Using a 50mm f/1.8 for bmx photography?

Right Ive Agreed to take some shots of friends on bmx's at the local skate park and some good spots. Il be using my Canon EOS 400D but I only have the 18-55mm kit lens and the 50mm f/1.8.

Will this be of any good?

I think the 50mm's auto-focus will be too slow for action shots. Perhaps you can manually focus at a particular spot then get the shot as your friends pass. I have not used the kit lens so cannot comment on its abilities.

50mm? great lens but hmm id rather have longer to get closer shots of the bikers. I doubt youd wanna be too close if they do any jumps and stuff.
but, if they just riding on the street doing tricks, I could live with a 50mm.

the 50 will be ok...but you're probably best with a zoom.