Off road rating and weight when it comes to risk of bogging

[rocketman]

The off road rating for AFVs, does it take weight into account when it comes to bogging down, for example in muddy conditions? For example, a M10 tank destroyer has the same off road rating as a Tiger I, but weighs almost half as much. I would think weight would be a significant factor and risk for bogging down, but with these two factors as they are it is hard to determine more exactly what level of risk there is. I would assume that the M10 would be safer to run across a muddy field, but to what extent? Can someone shed some light on this?

[MikeyD]

I recall long ago Charles, while commenting on something else, mentioned typing the ground pressure (flotation) numbers into vehicle stats. So weight and ground pressure are definitely in the mix. A vehicle you'd expect to be terrible at crossing boggy ground is terrible at it, and a vehicle you'd expect to do better will do better.

[Vanir Ausf B]

Keep in mind that the 1-5 bar rating in the UI is an approximation. It's much more granular "under the hood".
 

Quote

Charles is only using ground pressure with a "gamey" modifier to penalize vehicles which were known for having poor weight distribution (nose heavy, such as the JPz IV). However, I convinced him to give the German vehicles with interleaved wheels a slight bonus to conform with the spirit of MMP.

As far as I know... ground conditions + vehicle ground pressure + vehicle bonus/penalty + crew quality = chance of bogging.

https://community.battlefront.com/topic/106892-tank-off-road-performance-tests-and-possible-wackiness/?do=findComment&comment=1485259

Edited December 31, 2021 by Vanir Ausf B

[rocketman]

"More granular under the hood" - that's the BFC motto, right?
That's what I suspected, so I guess the best way to know is to do some research combined with "common sense" and a healthy dose of experience from playing the game.

Other factors that come into play might be: width of tracks and width of vehicle - to spread out ground pressure. Any other suggestions?

Edited December 31, 2021 by rocketman

[Vanir Ausf B]

PSI is weight divided by track surface area.

Width of vehicle is not a factor.

Edited December 31, 2021 by Vanir Ausf B

[transporter]

Someone who has more info than I do can check the width of the Tigers track vs the M-10.  A wider track helps spread out the weight making a lower "footprint" weight per square inch.  This is one of the reasons the T-34's did so well in soft ground conditions.

[Erwin]

"...Charles is only using ground pressure with a "gamey" modifier to penalize vehicles which were known for having poor weight distribution (nose heavy, such as the JPz IV). However, I convinced him to give the German vehicles with interleaved wheels a slight bonus to conform with the spirt of MMP. I know from first hand experience that the science behind MMP is solid.

As far as I know... ground conditions + vehicle ground pressure + vehicle bonus/penalty + crew quality = chance of bogging. I also thought that speed had something to do with it, but it turns out that is not the case. Seems to be one of those things that was planned/discussed, made it into the manual, and has remained there even though it never was coded. I'll get that removed.

Steve"

 

[Sgt.Squarehead]

Reckon dodgy transmissions (Panther, this means you!   ) should be factored in too.....Significantly increased chance of becoming Immobilized after bogging.

[Drifter Man]

I've been testing the bogging probability of different vehicles by driving them Fast for 1000 meters over clear terrain (grass) in damp condition, with regular crews. I also tried to correlate it with ground pressure data - it worked well for US-made vehicles for the most part, where I have data from Hunnicutt, but the rest is all over the place. I don't have good ground pressure data for British, Soviet and German tracked vehicles and what I find on the web is often contradictory/unreliable.

Bogging chance	Off-road rating	Vehicles
< 4%	5	Marder I
4% - 6%	5	Marder IIIM, SdKfz 135/1, FlakPz 38(t) SU-76M Universal Carrier, Bren Carrier, Loyd, Jeep Humber III LRC
6% - 9%	4	Panther, Tiger, King Tiger, Jagdpanther, Jagdtiger, Nashorn Flammpanzer B-2(f), Marder II, Grille, Wespe, Hummel, Wirbelwind T-34-76, IS-1, IS-2, SU-85, SU-100, SU-122 M7B1 HMC/Priest, Crusader III AA, Stuart III Stuart III Recce, Stuart Kangaroo, Priest Kangaroo German AA halftracks, PSW 231, 233 2.5ton 6x6 Deuce, Studebaker US6 BA-64
9% - 11%	3	Pz IIL, Gw. 39H(f), Ostwind, Mobelwagen T-34-85, ISU-122, SU-152, ISU-152 M8 HMC, M18 Hellcat, M12 GMC Sherman V (M4A4), Sherman VC Firefly, Cromwell, Challenger, Stuart V, Sexton US-made halftracks (incl. mortar, AA, Lend-Lease, GMC)
11% - 13%	3	Pz III, Pz IV, R-35, Hetzer, JPz IV M4/M4A1/M4A2/M4A3 Sherman, M4A3(75)W, M4A1(76)W, M4(105), M5A1 Stuart/Stuart VI, M10 GMC/Wolverine/Achilles, Sherman IC Firefly, Churchill M8 Greyhound, M20 Armd Car
13% - 15%	2-3	JPz IV/70(V) JPz IV/70(A), Valentine M4A2(76)W, M4A3(76)W Daimler Dingo, Daimler Mk II, Humber IV, Staghound, White Scout Car, GAZ 67
> 15%	2	Elefant* PSW 222, 223 GAZ MM

 

*Elefant has off-road rating 3 but performed very poorly in tests.

Fully tracked vehicles only. Blue = American, Green = Commonwealth (can be US made), Red = Soviet (incl. some British and US made), Grey = German

Edited January 8, 2022 by Drifter Man

[Drifter Man]

On 1/1/2022 at 7:20 AM, transporter said:

Someone who has more info than I do can check the width of the Tigers track vs the M-10.  A wider track helps spread out the weight making a lower "footprint" weight per square inch.  This is one of the reasons the T-34's did so well in soft ground conditions.

M10 GMC: 29.6 t (in game), 16.56" track width, 147" ground contact length, 92.4 kPa ground pressure. Measured bogging chance ~11%

Tiger (Pz VIE): 56.9 t (in game), 725 mm track width, 3610 mm ground contact length, 106.6 kPa ground pressure. Measured bogging chance ~8.5%

The "gamey" bonus/malus adjustments quoted in the posts above could explain why I am not getting very consistent curve of bogging chance vs ground pressure. Most of the grey dots below the main line are the German big cats and their derivatives and the green dots are Cromwell/Crusader/Challenger. Meanwhile, the grey dots above the main line are Pz IV, JPz IV.