Nice motorbike designs

I use this technique to make small grid escape pods for my large grid ships.

that regular door... no means no bro. No amount of wiggling will convince it to let you in

Although this isn't quite the angle you were testing, another option is to use blocks with wonky collision boxes (like the "Light Armor Panel Slope," among others) to set up an air lock without even using doors. Two of them would give you a full Large Block (or 5x5 Small Blocks) worth of clearance. Just sayin'.

8:50 Wasn't turning well because the front wheels had no friction.

What if you turned stearing off on the rear?

Try to build a boarding drone, one able to fit into a regular door. Also, wheel's collision box is larger that the wheel's model, that is why 2 blocks wide rover didn't fit into the smallest door

any advice on the mono wheel?