Is there a logical explanation for why vehicles can sprint?

[Inspector2311]

I get why a 'Mech could move faster if it foregoes attacking.  Not only is the pilot focusing completely on movement in order to get that extra speed out, but the 'Mech is also likely to be literally sprinting.  The arms and torso are swinging around with abandon in order to get that extra energy out, just as a sprinting humanoid would do, and that would preclude the normal operation of the targeting systems.

So far, so good.

But how can a tank sacrifice firing to go faster?  It has a separate driver and gunner, so it's not like the gunner is unable to fire because he's concentrating on making the tank go faster.  And while a tank might bounce more because it's going faster, that's not really the same thing as above.  The stabilizers should compensate for extra speed, just as they do in a slightly faster tank.  Or just as they do when that tank moves faster due to gravity/roads/etc.

So, my question: is there a logical explanation for why vehicles can sprint, or is it just a rules/balance thing?  I was going to house rule this in my campaign because it didn't make sense to me, but I figured I might as well ask if anyone knew of / could think of a logic behind this.

(Assuming, of course, that I've read the rules correctly and vehicles actually can sprint.)

[Fortyone]

Because the stabilizer in a Von Luckner isn't the same as the stabilizer in a Regulator and sprinting is moving at a speed that exceeds the mechanical limits of the stabilizers on a given vehicle.

That's about as logical an explanation as I can give.

[nckestrel]

Standard ground movement assumes the vehicle is taking some care to 1) attack and 2) evade.  You are watching the enemy maneuver and reacting.
Sprinting ignores those concerns.  That’s why you can’t attack, and why you don’t get a better TMM despite moving further. 

[PuppyLikesLaserPointers]

Well, not only Battletech does the same thing. For example, old rules of Warhammer 40,000 also says a tank cannot fire at all if it moves too fast. I am agreed on both of them above; sprint speed is too fast to keep your aim by the stabilizer(or, the stabilizer worth for their initial speed) so it seems that you can't make an attack at all, or even if you are try to do so you are not able to aim anything.

Yes why a slower tank cannot shoot at all even if it have slightly more speed than its flanking speed is a valid question, but it seems that Fortyone have the answer for this, I think. Also as nckestrel said, 'because the driver only focus on move the vehicle you cannot have a chance to aim the enemy' seems also a good reason to explain this.

Perhaps, allow to shoot with more penalty seems not so bad either, for anyway as OP said most combat vehicles have both a driver and a gunner while most mechs only have a pilot to take both roles. But anyway I think that the end result is not very diffrent.

[Inspector2311]

sprinting is moving at a speed that exceeds the mechanical limits of the stabilizers on a given vehicle.

Yes, I had thought of that... but it presumes that every vehicle actually has a speed which exceeds the mechanical limits of its own stabilizers.  I was under the impression that modern MBTs could go flat out over most terrain and not exceed their stabilizers.  I could be wrong about that, but even so, one would think that 30th+ century vehicles could.  (Yes, I know, there's a lot of WWII type stuff in Battletech rules, LosTech, etc... that's a whole other discussion...)

Standard ground movement assumes the vehicle is taking some care to 1) attack and 2) evade.  You are watching the enemy maneuver and reacting.
Sprinting ignores those concerns.  That’s why you can’t attack, and why you don’t get a better TMM despite moving further.

Hmm... I might be able to work with that.  Thanks.

[MyndkryM]

Or...

[Inspector2311]

Or...

Very much that.  I also would have accepted "VTEC just kicked in, yo."

[Fortyone]

Yes, I had thought of that... but it presumes that every vehicle actually has a speed which exceeds the mechanical limits of its own stabilizers.  I was under the impression that modern MBTs could go flat out over most terrain and not exceed their stabilizers.  I could be wrong about that, but even so, one would think that 30th+ century vehicles could.  (Yes, I know, there's a lot of WWII type stuff in Battletech rules, LosTech, etc... that's a whole other discussion...)

Yes and no. We currently have the technology for modern tanks to track pretty well at speed, but that's partly because they are speed limited by their design. An Abrams can go really fast but it's engine is capable of making it go faster. Also, no tracking system can account for hitting a large, solid object at 70 mph. There's some lag time, even if just a few hundredths of a second, that makes shooting more difficult.

The other consideration is that going full speed across somewhat rough terrain can result in some maneuvers that would make the Duke brothers proud. It's very possible that the vehicle can be in a position that the turret just can't traverse far enough to stay on target.

[Inspector2311]

Good to know. Thanks.

[carlisimo]

And while a tank might bounce more because it's going faster, that's not really the same thing as above.  The stabilizers should compensate for extra speed, just as they do in a slightly faster tank.  Or just as they do when that tank moves faster due to gravity/roads/etc.

Some armored vehicles have their speed governed below their real capacity because the suspension can't keep up - the crew would be bounced around too much, even to the point of injury.  Not a great environment for lining up a shot. 

[CVB]

Yes, I had thought of that... but it presumes that every vehicle actually has a speed which exceeds the mechanical limits of its own stabilizers.  I was under the impression that modern MBTs could go flat out over most terrain and not exceed their stabilizers.  I could be wrong about that, but even so, one would think that 30th+ century vehicles could.  (Yes, I know, there's a lot of WWII type stuff in Battletech rules, LosTech, etc... that's a whole other discussion...)

It's not just the stabilizers, but main gun elevation and depression is very limited to keep the turret height (=target area) low. No gun stabilizer system can compensate a tank going up/downhill more than those limits without damaging the breech or turret internals, or smashing the barrel into the glacis plate.

[Inspector2311]

Both sound plausible.  That helps; thanks.

[Dayton3]

I get why a 'Mech could move faster if it foregoes attacking.  Not only is the pilot focusing completely on movement in order to get that extra speed out, but the 'Mech is also likely to be literally sprinting.  The arms and torso are swinging around with abandon in order to get that extra energy out, just as a sprinting humanoid would do, and that would preclude the normal operation of the targeting systems.

So far, so good.

But how can a tank sacrifice firing to go faster?  It has a separate driver and gunner, so it's not like the gunner is unable to fire because he's concentrating on making the tank go faster.  And while a tank might bounce more because it's going faster, that's not really the same thing as above.  The stabilizers should compensate for extra speed, just as they do in a slightly faster tank.  Or just as they do when that tank moves faster due to gravity/roads/etc.

So, my question: is there a logical explanation for why vehicles can sprint, or is it just a rules/balance thing?  I was going to house rule this in my campaign because it didn't make sense to me, but I figured I might as well ask if anyone knew of / could think of a logic behind this.

(Assuming, of course, that I've read the rules correctly and vehicles actually can sprint.)

Simple.   the same reasons for most things that happen in BT.

game balance.

[Colt Ward]

Both sound plausible.  That helps; thanks.

Oh it is easily that . . . vehicles have governors because as someone mentioned, if you go too fast you can risk damage to the vehicle itself with a untrained (and sometimes trained) drive going over rough terrain (might be why my APC got a divot in the hull) until they gain experience.  When you get to a warzone, one very quick unofficial modification is crews remove governors- or at least adjust them.  When it is a question of 'vehicle destroyed' or 'vehicle components service life shorten' most people pick shorting the service life.

FREX, when MLRS converted from the M577 to the M1068, the upgraded engine had no governor- it was something like a 50% HP increase.  The vehicle went from being able to hit 35 mph down a sloped road, covered in ice, with Siberian Express behind the vehicle to doing over 70 mph flat out over a sandy stretch . . . and at that speed, if there was ANY difference in the track tension the vehicle would waddle b/c 1 set of tracks would compete a circuit faster than the other side- faster you go the more noticeable it was when driving (another reason for governors).  But that vehicle had so much more power on hand, that when old crewers hit the breaks (which were improved) the rear of the vehicle would leave the ground.  They had Track Commanders breaking ribs on the hatch when their drivers slammed on the brakes.

In less than a year, that vehicle got a governor that topped it out at around 42 mph on a flat stretch and the brakes were relaxed, but by that time drivers had either learned to go easy on the breaks or suffered some extra counseling from the TCs.

And it was the first adjustment planned when the vehicle ended up in places like Iraq or Afghanistan.

MOST military vehicles, ships, and aircraft SOP is to only travel at 80% of speed- max- due to fuel consumption, maintenance requirements, and service lift of hull/components.

[Inspector2311]

suffered some extra counseling from the TCs.

Heh. "Counseling."

[CVB]

see FM 22-102

[Ollie124]

While stabilization is indeed limited by physics, there is an important factor people are forgetting about, the gunners are not stabilized.  I spent 2 years as a Bradley gunner, and there does get to a point where it is impossible to keep a sight picture or even keeping our face to the gunner's sight.  At which point, you are just holding on and trying to keep your head from pinballing around the turret.  Narrative-wise, I figure the same thing is going on when a vehicle sprints in Alpha Strike

[Colt Ward]

And TacOps sprinting- which is part of the reason they are not firing.

[Demiurge]

But how can a tank sacrifice firing to go faster?  It has a separate driver and gunner, so it's not like the gunner is unable to fire because he's concentrating on making the tank go faster.  And while a tank might bounce more because it's going faster, that's not really the same thing as above.  The stabilizers should compensate for extra speed, just as they do in a slightly faster tank.  Or just as they do when that tank moves faster due to gravity/roads/etc.

IRL there is actually a limit on what a tank gun stabilizer can compensate for.  It's not so much a maximum speed as it is a maximum amount of ride choppiness.  A gun barrel has a huge amount of inertia, and if it's getting thrown around too much there comes a point where the stabilizer simply cannot keep it on target.

I am reliably informed that this limit is often academic as the crew is likely being shaken too vigorously to perform well in the first place.

I think either of those works as a plausible explanation for what vehicle sprinting is; the vehicle is moving at a speed that the powerplant can deliver, but the suspension can't keep things smooth enough for either the fire control or the crew to work effectively.

[Colt Ward]

Having driven a armored vehicle across a open field at too fast a speed . . . yeah.

[CVB]

Problem: a vehicle of a given size and suspension type (say a 20t tracked tank) can move at 4/6, 5/8 or 8/12, only depending on the engine rating. Weapon (and stabilization) and chassis, suspension and controls all weigh the same. Why does one of them count as sprinting for firing purposes, one as flanking and one as cruising?

[nckestrel]

The engine rattles.

[Colt Ward]

because the guys who created the game did not care about vehicles, nor were they engineers.  SOME of that does not matter . . . FREX, the T&E is the same between a M249 and a M50 or Mk 19 . . . and all 3 of them have different weights and cyclic ratings.

[Demiurge]

Problem: a vehicle of a given size and suspension type (say a 20t tracked tank) can move at 4/6, 5/8 or 8/12, only depending on the engine rating. Weapon (and stabilization) and chassis, suspension and controls all weigh the same. Why does one of them count as sprinting for firing purposes, one as flanking and one as cruising?

If it helps, you can imagine that the weight allocated to the "engine" in both mechs and vehicles isn't going into the powerplant per se.  Some of it is going into beefier stabilizers for weapons, some of it is going into bigger shock absorbers or beefier structure to handle the higher loads of moving cross-country at higher speeds, and some of it is going into more robust myomer/transmissions to facilitate higher speeds and accelerations.  "Engine" is just a catch all term for the weight allocated to various mobility-enabling features needed for maneuvering at high speed during combat.

I'm sure this explanation breaks down seven ways from Sunday if you inspect it too hard though.

[pokefan548]

Also should note that in Classic, it's not "Moving" but "Cruising", and not "Sprinting" speed but Flanking" speed, which moves the same distance but you can fire. Technically, in Classic, vehicles can't even Sprint, instead having Overdrive as their "go super fast but can't fire" option. In other words moving normally is moving at the speed range where the engine is most efficient and everything works smoothly, whereas Flanking or "Sprinting" in Alpha Strike is just a matter of putting the pedal all the way down.

But, as a sweeping change, just like 'Mechs vehicles now have simplified Move/Sprint modes, and being unable to fire while moving at a 1.5x rate is simply a consequence of the system. Unsatisfying answer I know, but hey.