Track Cycling: Velodrome Racing and Training Area - track build gear ratio

Building a purpose built track bike. but i dont know what gear ratio to run. im 17, and have good leg strength. i run 48 sometimes 52 on my road bike (crank). i was thinking like a 48x15?

Do you plan on racing on the track or just riding for fitness? Racers usually have two basic gears, one for warming up and one for competing. Normally the warm-up gear is something in the range 78" to 82", which might be 47x16. A typical race gear is in the range 88" to 92", which might be 47x14. So you could use a flip-flop hub with the 16T cog on one side and the 14T cog on the other. Later on you could add 46T and 48T chainrings to fine-tune your race gearing. The 48x15 you were proposing works out to 86", which is a little on the low side for racing and somewhat high for warming up. However, if you just plan on doing non-competitive workouts on a track, then just about any gear that lets you maintain a 100+ rpm cadence will do the trick.

I would say that 48x15 (86.4) is a good gear to start on for a 17 year old just starting out on the track.
That gear is actually the limit for racing age 15-16 here in the U.S. In the junior program at our track we use one tooth bigger chainring (above max allowed gear or race gear) to work on leg strength and power. So for our 15-16s they use 49x15 for those workouts. We go smaller for leg speed/spin workouts.
Racing is definitely not limited to one gear. The type of race, the distance, the weather, the track that you are at, even whom you are racing can factor into your gear selection for a race.
My kid is a 15-16, been racing since the age of ten. Has 45, 46, 47, 48 and 49 rings and 15, 16, and 18 cogs. My point is that you will start somewhere and add as needed.

Some might say that a 48x15 is too small. What you need to know is that the same gear you like on a road bike is harder on the track for most people. You also need to develop a really good spin and pedaling form, because when the speed builds, you can't change to a bigger gear. Your legs have to be able to keep up. Better to start out in a gear that is a little small than one that is a little too big.

Like Velodad said, 48 or 49x 15 is a good place to start, but if you start racing very much you'll end up with a bag full of chainrings that add up to as much as your frame cost.

go to your local track, ride the rentals a bit, see what other people are riding/racing in the fields you'll be racing in, and start from there.

im going strictly track, im getting ready to races, in a velo in queens ny.

Kissena - You'll find a lot of knowledgeable people there.