My knowledge of grammar isn&#x27;t great, but isn&#x27;t bike(-ride) working as a noun here? I can use it as a verb and say &quot;I biked here this morning&quot; or &quot;it&#x27;s faster if you bike across the bridge&quot;. But I&#x27;ve never heard &quot;I&#x27;m going for a bike&quot;, or going for a &quot;20 mile bike&quot;. Bike ride is what sounds natural in those sentences.<p>And yet you can &quot;go for a run&#x2F;jog&#x2F;walk&#x2F;swim&quot;. English is weird. I guess it&#x27;s because bike as a noun already means the bicycle itself, while there is no object named &quot;run&#x2F;jog&#x2F;swim&quot;.