Disk brake balance?

I got myself a nimbus oracle 24" with disk brake over Christmas because of a sale unicycle.com we running. Didn’t get to ride it much because of the bad weather till recently.

Now I have taken it out, and I am having huge issues with it. I have an existing Koxx colossus 24" muni that I really like. But the issue with the Nimbus is that I feel like I keep having balance and control issues. I feel like the disk brake is perhaps affecting my balance and that I am leaning to one side. Never had any issues riding my other unicycles.

They have similar tires, koxx->duro 24 x 3.0 razorback, and nimbus 24x3.0 duro wildlife.

I replaced the cranks, because my koxx has 140mm and the nimbus 150mm, and thought maybe that was the cause, but that hasn’t made any difference.

Is there something else going on or is this is all in my head because it seems that the disc shouldn’t affect balance that much?

I do hear a rubbing sound when I ride, so perhaps something is wrong with the disk?

The disc brake has no influence on side balance. And as long as you’re nor braking, it has absolutely no influence on anything. The only thing I can imagine is: The oracle has an inboard disc and thus, an unsymmetrical hub. So your wheel should also be laced up unsymmetrical so that the rim/tire sit in the middle of the frame. You could check if your tire is in the middle of your frame and has the same amount of clearance to each side.

What can also cause issues with side balance is wrong saddle heigth. If it is to high, you may tend to lean to one side.