You can find walkable, safe neighborhoods all across the city, so it will likely come down to the location of your work, and the type of lifestyle you prefer (laid back, in the scene, family life, etc.). I live on the west side myself, so I'll speak to this area.
What is a Concave Wheel? Concave Technology takes the center of the wheel and dips inwards to give it that bowl effect. Rather than exaggerating a bigger lip for the back wheel, and a smaller lip for the front. Concave wheels emphasize the concavity of the rear wheel to differentiate from the front wheel.
A cogwheel is a mechanical part used in machine assemblies. It is also known as a gear and is an essential part of many common devices, including automotive transmissions. The body of the gear rotates just as a wheel does, and its outer edge is lined with protuberances called teeth or cogs; hence the name cogwheel.