The two main modes of transport in Black Rock City are walking and riding a bicycle. If you've never attended before it is difficult to imagine how huge this temporary city actually is. Bring a bicycle!
This seems to be a matter of personal preference, but the vast majority of bikes on the Playa are cruiser style. Single speed, large seat, and upright posture when riding seems to be the most popular because of low cost, comfort, and easier maintenance in the dust. Another popular choice are mountain bikes. Try to avoid bringing expensive bikes. Avoid bicycles with narrow tires.
How Many Gears
Single speed bikes are great for their simplicity. Multi speed bike derailers tend to be more affected by the dust and may cause some issues. Those who do bring multi geared bikes generally pick one gear they like and don't shift it all week.
This is just repeated from my lighting page - Black Rock City is a pedestrian and bicycle city. If you are bringing a bike (highly recommended), you should at the very least have lighting for it at the front and back. Lighting the sides will improve your safety and is a good idea as well, but less essential. Headlights should be aimed to illuminate the ground in front - if you aim them too high you will blind oncoming traffic.
Sometimes it is handy to haul stuff on your bike (such as ice). At its simplest this means attaching a basket or rack. If you don't regularly ride with a loaded basket on the front of your bike, it is much better to mount a rack on the back of the bike. Loaded handlebar mounted baskets affect riding balance and stability much more than rear mounted. At its simplest, attaching a plastic crate to the bike with zip ties will work in a pinch.
Another popular option is a trailer designed for towing kids behind a bike.
For those who don't ride much, part of the playa experience is a really sore ass. I kid you not - you will see folks trying all sorts of futile methods to pad their seat. Get used to riding that bike long before using it on the playa. You will regret it if you don't in the form of aching muscles and a nasty case of playa ass (sore and / or blistered from a bike seat). I learned my lesson and now ride my bike to work a minimum of 3 times a week.
Bike theft (or as I like to call it - Radical self Gifting) is rampant on the playa. Sometimes it is just a case of mistaken identity, or someone who is in such an altered state they just grab the first bike they see. In the case of expensive bikes sometimes it is professional thieves preying on our trusting community. Regardless of the reason, use of even a cheap 3.00 locking cable will go a long way towards ensuring your bike remains where you leave it.
Whatever suits you except neon green / chartreuse. The public loaner bikes are this color so avoid hassles and bring any other color.
Decorating your bike so it looks unique will make it more fun to ride, less likely to be taken by mistake, and make it easier to find in a sea of bikes. Hint: Decorations that are tall or stick up higher than normal bike height may make it easier to locate when it's in the middle of a huge parking area such as those near the big sound camps.
Those flying in have two basic choices for a bike - buy a cheap one or rent one. Wally Mart has bikes in the $80 range as of this writing. There is also the option of renting a bike in Reno. Bike rentals are used to raise money for a good cause and usually announced in the Jack Rabbit Speaks Newsletter shortly before the event.
If you bought a bike, don't leave it on the playa as moop - there are organizations that will restore them and donate them to worthy causes. Again get the info from the Jack Rabbit Speaks Newsletter.