Weight of Steel

Weight of Steel is a lightweight armor-weight mod
It slows the player based on the actual weight of equipped armor.

Features

• No vanilla Slowness effect.
• Speed reduction is applied through the player's real movement speed logic.
• Armor tooltip shows the weight used by the calculation.
• JSON config supports global tuning and per-item overrides.
• Modded armor can be tuned by exact item id such as modid:custom_chestplate.

How it works

The mod calculates armor weight from the equipped pieces and converts it into a movement speed penalty.
By default it uses armor stats such as armor, toughness, and knockback resistance.
If an item has a manual override in the config, the custom value is used instead.

Configuration

config/armorweight.json

{
  "showTooltip": true,
  "weightToSlowdown": 0.013,
  "maxSlowdown": 0.35,
  "toughnessWeight": 0.5,
  "knockbackWeight": 8.0,
  "itemOverrides": {
    "minecraft:netherite_chestplate": {
      "useCustomWeight": true,
      "customWeight": 25.0
    },
    "modid:custom_helmet": {
      "useCustomWeight": true,
      "customWeight": 7.5
    }
  }
}

Notes

• The mod is designed to work with modded armor too.
• New armor entries are synced into the config after launching the game.
• If the config becomes invalid, the mod recreates it and keeps a backup.