5ft??? have fun replacing parts on both your bike and car. thats big, maybe too big for a rc car. just dont make it too steep or you will be bending chassis when you come down out of a 20ft air. i have a old ramp i made for biking along time ago, its about 2 to 2and1/2ft tall. id always jump my t3(electric stadium truck) out of it and easily get 6 feet high. so one day me and my brother put stuff under the end of it to make it steeper. i was getting at least 10 feet of air and rolling away. i think i did eventually brake something, but i got about 10 good jumps. we got alot of good footage of the ramp. once i set up a landing ramp about 25 feet away from the first ramp, i landed perfectly into the other side, it was great. but then i missed and hit the front of the landing ramp. it only broke the body but looked awsome. it stoped instantly lol. my brother jumped over a road with the ramp once to. i tried it and slammed into the curb on the other side upside down. but anyways, ive been thinking about making a track too, if my dad ever lets me.