Modern pla is NOT brittle - sheesh, where do people keep getting this crap from ?
It is stiffer than abs, but it's not brittle. If you hit it with a hammer it dents, it does not shatter.

Anyway polymax is ideal, stronger and tougher than abs in all aspects.
personally I'd try the polyplus first - that;s pretty good too.

But unless your gears are going to get warm, then normal pla should be fine.

As far as any taulman nylon goes - good luck :-)
I've never come close to getting a decent print from any taulman filament.
And given that pet and polycarbonate are both cheaper than taulman nylon (which comes on weird little reels with tiny holes that don't fit most peoples reel holders) and much easier to print with.

These days nylon would always be a last ditch filament for me. Unless I could afford the MyMat stuff.