Is this Monk’s Robe magic item conversion balanced in 5e?

Question

In Pathfinder, there is a magic item called the Monk’s Robe.

I like the idea, and have tried to convert it to D&D 5e, but I don’t know if my conversion is balanced. My conversion of the item is below:

Monk’s Robe

Wondrous item, uncommon

1 lb.

When worn, this simple brown robe confers great ability in unarmed combat. The wearer’s Martial Arts die increases by one die size, and their movement speed increases by 5 feet.

Unless it is already higher, the wearer’s unarmed strike damage uses a d4 for damage. If the wearer’s Martial Arts die is a d10, it becomes a d12.

Is this Monk's Robe magic item balanced for D&D 5e?

Answer 1

It seems a bit underpowered for a Rare, Attuned item.

I will simplify it a bit, because while the effect differs in some levels, for the most part it boils down to the Martial Arts die being one step higher and the Unarmored Movement being an extra 5 feet.

Damage: Stepping up the die (d4->d6, d6->d8, etc.) confers an average damage increase of 1. So for the most part the item will grant 1 extra damage (or 2 on a crit). That is worse than an Uncommon +1 weapon, which adds +1 to both damage and attack rolls. It is also worse than the Uncommon Bracers of Archery, which grant +2 damage when you use bows.

Movement: Adding +5 is a bit of an odd one, however in higher levels (when they get Rare items) the monk would be significantly faster than the rest of the party anyway, so 5 feet extra is of limited use.

So I think you could get away with making this item Uncommon, in the vein of "Bracers of Archery" in which case it seems to be balanced.

On non-monks, the main feature would be the extra 10 feet Unarmored Movement, which could be pretty useful for casters who don't wear armor, but still not worth a Rare, Attuned item .