If it doesn't have a specific DC current setting, it's most likely a CT type and won't measure DC. I have a clamp meter that measures DC but it's a specific setting on the dial, and that meter cost about 3x as much as the "regular" clamp meter.
I'm looking at the ones used in solar systems (those 60V 100A ones) and not at the clamp meter tools.
They have a little blue plastic square that closes on the positive wire.
Do you know of any place that sells 20mm front hub for dual discs?