Check your weight distribution over the bike. Folders typically provide a more upright position, with more of your weight distributed over the rear wheel (and your bum) and less over the front (hence many folder-riders' need for thudbuster seatposts, sprung/extra plush saddles). If you dial a little stretch into your bike with a longer stem, you can center your weight more evenly betwen the 2 wheels...

http://www.beginnertriathlete.com/cm...p?articleid=65