How far can you tow a tank on it's road wheels?

[On the way]

Assuming it's a paved road. Tank with no tracks but all road wheels intact, is being towed by say another tank or tractor. Obviously terrain will also affect the tow, but let's say for now, it's paved road. Can it be towed indefinitely with no damage to the suspension? I am going to say the drive sprocket and idler wheels are not in contact with the paved surface.

[Markus Becker]

*sncr*

 

[Stuart Galbraith]

51 minutes ago, On the way said:

Assuming it's a paved road. Tank with no tracks but all road wheels intact, is being towed by say another tank or tractor. Obviously terrain will also affect the tow, but let's say for now, it's paved road. Can it be towed indefinitely with no damage to the suspension? I am going to say the drive sprocket and idler wheels are not in contact with the paved surface.

Dont see why not. I remember once seeing a Gypsy caravan that was toting what  appeared to be Cromwell or Comet wheels, and had presumably been running on them for several decades. Which I had a photograph of that.

The rubber will probably get beat up if you are packing a lot of weight across a rough surface, but I would imagine the ground pressure on each wheel and axle will be slightly less if anything, because you wont have the upper run of track weighing on it.

[Ssnake]

49 minutes ago, On the way said:

Assuming it's a paved road. Tank with no tracks but all road wheels intact, is being towed by say another tank or tractor. Obviously terrain will also affect the tow, but let's say for now, it's paved road. Can it be towed indefinitely with no damage to the suspension? I am going to say the drive sprocket and idler wheels are not in contact with the paved surface.

I don't think I was ever instructed on range limitations in driving school, or other tank-related courses. There are, at least, no inherent limitations for any tank suspension that I know of. Once that the drive sprocket is disconnected - either by track removal or by decoupling it from the transmission gearbox - the parts that still have to move are mechanically passive and do what they always do. Wheel arms or springs go up and down, reaodwheels rotate, whether they are on a track surface or a road.

You would still want to check for leakage of the roadwheel lubrication every X kilometers per tank's manual to make sure that nothing overheats and catches fire.

[Ssnake]

Yes, the rubber bandages would suffer eventually. But on a reasonably clean paved road they would certainly last a few hundred kilometers if not more than a thousand. (Now we're starting to drift into the absurd, obviously; for all practical matters I see no limit.)

[sunday]

No brakes, however.

[Rickard N]

3 minutes ago, sunday said:

No brakes, however.

You generally don't have brakes when towing a tank.

[Tim the Tank Nut]

you'd never damage the actual suspension, just take the rubber off the roadwheels.  I think that would happen pretty quickly.  Here's why:  When the tracks are on the road wheels they are always "going straight".  The tracks turn but the roadwheels aren't subject to significant lateral stress because the track absorbs it.  If you hooked up a tank to a tow bar (you could not pull it with a chain, it wouldn't turn or stop) when the tank turned the roadwheels would be subject to a serious lateral load.  The rubber would come off pretty quickly.

There is a picture posted in one of the forums of a tank with the track shortened.  It shows real wear to the exposed road wheels.

[old_goat]

12 minutes ago, Tim the Tank Nut said:

If you hooked up a tank to a tow bar (you could not pull it with a chain, it wouldn't turn or stop) when the tank turned the roadwheels would be subject to a serious lateral load.  The rubber would come off pretty quickly.

Skid steer loaders turn the same way, and their tires do not come off. Of course running them on asphalt or concrete increases wear significantly, but it is not that bad.

[Tim the Tank Nut]

but they are made for it.  Most of my experience is with older stuff and maybe modern tanks are made differently but I'm pretty confident in my assessment.

Using the skid steer as an example it's typically 4 tires (one per hub) and they are inflated rather than solid.  The skid steer suspension is short (front to rear). On a tank there are many more wheels on the ground and in a turn they're all fighting each other.  There's no lateral give designed into the suspension because it would throw the track if it was there.

[old_goat]

13 minutes ago, Tim the Tank Nut said:

Using the skid steer as an example it's typically 4 tires (one per hub) and they are inflated rather than solid.  The skid steer suspension is short (front to rear). On a tank there are many more wheels on the ground and in a turn they're all fighting each other.  There's no lateral give designed into the suspension because it would throw the track if it was there.

There are solid tires for skid loaders too btw. As for the suspension, there is none. Everything is rigid. As you described, the wheels are fighting each other. I dont know if you have ever operated one, but it is very noticeable when turning especially with a full bucket. Sometimes it is accompanied with a violent jerking.

[rmgill]

51 minutes ago, Tim the Tank Nut said:

 If you hooked up a tank to a tow bar (you could not pull it with a chain, it wouldn't turn or stop) when the tank turned the roadwheels would be subject to a serious lateral load.  The rubber would come off pretty quickly.

Well it would when it smashed into the back of the towing vehicle. 

🙃

/Mr Picky


But yes, every time you did any slightly dramatic turns, you'd be side scrubbing the rubber tyres on the road wheels. Eventually, you'd shed them. 

Edited January 15 by rmgill

[rmgill]

2 minutes ago, old_goat said:

There are solid tires for skid loaders too btw. As for the suspension, there is none. Everything is rigid. As you described, the wheels are fighting each other. I dont know if you have ever operated one, but it is very noticeable when turning especially with a full bucket. Sometimes it is accompanied with a violent jerking.

Skid steers are shorter length vehicles as a rule. And there are 4. Not 8 or 10 or 12. And they're typically on soil/gravel and only sometimes on pavement. That allows a greater degree of slippage for the skidding. 

And they run at very low speeds. Higher speed towing for protracted distances will heat the rubber compound up, making it softer which will lead to increased scrubbing of the front and rear road wheels and thus the tyres will be damaged. 

The Brits did experiments with skid steer AFVs in the 50s. The vehicles that led to the Saracen/Saladin had a skid steer prototype that was found to have excessive tire wear so that avenue was not pursued. 

[old_goat]

12 minutes ago, rmgill said:

The Brits did experiments with skid steer AFVs in the 50s. The vehicles that led to the Saracen/Saladin had a skid steer prototype that was found to have excessive tire wear so that avenue was not pursued. 

Now that you mention it... There is the AMX-10RC from the french. That is definitely a skid steer. With full armor kit, a rather heavy one. 

[rmgill]

Yes. But radial XL tires have FAR more give and flex and heat capacity than solid rubber tires around a non flexible metal roadwheel. 

And note that the AMX-10RC is an exception, not a rule. 

Speed and tire composition matter a LOT to heat build up. I've watched over heating roadwheels on a halftrack shed the rubber tyres. 

[Tim the Tank Nut]

replying to old-goat:

yes, I've done all this stuff including the skid loader. 

Replying to rmgill:

I've seen the halftracks pitch rubber too,  If they'd properly maintain the bearings the wheels wouldn't likely overheat enough to shed even the oldest rubber.

We have tow barred many tanks including rubber on the ground without tracks on.  It's okay on slick garage floors but out on pavement it just shreds the rubber in any turn.  Naturally the rubber we were working with is old.

Just thinking about this stuff makes me tired.  I'm surprised to admit that I don't miss it at all.

[rmgill]

34 minutes ago, Tim the Tank Nut said:

 

Replying to rmgill:

I've seen the halftracks pitch rubber too,  If they'd properly maintain the bearings the wheels wouldn't likely overheat enough to shed even the oldest rubber.

Sometimes you find bearing issues the hard way. We had guys pouring water on a road wheel to keep it coolish while riding from Ike’s Farm to the town battle. 

34 minutes ago, Tim the Tank Nut said:

We have tow barred many tanks including rubber on the ground without tracks on.  It's okay on slick garage floors but out on pavement it just shreds the rubber in any turn.  Naturally the rubber we were working with is old.

Aye. 

34 minutes ago, Tim the Tank Nut said:

Just thinking about this stuff makes me tired.  I'm surprised to admit that I don't miss it at all.

That makes me sad. 😔 

 

Do you know Dave Gordy over in Iowa? 

Edited January 15 by rmgill

[Tim the Tank Nut]

I know of him but I can't recall working with him.  

 

Don't be sad, nothing lasts forever and at the tempo we were operating at a twenty year run was an astonishing accomplishment.  I'm glad/relieved that I stopped at the top rather than screw something up and get somebody hurt.  It was a unique time.  A lot of the world has changed.  I'm proud of the accomplishments but it is a young man's game.

 

As far as tire and wheel wear goes there's not much you can do when halftrack track snaps.  Once that wire is broken it's done.

[Tim Sielbeck]

6 hours ago, Tim the Tank Nut said:

If you hooked up a tank to a tow bar (you could not pull it with a chain, it wouldn't turn or stop)...

The whole point of crossing the tow cables when hooking them up is so that the tank being towed is easier to turn.  As for stopping, unless it is a significantly steep incline, the towed tanks weight will bring it to a stop quite nicely.

[On the way]

18 hours ago, Markus Becker said:

*sncr*

 

The road wheels have their own drive axle? !!! WHy?

[Tim Sielbeck]

It was a weird time for tank designs.

[rmgill]

1 hour ago, On the way said:

The road wheels have their own drive axle? !!! WHy?

Faster speeds on paved roads. These were Wheel-Cum Tracked types. It was an attempt to basically get the wheeled speed of an armored car with the heavier protection of a tank (not that that was huge). 

Compare them to the other tanks of the era which were FAR slower. 

[Mike1158]

7 hours ago, On the way said:

The road wheels have their own drive axle? !!! WHy?

To remove the need for tank transporters between different deployment areas.

[Stuart Galbraith]

TBF, I think most nations experimented with tanks that could self deploy. Britain went so far as to build a prototype of a machine that could lower wheels for movement on road, then drop back on the tracks when the going got bad. By the late 30's, everyone had figured out that it was just one more complication you didnt need in a mass produced tank, which was quite expensive enough.

To be fair, taking the tracks off and having a driving axle wasnt the worst solution to the concept, but with the state of the Soviet unions roads, you really have to ask why they bothered.

[bojan]

Another reason was that period tank tracks were very unreliable and prone to breaking, slipping etc. 

  

8 hours ago, On the way said:

The road wheels have their own drive axle? !!! WHy?

No driven axles as such, IIRC two rear axles were driven by the chain going from a sprocket. When in normal mode with tracks that chain drive was removed.