“Thanks to the huge variation of bikes out there, we ask a lot from our bike racks. They need to fit everything from 20mm to 5″ wide tires, frames of vastly different shape, and all without interference between multiple bikes. Because of that, most racks top out at four bikes maximum, though vertical racks have started to get more popular because of this very reason.
Vertical racks, like the ALTA SIX work by supporting the front wheel with a basket, and then a lower tie down strap secures the rear wheel. By tilting the front wheel slightly, the handlebars don’t smash into each other, allowing in this case to carry up to six bikes. It does all of this without frame contact, and offers three adjustments to fit different wheel bases and 24″ – 29+ wheels.”