Are MK7 and MK8 (5mm and 8mm) drive gears interchangeable?
In short, no. The drive gear has a different outer diameter, which means changing a lot of other parts on the whole extruder so the filament and hot end is in the right place.
Even w bowden extruders?
Well, the filament path moves about a mm, so yeah.
Yea but will the filament not grip, or is it just the filament path that changes?
Either the filament will be very stressed or the filament won’t be gripped if the filament path isn’t moved for the different pulley.
There is no drop-in swap. You either keep the same kind of part or change several parts. There isn’t a way around this.
Oh ok. Thanks man.
It depends on your extruder design… If the filament path is constrained too much then it won’t work as well. Some of the more open designs should allow the filament to flex enough without binding, but it’s usually best to print out a new extruder that fits properly.