Is there any reason you couldn’t use a brushless drill motor/gearbox (and the control circuitry and batteries) instead of using hobby brushless motors? I would assume since drill motor/gearbox combos put out more torque, you dont need as big of a ratio for the drive/wheel gears so you should still be able to get good speed.
I have just been doing the math and I can get a brand new brushless dewalt or makita drill on craigslist for ~$75-90 (without the batteries) and then I can just use my milwaukee drill batteries (with a 3d printed adapter), or get lipos to power them. And just use the control circuitry already in the drill to run it. The only downside I can see is that it would not have braking, which is not a really big deal as I could just make a manual brake like this: https://www.youtube.com/watch?v=vyqJuUkimhs
Is there anything wrong with this? Has anyone else tried this?