Different size disc's on 2 gang disc harrow???

[BullDAWG]

I have an old pull type disc harrow with 18" disc's. I replaced one gang with new blades and now wanted to replace the other gang, but after I have had my fields chisel plowed I go to the axles deep on this implement. I was wondering if it was even thinkable about putting 20" or 22" disc's on the front gang instead of the 18" thats currently on both the front and rear gangs now. I can't put 20 or 22 in on the rear unless I notch out the frame and then I personally would add extra support in the notched area. But I was just wondering if different sized disc's could be even an option till then or am I crazy for even thinking this? I can adjust the drawbar to add more or less pressure on rear gangs so I was thinking it could work. I was just asking if anyone has ever heard or seen this before? If it doesn't work I would then have to buy same size for rear and just notch the frame (3' angle iron) about 1/2" depth triangular shaped notches to allow clearance of larger disc's. I'd then add 1' of 2" angle iron to notched area and weld them on to add extra support in the spots that were notched.

[Eugene]

Since you are dragging the disk harrow's axle in the dirt, going to a larger diameter disk more than likely won't help.