Im using a 100mm reba on mine, i love the way it rides! i like the steering better than the hardtail i took it off of. I have not however ridden a Rip with a 120 or 140 mm fork other than a parking lot test ride, so i dont have much to compare it to. I will be upgrading when budget allows, but using what i already had allowed me to build and ride my Rip a whole lot sooner :thumbsup: