Need more information.
What size are the wheels on each bicycle? 700, 26", or 650?
Schrader or Presta valves on the wheels? or tubeless?
Will the riders of the two bicycles be stopping for pie and coffee somewhere along the route?
Will the riders be dressed in aero 'roadie' gear or standard loose-fit MTB gear?
Wrap-around shades or standard Ray-Ban sunglasses?
Clipless, platform, or strapped-in pedals?