.

2-  When you have to change track due to the shoe wearing out, you want to make an excuse to be out of the motor pool that day.

3-  If you are at NTC, you WILL break track at least two times during turn in.

4-  They are a bitch to clean at the wash rack, especially the inside road wheels.

Having driven both the  Bradley Fighting Vehicle and the M-113A3 as a young troopie, I can honestly say that the experience can be summed up thus: Hohenfels + Spring in  the F.R.G. + shitty PVS5 nods = thrown track and pissed off and muddy, wet PFC.

Oh and by the way, mud and debris will often just be thrown off by the motion of the tracks as they round the drive sprocket and road wheel, a-la rooster tail.

I was wondering how they cool the tracks but the oil filled bogie wheel makes sense.
I was watching a show on National Geographic and it was kinda cool to see them skid a Abrahms on the test track.

I thought this was going to be about "recognizing" tanks from their tracks - and I was going to have to admit that I was always bad at that

However - the Centurion tracks were always easy to identify

Quoted: Quoted: How do they keep them from getting clogged with crap? The gazillion-dollar-question. Such clogging is a primary cause of throwing track. i.e. so much dirt gets between the roadwheels and the tracks during a turn that the wheel pops right off. This could be an annoying thing (5-minutes of maneuvering to get it back on), or a really annoying thing (45min/hour of breaking track and re-connecting it) You will note that early model M-1s had a track skirt that covered the drive wheel. In the field, this #7 skirt was often removed because it was great at clogging the tracks. Most drive wheels have mud relief holes in them, the mud is sqeezed between the track and the hub of the wheel, and comes out the side. The #7 skirt prevented the mud from escaping, causing problems. As a result, a new-shaped #7 skirt was created with a notch in it, allowing egress of mud. NTM

+1000 on that.  That chunk of aluminum would bulge out about 5 inches from the mud packed underneath.  Quite the chore to get the pins out under that much pressure.  

ETA:  A big cause of throwing tracks was improper track tension.  The M1 was a vast improvement over the M60.  M1 tension was adjusted with a grease gun and relief valve,  where with a M60  you used a string with end connectors tied to each end.

Oh  the fond memories that come flooding back! There is nothing like busting track in 6-8 inches of thick clay mud at Ft. Knox or maybe changing two or three torsion bars on a single M60 at the same time. Damn was I glad to get transitioned over to the M1! I cant count the number of torsion bars, frog legs and final drives that I helped replace on a M60 but cant rember a single one for the M1.


BKVic

Quoted: What I can tell you about tracks is this: 1-  The prospect of throwing on off doing a hard turn in sand is enough to make even the most composed E-7 in the world scream at his driver like a little girl in a panic. 2-  When you have to change track due to the shoe wearing out, you want to make an excuse to be out of the motor pool that day. 3-  If you are at NTC, you WILL break track at least two times during turn in. 4-  They are a bitch to clean at the wash rack, especially the inside road wheels.

Listen to this man!  

The British have a track tensioning system on the Challenger 2 that American tankers would die for.

American system:
Start process:
Get wire brush and chisel. Clean off caked-on mud around the greasepoint.
Get grease gun. Crank a few times, see if there's grease in it.
Apply grease gun to grease point.
Start pumping.
After a dozen pumps, remove grease gun.
Pump again to make sure that there is indeed still grease coming out.
Replace grease gun.
Pump for three minutes with little visible effect
Pull out grease gun, pump to make sure there is grease coming out. Curse when there isn't.
Open grease gun. Note that there is no grease.
Remove empty grease tube. Wipe hand on colleague's back.
Insert new grease tube.
Close grease gun.
Grab grease-gun by the T-handle, and start swinging it wildly around your head for a minute.
Pump grease gun to ensure grease comes out.
Reapply grease gun.
Pump for the next two minutes.
After little visible effect, remove grease gun.
Pump to see if grease is coming out. Nothing will come out.
Swing the pump around the head a bit more.
Pump. Nothing will come out. Declare grease gun defective. Obtain grease gun from another tank.
Repeat all stages up unto this point.
After a third grease-gun is obtained, track will finally be tensioned.
If an older model idler arm, get large spanner and screw the retaining bolt in place.
End Process.

British method:
Start process:
Shout at driver to tension track.
Driver pushes putton.
End process.

I swear, whoever designs American tanks doesn't give a hoot about livability factors that aren't in the Army requirements.

NTM

Tanks are cool.

i have question about track movement. i have been told that while a tank is sitting still you can draw line in dirt from any one of the tracks in the dirt and when the tank moves that line and paticular track will stay in line with each other because tracks dont actually move they are just a surface for the tank to roll on. i hope that is easily understood question.  is there any truth to this statement.

Quoted: i have question about track movement. i have been told that while a tank is sitting still you can draw line in dirt from any one of the tracks in the dirt and when the tank moves that line and paticular track will stay in line with each other because tracks dont actually move they are just a surface for the tank to roll on. i hope that is easily understood question.  is there any truth to this statement.

correct, its not like they perform burnouts as they drive

So how would you tension the track on a Shiva?  Or how about Tiger II?  Those bastards are big and I wouldn't care to throw a track when the Posleen are swarming!!

Quoted: Quoted: Quoted: How do they keep them from getting clogged with crap? The gazillion-dollar-question. Such clogging is a primary cause of throwing track. i.e. so much dirt gets between the roadwheels and the tracks during a turn that the wheel pops right off. This could be an annoying thing (5-minutes of maneuvering to get it back on), or a really annoying thing (45min/hour of breaking track and re-connecting it) You will note that early model M-1s had a track skirt that covered the drive wheel. In the field, this #7 skirt was often removed because it was great at clogging the tracks. Most drive wheels have mud relief holes in them, the mud is sqeezed between the track and the hub of the wheel, and comes out the side. The #7 skirt prevented the mud from escaping, causing problems. As a result, a new-shaped #7 skirt was created with a notch in it, allowing egress of mud. NTM +1000 on that.  That chunk of aluminum would bulge out about 5 inches from the mud packed underneath.  Quite the chore to get the pins out under that much pressure.   ETA:  A big cause of throwing tracks was improper track tension.  The M1 was a vast improvement over the M60.  M1 tension was adjusted with a grease gun and relief valve,  where with a M60  you used a string with end connectors tied to each end.

You forgot about the huge ass wrench to actually tighten the turnbuckle thensioner thingy on the M60s.

So...  As no one has asked this yet Ill be the one.

How much air pressure do you inflate the road wheels to?



-K
 

For a while I was driving an M-577 comand post.  Based on the M-113A2 but with some mods- higher roof, more radios, a generator, etc.  We never threw a track, but were extremely anal about track maintainance.  The biggest problem we had was clay mud bulding up over the top of the track between the hull and the track.  Was a huge PITA to clean out.  Must have been much worse for the larger vehicles.  It would get so bad that it would really slow the track down due to the drag it would create.

Once at NTC we had a defective grease fitting.  Ordered a new one for it and it was defective too.  So we drove it with VERY low track tension.  I was the driver, so I took it as easy as I could, but was expecting to throw track and maybe flip it over at any time.  Because it was so high it was a bit top heavy and rolling was more of a concern for us than in the regular 113's.  Despite some long road marches we never had a problem with it.  Eventually we got it fixed and were good to go.


-K

Quoted: Great traction, very low surface pressure

The M1A1 put out a surface pressure of around 12-14 psi IIRC from my days as a Abrams crewman