my schwinn is a 1990 bmx frame it was like 300$ but i paid 50$ i need to know what crank to get like a primo power bite or something good iam looking for a crank with speed

Profiles

cranks won't necessarily give you speed but if you're looking for a great crank for racing you can't go wrong with a set of Profiles, and if you're of average heigth 180mm is better for power and 175mm is going to allow you to spin a little bit quicker but won't give you the power the 180mm would.

profiles

I would totally go with Profile race cranks.. they are like 120 and have a lifetime warrenty on breaking and bending.. good thing.. I snapped my crank arm a month ago and they switched it, no problem. Totally profile.

profiles lol

They are just about top stuff so go for it if you can aford it. If not look for a nice heat treated crank. Warrenties are good to have, it means they have a good amount of trust in their product.