Pumped BMX + Bandit : barspin icepick backflip challenge EASIEST WAY

Do not use race mode.
Do the barspin asap, when you are still coming off the jump.
Do the icepick grind low to lose less speed.
Start leaning back when you're approaching the end of the rail.
Clear every following jump in RACE MODE without doing any tricks (gives you more height)

I struggled with this too, untill I found the best, easiest way to do it.
Have fun :)