I get this (assuming diaphragm is aperture). Just to get this effect to work you have to stand very close to the bike, at which point the bike doesnt line up correctly. I think finding a location with a background far enough away will be key. Roads round here are always too busy to set the bike and tripod up in the middle of the road
With a fast lens you shouldn't have to stand too close. A 50mm will be fine, and with a telephoto, which is what Gaston means, the depth of field is narrower at the long end of the zoom range.
I'll give you a quick tutorial when you want a bike shot :)
I get this (assuming diaphragm is aperture). Just to get this effect to work you have to stand very close to the bike, at which point the bike doesnt line up correctly. I think finding a location with a background far enough away will be key. Roads round here are always too busy to set the bike and tripod up in the middle of the road