Rock the late 70's track racing style of Breaking Away's lead figure, Dave Stoller.
First, you need a properly outfitted red racing helmet. We found ours at a local Army Navy surplus store. Use paint or tape to dial in the detailing.
Next, you need the shirt. We just happen to have the Cutters shirt, made to spec, right down to Dave's racing number 34 on the back.
Then you'll need some black bike shorts. The shorter, the more authentic.
A little bit of blood on the shins really helps bring the whole costume together (and builds up your biker cred, to boot). You'll also want a bandaged wrapped around the right leg, below the knee.
And finally, a pair of ratty converse or similar classic trainers; the dirtier and more beat-up the better.