Power-to-weight ratio (Acceleration rate)

Mobility stats of your tank are heavily interconnected.
To understand acceleration rate properly, make sure you also know what terrain resistances are.

What is raw power-to-weight ratio?

Power-to-weight ratio, also known as horsepower-per-ton (hp/t) is your tank’s raw acceleration rate.

This is how quickly your tank is able to accelerate up to its top speed.

You can calculate your tank’s hp/t rate by this formula:
Engine power/Tank weight (tons) = Power-to-weight ratio

For example, the AMX CDC weighs 33.92 tons, and has a 1380 horsepower engine:
1380hp / 33.92t = 40.68 hp/t rate

(Note that these numbers are rounded. To get the most accurate hp/t rate, don’t round the number.)

Raw vs effective acceleration rate

These are 2 completely different stats, but they are closely related.

Raw acceleration rate is discussed above, its your tank’s base engine power, divided by your tank’s weight, giving the raw acceleration rate of your tank.

Effective acceleration rate is what really matters on your tank. This is the true acceleration rate of your tank, and it takes into account the terrain resistances of your tank, with the raw acceleration rate, to give the effective/true acceleration rate of your tank on each different type of terrain.

The difference between these two really depends on your tank’s terrain resistances. On some tanks, your effective and raw acceleration rate are the same, other tanks may never have the exact raw acceleration rate in game due to their terrain resistances.

What is effective acceleration rate?

Effective acceleration rate, also known as effective horsepower-per-ton or effective power-to-weight ratio, is true acceleration rate of your tank on different terrain types.

This is how quickly your tank actually accelerates, as it takes into account the terrain resistances of your tracks, and factors this into how effective your acceleration actually is.

You can calculate your tank’s effective acceleration rate using this formula:
Raw acceleration rate / Terrain resistance = effective hp/t.

So for example, the AMX CDC has a 40.68 raw hp/t rate, ground resistances of 1.1 on hard terrain, 1.2 on medium terrain, and 1.6 on soft terrain.*

So on hard terrain, the AMX CDC’s effective acceleration is 40.68 / 1.1 = 36.98 hp/t
On medium terrain, it would be 40.68 / 1.2 = 33.90 hp/t
On soft terrain, it would be 25.43 hp/t

*Note that WG’s in-game terrain resistance numbers translate to a factor. So in the AMX CDC’s case, 100 = 1.1, 92 = 1.2, 71 = 1.6.
You can find these factors on BlitzStars Tank Compare tool.

(While you can find effective acceleration rates on BlitzHangar, its reccommended to calculate them for yourself, since BlitzHangar is very outdated, and some tanks have completely different stats to what is shown on Blitzhangar.)

Mobility vs terrain performance

-If your tank is fast on roads and paved areas (hard terrain), but it much slower when going off-road (medium terrain), there’s likely a very large difference between your hard and medium terrain resistance.
(For example, the Keiler has a terrain resistance on hard terrain of 1, but on medium terrain its 1.5; so it slows down much more when going off road, and the difference between the two terrain types is very noticeable to the player.)

-Good ground resistances will make your tank accelerate faster than the in-game stats (raw acceleration) seem to show.
-Poor ground resistances will make your tank accelerate slower than the in-game stats (raw acceleration rate) seem to show.

-Soft terrain is water. It causes your tank to have the worst possible mobility performance. When you drive in water, you generally do it knowingly, as there is a visual differentiation with this terrain type. Hard and medium terrain are much harder to differentiate from each other.

Does raw acceleration rate even matter?

Since terrain resistances just change a tank’s actual acceleration rate, does the raw accelerate even matter on a tank?

Yes it does, having a strong raw hp/t rate allows the tank to still accelerate relatively quickly, even if poor terrain resistances are holding it back.

-For example, the KV-5, AMX CDC, T95E6, AMX M4 54, 53TP, Tiger 1, etc., all have very strong engines and good raw acceleration rate, but terrain resistances reduce their actual acceleration rate.
These tank’s don’t accelerate as fast as you expect, yet they aren’t as slow as their effective acceleration rate seems to convey.

This is due to these tanks having a good raw acceleration rate. Their strong engines still allow them to accelerate well, though it doesn’t quite feel as fast as the stats show in game, its still not quite as slow as the effective hp/t seems to show.

-For example, the KV-5 only has an effective hp/t rate of 8.76 hp/t on medium terrain, however, its still able to fairly easily achieve its 40km top speed. This is due to its strong engine and raw hp/t rate of 14.0
-In the case of AMX CDC, this tank’s strong 40.68 raw hp/t rate is what makes it feel even faster accelerating than a leKpz M41 90mm, even though its effective hp/t rate is actually less than the leKpz.

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