Bicycle Mechanics - 1996 Altus triple crankset - Hyperdrive C?

I have a weird triple crankset, where the big ring is actually only a 38t.....never seen one like that before.

Thinking down the road, what chainrings should I be looking for when those wear out?

Also, since the Altus FD was (I assume) designed to shift only up to the 38t ring, are there any current FDs that would make an easy replacement if this one goes out? (assuming I keep the rings all the same size as they are now).

Thank you,

A 38 big would be kinda rare, while Altus is not. I'm guessing it'd shift just fine up to 42 or 44 at least.
What rings to look for depends on your budget, and what you can find.
I've never been particular about it. 4/5 hole, bolt circle diameter, tooth count, price, silver or black - in that order of priority.

38t as the big ring? Are you sure someone didn't change the rings so they ended up with 2 center rings for the center and big ring? How many teeth are the other rings? i'm just curious. Seems like an odd max chain ring size.

I also imagine that the Altus derailleur being so common is just a standard off the shelf part designed to accommodate up to a 44t like the above poster said.

What are the size of the other 2 rings?

I have an odd combination of rings on my 2 bikes.
Originally, the cranks were 22-32-44.
They are now 22-32-36 & 22-32-38.
Long story, but with my riding conditions and a 12-23 cassette on one and a 12-21 on the other, it gives me 2 larger rings I actually use.

http://beatbikeblog.blogspot.com/2010/01/crank-cull.html

This is the exact crank -- it looks like rings are non-replaceable, so I'll probably just toss it and use one of my other cranks from the parts bin once it goes out.

38-32-24 = weird.

The FDER should still be good up to a 42-44T large ring.

The FDER for the original 28-38-48 on my hybrid actually worked OK for the 22-32-36. I had to mount it about 1/2" higher than the big ring so that it would clear the middle ring, when going to the granny..
For the most part, I ride the bikes on the middle ring as a 1X9.
The few times I do shift, there's no problem.

Okay, good deal.