Look at these timo888. These forks are on a Jetstream. I found them on-line to reply faster. The fork feels stiff until hitting a big bump or standing and pedaling. It is like riding on a tire with lower air pressure. I weigh 150 pounds and feel all the rocks and cracks but not fully. A heavier rider might have a smoother ride. It works because there is a rod attached to the fork going into the downtube that presses against an elastomer. The parallelogram braces hold it together. I've never seen the inside in person or in photos.

The Thudbuster is more compliant when hitting bumps. I like that it is adjustable for different rider weights or preferences. I would recommend putting either Thudbuster model on any unsuspended small wheel bicycle.

Unfortunately the Q-fork is not adjustable.

http://www.speedmatrixdepot.com:80/c...main/c_194.jpg

http://www.cyclemotion.co.uk/dahon/t-qfork.htm