Why is BMX gearing so low I was watching the BMX racing on the 2012 Olympics and the gearing seems incredibly low. About half way down the start ramp they are already going too fast to keep pedalling and they barely seem to be able to pedal effectively any other time through the race.

Why don't they adjust the gearing to be higher so they can get more power down through the course?
The tracks do not have many long stretches and so cornering and getting ahead of the pack is a lot more important than going fast in the flats. The gearing on a race BMX is higher than on one you will buy out of the store. Most BMX will come with 44:16 gear ratio where racers will use 46-48:16, and I have seen higher. (There are different rear sizes but the standard is 16 when talking about Gear Ratios, even if you ride 9t or 14t rear you almost always know the conversion to 16t.)

Most racers will start with 44/45:16 then move up when they build their leg muscles to handle the higher ratios, but even then you really need that hole-shot a lot more than you need the higher end speed.

If the tracks had longer straights like a mountain bike course you might see more bikes with multiple gears and even higher gearing. As it stands, the berms are where you make your moves and getting in and out of the berms require more power than raw speed. I raced 44:16 against guys with 46:16 and never placed lower than 3rd. You want more power than over all speed on a race track.

On street or in park you want even lower gearing, especially when you are trying to get that last pop before jumping up onto a rail.