i race on the MIT running track in the thursday night races that have been mentioned before, i usually do well. latley i have noticed that when i am in a full sprint pushing as hard as i can my fornt wheel pops off the ground. this has almost made me fall which is preety scary. any suggestions as to stop or avoid this form happening, i have a very short thredless stem (2 inches long) could that be the problem?

I'm guess your pulling too hard on your bars causing your front wheel to lift. Where you have your hand on the bars is also an issue, you want them just below the midpoint of the curve. You could also be too far back when sprinting or just not have sufficient control.

You need to practice sprinting so that your hands and weight are in the right place and you can turn on the speed with control. Trying running some whistle jumps/sprint intervals where you practice going from a slow pace to sprinting as fast as you can. Try some in the saddle and some out.

However, I'm not an expert and you may be better off asking this in the track specific sub-forum. Just my uninformed two cents.

When I go on group rides, we usually sprint to landmarks along the way. I can't win with only one gear, but I join in just for fun, and I have experienced this same thing before. When I started sprinting hard, the front wheel would just bounce all over the place--it's a little bit unnerving. It hasn't happened to me since I switched to bullhorns, so perhaps you should just lean forward more. In fact, I've actually lifted up my rear wheel from pulling up too hard.

adjust your weight forward. There's a balance their that you have to find. Also maybe rock the bike a little less too.

This happens becuase your chainstays are short. Calfee (www.calfeedesign.com) makes his bikes with real long chainstays. My front wheel never pops a wheelie, not even on step, slow climbs, or during sprints. I've always had that same problem before I switched to Calfee. Most people think long chainstays mean a sluggish bike, but I don't find that to be true, and my two podium finishes on a Calfee in my last two crits would tend to support my beliefs!

Anyway, since you probably don't want to change frames, the other suggestions above are good ones, but I just thought I rant a bit about frame geometry, because that is the root cause. Also getting a bit lower may help, bars with a deeper drop.

Also if you can pedal toes down and set your pedals up so that you are more on the front of your foot, that could also help.

If all else fails, you can try adding a link to your chain to move your axel back in the dropouts. Sometimes that extra 1/2" or so will give you the extra chainstay length to keep the front down.

maybe its because you're such a god damn animal at the sprints, let other people win sometimes! hahaha