Or more generally, in a tracked vehicle.
I ran across this in the Army Times today:
Army can’t keep up with demand for parts in Iraq
I’m sure that track wear depends on the terrain, how many cars I drive over and such, but 4 months between failures seems mighty low. What’s the normal lifespan/mileage rating for these tracks ?
I don’t know specifically about tanks, but I have worked on some of the largest tracked vehicles in the world - open pit mining shovels. The tracks themselves are composed of individual steel pads which are joined to each other by a pin through a plain bearing. The track links are wear parts, but surprisingly, the limiting factor is not wear of the surface that contacts the ground, but wear of the inner surfaces which contact the drive sprocket and idler rollers, and the bearings themselves. In the course of normal operation, the machine will get all sorts of debris on the inside of the track - rocks, etc. simply get crushed between the track links and the rollers as the machine passes over them. Not surprisingly, a track which inadvertently doubles as a rock crusher has a limited service life.
In the case of the military vehicles in Iraq, it is possible that the track links have rubber treads on them instead of being solid steel, but in either case, the sand and dust that these vehicles are constantly exposed to is bound to cause some wear in the bearings which connect the track links together, leading to a loose, noisy or altogether failed connection. My money is on that as the failure mode.
-FK
I’ll try to hunt down some cites if I can, but track failure is pretty common in military vehicles. They deal with enormous wear and tear, and the basic idea behind a military vehicle is that it stands a good chance of being destroyed in action, so perfect maintenance isn’t the first thing on the designers mind. Mechanical failure was the primary cause of vehicles being lost in action in World War I, and off the top of my head I’d be surprised to find that mean time between complete track replacement on the average World War II tank was more than 10,000 miles.
Mechanical failure was also the largest single source of vehicles being lost in WW2, and probably still is today. (Especially for the mightey M1 series!)
From J.Dunnigan’s How to Make War, the figure of 1,000-3,000 kilometers is given, depending on enviromental conditions, and whether you are talking Western tanks or Russian/Chinese tanks. The latter have a much lower ‘life’ on the tracks, which is quite a problem, given their inferior (by American standards) maintenance facilities.
Normal tank tracks are linked steel plates with a rubber pad on them. That means the tank only runs on the rubber. I did my military service in a M109 howitzer. I dont know exactly how far it can go with one set of rubber pads. It depends a lot on the terrain and on the driver. If you drive on paved roads a lot and have a driver that is taking the turns rather harshly, then you have to change the rubber pads pretty soon. I would say after about 2000 km (=1300 miles). If the conditions are better you can go up to 5000 km (3000 miles)
Let me tell you, changing those things sure isnt a lot of fun. It’s actually a lot more painful than changing the whole tracks.
You actually have to hammer each single rubber pad away and hammer the new one in.
I don’t have my manual for the M109 around at the moment, but if I see it, I can have a look at the actual numbers.
So if the Warsaw Pact had invaded Western Europe sucessfully they would have to change the tracks of thousands of Tanks at more or less the same time due to wear and tear of 1500 km ? No wonder they didnt try it… logistical nightmare ! 
Brace yourself, the Soviets were working on a tank which could have done 100+MPH under battefield conditions, so they could have gotten pretty damn far into NATO territory, at lightning speed before they ever needed to worry about swapping tracks. The collapse of the Soviet Union ended the development of the tanks which was in the prototype stage at this point. I don’t know what happened to all 300 of the tanks that they built.
Tuckerfan said
Could you please provide a cite for that?
I was a grunt with 3AD in Germany in the early 90s (which was tasked with holding the Fulda Gap – one of the main avenues of approach for Soviet mech/armor) and later held down a analyst slot in a brigade S-2 with 1CD state side. We kept up with Soviet capabilities religiously and I never came across anything like that-in official briefings or Janes.
Soviet maintenance was worse than ours and I can not imagine how they would be able to maintain a system like that. Nor can I think of any modern or near future tracked, or ground vehicle for that matter, that could have a combat speed anywhere near 50 mph, let alone 100.
Hmm. Wonder if there were any shady arms dealers showing up in third-world countries with “such a deal” on brand-new tanks, “some assembly required”…
[sub]And 1920’s-style “Death Rays” to mount on them![/sub]
Don’t feel bad, MI6 didn’t know about them either.:eek:
My source for this is Car Wars: 50 Years of Greed, Treachery and Skullduggery in the Global Marketplace by Jonathan Mantle page 218.
The book goes on to say that when MI6 found out about this (they were interviewing an automotive reporter who’d just returned from the Tatra plant in Czeckloslovakia), they practically crapped in their pants.
Please excuse me if this is a bit of a hijack of this thread.
Tuckerfan, if the design was based off of a Tatra chassis then it would not be a tank. The Tatra chassis is the brain child of the Tatra corporation, a Czech company, and it would be a 8 wheel vehicle-not tracked. Any system based of of the Tatra chassis would be a AFV similar to the new Stryker system the US Army is currently starting to field.
Even as a wheeled AFV I have a hard time believing a top speed of 112mph and it also had the ability to cross a 3 meter ditch without stopping? Wow. The only way I can wrap my mind around that is to think they armored it with tin foil and it had a cork pop gun as its main gun.
Please understand my disbelief is not directed at you, but the author of the book you cited. I am not an expert but I do have a firm understanding and knowledge of current and new systems out there and none come close to the specifications given in this 1996 book. Plus, the way the quote reads it sounds like they had it in production–why hasn’t it surfaced since being outed 7 years ago?
Something else to consider, In a less than friendly area the tracks will also be subject to damage from weaponfire, driving up the maintenance curve quite a bit.
I can only offer some WAG’s to your questions. I might be able to pin something down if I spoke Czech, but I don’t, so that probably hinders things in the research aspect.
Tatra does have a number of remarkable engineering credits to their name (even if the company is largely unknown outside of Eastern Europe). It was their design that Hitler stole and gave to Porsche which became the Beetle. They also built the portible SCUD launchers which Iraq was able to effectively hide from US bombing operations during GW I.
After the collapse of Communism, Tatra had fallen on hard times and last I was able to find out, their future was uncertain (I think that one year they only produced three cars). In various searches over the years, I’ve been able to find very little on the net about the company other than mention of its cars. I do know, however that the company was reknown for it’s articulated truck chassis. (Here’s one that’s a racer and here’s a page discussing the Dakar races that Tatra competed in.)
I did just find the website for the official Tatra Museum, but my current connection’s so crappy that it’ll take me ages to crawl through the site to see if it has any information on them. I’ve also discovered that Tatra is apparently still in business.
The author of the book was quoting an article titled Tatra: The Legacy of Hans Ledwinka which appeared in the Financial Times, May 22, 1993. Can’t find a copy of it on-line, so no idea of the details.
Not as bad as you’d think. Back when, I rode in a (admittedly much lighter) tracked vehicle, the M113 APC, and trackwork was the order of the day. Although the job is heavy, dirty and unpleasant even by infantry standards, it takes no special facilities or extra personnel. The tools are on the vehicle, and the driver/co-driver team with a little strong-back assistance from the rest of the squad can replace both tracks in a couple of hours, as long as there’s a paved surface to work on.
The trick is to temporarily open the old track, connect it to the new track laid out in front, then gas up and basically back the vehicle, pulling the new track in to replace the old one. Disconnect the old track, pull the ends of the new track together (tools on the vehicle), hammer the pin through to loop off the new track and adjust the tension wheel. Presto. (Much preferable to the more common situation where you’ve somehow driven off the track and everything is crunched up, under the vehicle, in the slush. At night. While it rains. But I digress…)
Sure, tanks are about 5-6 times as heavy and you’ll probably want a truck with a light crane to handle their tracks - but basically, the job involves shifting about the tracks, not so much the vehicle.
