Sportive (aka 'endurance') bikes are closely related to road bikes - very light and fast, but with a greater emphasis on rider comfort
Geometry. As a rule, sportive bikes have a slightly more upright geometry than standard road bikes, which is achieved with a shorter top tube and longer head tube. This brings the handlebars higher and closer to the rider, meaning those all-day rides shouldn't be such a stress on your back. This does result in a small loss in aerodynamic efficiency, but the greater comfort over long distances can translate into higher performance.
Stiffness. The frame on a sportive bike is designed to provide more 'compliance' in places that can maximise the comfort of the rider. Specifically, these bikes can have longer chainstays or thinner seatstays, which both have the effect of 'flexing' more under load or shocks. This is to cut out the road vibration, as a frame that is too stiff will transmit the road buzz on to the rider, which will lead to greater rider fatigue over distance. Cannondale, in particular, are pioneers of these designs. Their hugely popular Synapse frames employ what they call "S.A.V.E" frame technology, where the frame tubing is shaped to give the best power transfer without discomfort for the rider.
Gearing. Nearly all modern road bikes use a compact double chainset but Sportive bikes use them exclusively. In combination with wide-range rear cassettes, the bike has the same gear range as a triple chainset but with simplier and lighter parts. It also means the rider has a gear for every occasion.
If you are a cyclist looking for a bike to complete all-day rides, speedily, but in comfort, or have a full season of sportive rides planned, then these are the bikes for you. Make no mistake, they are just as capable of the same turn of speed as road race bikes, but are more focussed towards comfortable endurance.
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