Cycling.

[chirpychippy]

and a lovely job Bob!

Can you do a version where they mount to the tow bar, then you can just drag the cycles along behind the car, like a trailer?

I probably could "Heath Robindon" something together. My concern would be the bearings in the back wheel, im sure they would self destruction at 70mph for extended period's!

 

[Brigadier]

When I do this I have a double glazing packet with a hole drilled in it and a hair elastic threaded through. I stick the packet between the pads and wrap the bobble over the caliper to keep it in place. Accidentally squeezing the brake as you load the bike up is a right pain in the backside if there isn't anything keeping the pads spaced

Mine came with a shim, to keep the pads apart when the wheel is out.

You should just rig one up, as Robin suggested.

 

[johnny2007]

When I do this I have a double glazing packet with a hole drilled in it and a hair elastic threaded through. I stick the packet between the pads and wrap the bobble over the caliper to keep it in place. Accidentally squeezing the brake as you load the bike up is a right pain in the backside if there isn't anything keeping the pads spaced

That's a good idea to avoid accidentally close all the caliper and lose oil.
In fact, any time a wheel is removed, pads should be pushed open so they can then sit properly when wheel is put back.
Rather than pump the brakes after refitting the wheel, go very gently whilst spinning the wheel.
That allows the pads to register properly and not rubbing on the disc.
On bikes the pads open so slightly that any imperfection in caliper alignment or disc position (or warping) can cause rubbing.