I had a 50cc motorbike in my youth that needed to get to University and back, about 1000km away.
Off came the front wheel and then the bike was bolted to a fabricated hitch that bolted to the car's tow hitch where the ball normally went, using the original wheel bolt.
Yes the bit of hitch the bolt went through could rotate.
The chain was also removed just in-case the bike slipped into gear.
The rear tire was deflated a little to make it less 'bouncy' without the rider's weight on the bike.
Kinda like this, but with the front wheel removed and the wheel bolt, bolting the bike to the tow hitch.
That kept the nose down behind the car's trunk, out of the airstream.
And yes; how fast the bike could push the car was also 'tested'
(How 'The Vast Majority' can conclude that all that nose way up in the air and all that strapping down and worrying is better or faster than simply removing/replacing the front wheel is one of 'Life's little mysteries' to me!?
Then again, there are ...er... people who can't reverse trailers and sit waiting for someone for hours and great expense when they have a flat!??)
If you want aero; the same might be done with bicycles but removing the chain is unnecessary thx to the freewheel hub.
I'd definitely deflate the rear tire some to compensate for the fact that the rider's weight isn't on the bike, else it'll be VERY 'bouncy'!
If the bike has a rear suspension it's less likely to be airborne as often, but airborne cuts rolling resistance!
