Heavy Duty Cradle Modular BaseThe Heavy Duty Cradle Modular Base includes everything you need to securely mount your bikes rear wheel except vacuum cups. You must already own one or more Mount Evo vacuum cups to buy a modular base. The Heavy Duty Rear Wheel Cradle is our upgrade rear wheel carrier designed specifically for large rear wheels or heavy e bikes. It comes as standard with our E Solo rack but makes a great upgrade for Solo or Duo users. For all the info you need on the