Do speed changes affect gyro ball?

Question

Do stat drops in speed, like by sticky web or rock tomb affect power of gyro ball? Or do only base speeds count? Also, please tell if paralysis changes any mechanics. That question is unclear.

Answer 1

Base Power = 25 × min(6, (Target's Current Speed / User's Current Speed))

(Gyro Ball's Base Power Formula)

Source

According to Bulbapedia, Current Speed counts, meaning Speed drops affect Gyro Ball. It is possible for a Pokemon to be so slow (or the opponent so fast) that stat stages don't boost Gyro Ball's power, because it maxes out at 150 Base Power. Here is some calculations:

With Neutral Speed:

0 Atk Bronzong Gyro Ball (38 BP) vs. 0 HP / 0 Def Abomasnow: 96-114 (34.1 - 40.5%) -- guaranteed 3HKO

With -1 Speed:

0 Atk Bronzong Gyro Ball (57 BP) vs. 0 HP / 0 Def Abomasnow: 144-170 (51.2 - 60.4%) -- guaranteed 2HKO

With Paralysis:

0 Atk Bronzong Gyro Ball (38 BP) vs. 0 HP / 0 Def Abomasnow: 96-114 (34.1 - 40.5%) -- guaranteed 3HKO

Source

It seems that paralysis doesn't affect Gyro Ball's power but being slower via stat stages (or you opponent's stat stages being higher) does. I used Bronzong because Gyro Ball's Power isn't maxed out against my dummy Pokemon, Abomasnow, so we could tell the difference if stat stages affect Gyro Ball. If your Pokemon with Gyro Ball is slow enough, it doesn't make a difference. :P

Hope I helped!

Note from Meta Ridley:
Iron Ball affects the power of Gyro Ball as well, look at these calcs:
With Iron Ball;
> 252+ Atk Bronzong Gyro Ball (111 BP) vs. 252 HP / 252+ Def Abomasnow: 266-314 (69.2 - 81.7%) -- guaranteed 2HKO

And without Iron Ball;
> 252+ Atk Bronzong Gyro Ball (54 BP) vs. 252 HP / 252+ Def Abomasnow: 132-156 (34.3 - 40.6%) -- guaranteed 3HKO

Comments

Both the answers conflict on the stat changes parts. Could you please confirm which is right?

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Yes; CinccinoFloof tested on a Ferrothorn, which against Abomasnow, already has max Gyro Ball power (Gyro Ball's has a max power Cap). That happened because Ferrothorn has one of the slowest speed tiers. I tested with a faster Pokemon so that Gyro Ball's power wasn't maxed out and saw that stat changes to both opponents affect Gyro Ball's power as well. The only reason Paralysis doesn't affect Gyro Ball's Power is because Paralysis affects turn order, not the Speed Stat itself, like Stat Stages do. :P

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Paralysis affects the speed stat, not the turn order.
https://bulbapedia.bulbagarden.net/wiki/Paralysis_(status_condition)

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I meant it affects the Speed Stat only for the Purposes of Turn Order; the Speed Stat is not counted as halved at any other time except determining turn order. If it directly halved the Stat, Gyro Ball would be affected by it. :P

Answer 2

In this video, we explored some of the mechanics of Gyro Ball, starting out with a Shuckle at -6 speed with Iron Ball, then later on shifting to -6 speed and paralyzed (but with the item slot free for something else). In particular, this test uncovered the mechanic that if a Gyro Ball user has exactly 0 speed, the move is treated as 1 power regardless of the opponent's speed.

Shuckle is obviously much slower than the other Pokemon involved in the test, so if not for this special-case mechanic, its Gyro Ball would have very high power: in that sense, this serves as a compelling test case for the mechanic that's easy to distinguish from any other result. The only way the speed stat can be treated as 0 is if the game is taking both the stat "boosts" and one of paralysis or Iron Ball into account (whichever of the two is in effect at the time), and the fact that the damage output is so low proves that it is indeed defaulting to that 1-power case, except for one turn at 5:22 after the Iron Ball had been removed but before Shuckle got paralyzed.

Comments

Gyro Ball's power is set to 1 after getting your speed that low to avoid dividing by 0 and potentially crashing the game  or making any other problems occur. :P

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Interesting. I believe it is to avoid division by 0.

Answer 3

No speed changes

0 Atk Solgaleo Gyro Ball (14 BP) vs. 0 HP / 0 Def Chansey: 102-121 (15.9 - 18.8%) -- possible 6HKO

+6 speed user

0 Atk Solgaleo Gyro Ball (3 BP) vs. 0 HP / 0 Def Chansey: 22-27 (3.4 - 4.2%) -- possibly the worst move ever

+6 speed target

0 Atk Solgaleo Gyro Ball (59 BP) vs. 0 HP / 0 Def Chansey: 426-502 (66.4 - 78.3%) -- guaranteed 2HKO

-6 speed user

0 Atk Solgaleo Gyro Ball (59 BP) vs. 0 HP / 0 Def Chansey: 426-502 (66.4 - 78.3%) -- guaranteed 2HKO

-6 speed target

0 Atk Solgaleo Gyro Ball (3 BP) vs. 0 HP / 0 Def Chansey: 22-27 (3.4 - 4.2%) -- possibly the worst move ever

paralyzed user

0 Atk Solgaleo Gyro Ball (14 BP) vs. 0 HP / 0 Def Chansey: 102-121 (15.9 - 18.8%) -- possible 6HKO

paralyzed target

0 Atk Solgaleo Gyro Ball (14 BP) vs. 0 HP / 0 Def Chansey: 102-121 (15.9 - 18.8%) -- possible 6HKO

tailwind: Showdown!'s damage calculator doesn't have this...
swift swim user:

0 Atk Solgaleo Gyro Ball (7 BP) vs. 0 HP / 0 Def Chansey: 51-61 (7.9 - 9.5%) -- possibly the worst move ever

swift swim target

0 Atk Solgaleo Gyro Ball (29 BP) vs. 0 HP / 0 Def Chansey: 211-249 (32.9 - 38.8%) -- 99.6% chance to 3HKO

choice scarf user

0 Atk Solgaleo Gyro Ball (9 BP) vs. 0 HP / 0 Def Chansey: 66-78 (10.2 - 12.1%) -- possible 9HKO

choice scarf target

0 Atk Solgaleo Gyro Ball (22 BP) vs. 0 HP / 0 Def Chansey: 160-189 (24.9 - 29.4%) -- 100% chance to 4HKO

slow start user

0 Atk Slow Start Solgaleo Gyro Ball (14 BP) vs. 0 HP / 0 Def Chansey: 51-61 (7.9 - 9.5%) -- possibly the worst move ever

slow start target

0 Atk Solgaleo Gyro Ball (14 BP) vs. 0 HP / 0 Def Chansey: 102-121 (15.9 - 18.8%) -- possible 6HKO

source
So apparently every kind of speed change affects gyro ball's power except paralysis, slow start, and maybe tailwind.

Comments

That's just according to the Showdown calculator, which isn't fully accurate in that regard.

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This was the most accurate damage calculator I could find. Is this answer wrong?

Answer 4

So I played around a bit with this Damage Calculator, and it seems that speed decreases on your side/speed increases on the opponent's side do not affect Gyro Ball's damage output, but speed increases on your side/speed decreases on the opponent's side will reduce Gyro Ball's power. Also, paralysis has no effect on Gyro Ball's power whatsoever.

So running Sticky Web or another speed-reducing move and Gyro Ball on the same team is not a smart idea, but your opponent's Sticky Web will not buff your Gyro Ball.

If you're curious about what Pokemon I tested this with, I used a Ferrothorn (which commonly runs Gyro Ball) and an Abomasnow (the default setting).

Comments

So it basically only sees whether it can decrease the power after calcs?

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Yeah. Gyro Ball has a set amount of damage rolls as well as HP loss percentages at the top of the page when you click on Gyro Ball, but if you put the Gyro Ball user at +1 Speed or the opponent at -1 speed, you can see the damage rolls and percentages change, which is how I got my answer.

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Gyro ball does take the user's speed drops and target's speed raises into account. However, if the target's speed is already 6 times higher than the user's, then gyro ball's base power maximizes and won't go higher.