Piecemeal armor rules say plate arms have an armor penalty of -7, and that when combining multiple pieces you take the worst armor penalty, and that a suit of full plate includes the plate arms. Thus I'm confused about why the armor penalty for a full set is only -6, and not -7.


3 Answers 3


Full-plate implies a single set of armor, each plate carefully devised to fit against one another and fit the intended owner’s body. Plate armor was custom-made and when made well, frequently was actually rather flexible and wearable, despite its weight and stiff protective areas.

So it makes sense that putting together a bunch of piecemeal armor would be more cumbersome than the custom-fitted armor.

What makes zero sense is that you get all of that ACP from just one piece, as Squish points out. Design-wise, taking the worst ACP from the bunch rather than having some additive system is just bizarre.

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    \$\begingroup\$ So if instead you take random bits and pieces more or less in your size and wear them all you get -7 armor class penalty, but if you own a full set and just take off pieces and wear say only the breast plate for a while and then put everything back together it should come out back as the original full plate, yes? - Followup: the -7 comes only from the plate arm pieces. If a gladiator wore only the arms should he then get the full -7 armor class penalty for a +1 bonus to AC? \$\endgroup\$
    – Julix
    Feb 24, 2014 at 6:28
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    \$\begingroup\$ If you were wearing a full suit of armor it wouldn't be piecemeal anymore would it? The penalties are what they are, it may not make sense all of the time but that's just how roleplaying games are. If you think that the penalty should be different, ask your DM to have it changed (or change it yourself if you happen to be DM). \$\endgroup\$
    – Mr Tumnus
    Feb 24, 2014 at 12:07
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    \$\begingroup\$ Just asking to make sure that I didn't miss anything that's already officially established. \$\endgroup\$
    – Julix
    Feb 24, 2014 at 22:13

There's no apparent particular reason why the ACs should be that way, and they probably shouldn't be. On a personal note, those rules seem poorly balanced. If you're wearing only the arm pieces, a -7 (especially from a suit that is yours) is a ridiculous ACP.

Are you wearing the full arm from shoulder to fingers, or just using them as ad-hoc bracers?

In any case, I'd say a -2 ACP would be your absolute maximum penalty. Even then, that seems a little steep.

ACP is suppose to represent the effects of weight, stiffness, difficulty of movement, etc inside a given suit of armor. Given that the arm pieces of full plate could be considered one of the more awkward parts of the suit I'd personally rule something along these lines:

Start from a base +1 AC / -2 ACP

Are you proficient with that type of armor?

  • Yes : ACP does not change.
  • No : ACP increases by two. (Total of -4 ACP)

Is the armor masterwork?

  • Yes : ACP reduces by 1
  • No : ACP does not change

So, if you're not proficient with Full Plate, you'll have a +1 AC -4 ACP. If you are proficient and it's masterwork, +1 AC -1 ACP.

Now, I haven't read the entirety of that supplement. So if ACP is playing a big role in your campaign and everyone is suffering from crazy ACP penalties, you may need to tweak the numbers a little. But not up to -7 for one set-piece.

Question from comments :

Imagine trying to disarm a trap wearing those arms though... I could see how wearing heavy armor except arms you should be able to disarm almost unhindered if it's something like a trapped lock. Fine dexterity tasks do deserve a big penalty for gauntlets, forearm piece, elbow piece, and shoulder pieces... - and I could almost see how it being connected to a whole body armor would make all the pieces more stable... they don't wobble around as much then?

Answer: Mechanically, in this scenario, that's an outlying situation. Most classes who are proficient with plate do not have ready access to disarm traps as a class skill, and are typically unlikely to pick it up. Being non-proficient with plate (like rogues are) leaves you at a -4 ACP anyway. Which is an extra 20% chance to mess up on a straight d20 roll. Also, remember, these are fantastical heroes who regularly defy the odds anyway.

Realistically: Plate mail fingers come in a wide variety of flavors. Outside of fantasy I've never seen Sauron-fingers. (Tubes of metal wrapped around your digits.) Most plate either ends at the top of your hand, with a simple plate of metal sitting on the back of your hand. OR has lobster-plates extend down over the TOP of your fingers. A leather, or chain mail, glove is then worn on the hand for protection. So, really, the plate mail isn't getting in the way as much as you would think.

Also considering you aren't wearing virtually any of the armor, most of the associated skill penalties probably shouldn't even be applying. Aside from fine-dexterity skills. (Such as the disable skill above.)

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    \$\begingroup\$ This doesn't appear to answer the actual question as to why the full plate penalty is -6 \$\endgroup\$
    – Wibbs
    Feb 24, 2014 at 13:22
  • \$\begingroup\$ @Squish We expect answers to actually independently answer the question given. Further elaboration is welcome, so long as it actually comes with an answer directly addressing the question asked. I've tinkered with your first paragraph to provide what I think is your stance so this actually directly responds to the question asked. Please check my edit and edit it further if you'd like. \$\endgroup\$ Feb 24, 2014 at 13:27
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    \$\begingroup\$ @Phil : The answer was "because it's poorly balanced", I spelled that out pretty plainly at the beginning. There is little-to-no math, or even good in-game reasoning, behind a design decision as punitive as that. JonathanHobbs : Thank you, that is worded much better. :p \$\endgroup\$
    – Squish
    Feb 24, 2014 at 13:36
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    \$\begingroup\$ I would think plate arms without the rest of the armor would be more of an inconvenience as they aren't being supported by the main part of the armor. \$\endgroup\$ Feb 25, 2014 at 4:51
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    \$\begingroup\$ @LorenPechtel They are more of a physical inconvenience without support than they would be with it, but are they more of a physical inconvenience than an entire 50 pound suit of armor? (the arms are 10lb) \$\endgroup\$ Feb 25, 2014 at 9:26

AC Penalty is made to reflect the difficulty of performing certain actions while wearing different types of armor. In a full suit of plate armor, the check is -6, but in just a set of plate arms, you get -7.

This suggests that wearing a full set of armor is less cumbersome than wearing just part of it. Which, for a well-crafted suit of armor, makes sense. A full suit of plate armor is custom-made to balance with the wearer. It's still a big heavy suit of armor, but it's tailor-made so that it all balances together.

Whereas simply putting on the Plate Arms does not give you that balance between the different armor parts - it puts extra weight on your arms, while leaving your legs unencumbered, something that throws your whole body off-balance.

The -7 is there to indicate the difficulty in wearing this unbalanced set of armor, while the lesser -6 indicates a full set of armor that is properly balanced to the wearer.

This is all, of course, up to the GM's interpretation - especially considering wearing part of a full set, rather than a section off of someone else's armor or a piece of armor found off of someone else.


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