prtyich

I will continue to update this review as I ride the bike for a longer period of time, but am starting today as this was the first extended ride (~15 miles) on the bike.

I had a 2008 Jack, which was a dream to ride, soaked up every pothole NYC could throw at it - it was like riding a Hummer, you just glided over the road. Those big apple 2-inchers were just amazing - but slow as molasses. I also wanted more than 7 gears, so I looked at an upgrade - and found it in the 2009/2010 Dahon Vitesse P18 (according to Dahon corporate, both years model is the same).

It has 20" kojak tires, which after almost 3 years of a 26" folder on an Abrams-tanklike frame, felt a bit wobbly at first, and you can certainly feel every pebble you ride over. BUT, they are quite nimble, and offer a degree of road control and maneuverability that a big wheeled bike could only dream of. Squeezing between cars waiting for the light to change is much easier now, and the V18 is just flat out faster than the Jack. I still will get passed by roadies pumping hard, but they will have to work harder to get by me, if I am pedaling with effort.

It looks like most of my time will be spend in gears 14-18, as the lower gears are too light unless going up a steep hill. The bike is a feather compared to the Jack, and requires less effort to move with velocity. As expected, the smaller wheel base does require more pedal rotations to move a set distance than the Jack.

It is a more fun bike to ride in general, and after an initial extended ride - the maiden voyage of the starship Vitesse - I can say so far I am pleased. I was going to upgrade the pedals and brake pads immediately, but looks like I'll only need to swap out the OEMs pads for Kool-stops as the pedals are serviceable.

I will try to update this review every few weeks as I become more acquainted with the bike, and experience additional positive/negative events. In some ways, I miss the simplicity of riding the Jack, where there was no need to ever look down at the road to view the condition of the road. But I think (hope) the tradeoff to a more sophisticated, capable and faster bike will be worth it in the long run.

snafu21

Neat. There is a nimble whippet-like pleasure in whisking through traffic on 20" spats. I've started overtaking (slow) lycra louts on my D7. Unbelieveable!

kamtsa

Kojacks are excellent tires (I use them) but may harsh on rough surfaces. You can soften the ride by adding a Thudbaster.

Also, you mentioned the reduced distance per pedal rotation (typically measured in Gear Inch units). You can look into using a larger chain ring. People with Dahon/P18 experience may provide more details.

tedi k wardhana

smaller wheel base doesn't have anything to do with pedal rotations.
maybe you meant: smaller wheel?
if you meant smaller wheel, then it still isn't relevant.
(I suggest you learn more about gear inch)

provided that a small wheel bike is equipped accordingly,
it can give the same distance with one pedal rotation, as a big wheel does.

(vitesse p18 is equipped with a 55t chainwheel. with the smallest cog 11t, it will give
100 gear inch. this will be the same as a road bike, the chain set at 53t, cog 14t...)

prtyich

The gear inches for the bike are from 31 - 96":

https://www.dahon.com/bikes/2010/vitesse-p18

prtyich

Week 3:

Bike continues to perform well, I've upgraded the pedals to Diamondback Bigfoots - a significant improvement over the stock foldables, and koolstop mountain salmon pads to improve braking performance.

Bike is very fast, I can keep up with most roadies with not much effort, only the gear ratio of 96" probably keeps me from going even faster and overtaking them. The speed can actually be a challenge sometimes, as there is much more wobble in a 20" bike than the 26" Jack I'm used to.

There is alot of play in the handle bar above the fork. The clamp is pretty tight, but there is still play in it, and I'm guessing it was designed so as to allow flex when riding over significant road hazards. Kind of like how a bridge or building is made to flex in the wind/earthquake, just something else to adjust to after the rock-solid Jack.

snafu21

"There is alot of play in the handle bar above the fork."

There shouldn't be any - if you mean the first joint above the steer tube headset bearings on the frame. If it's the headset it can be tightened up by loosening the horizontal allen head screw, and tightening up the large 10mm preload screw (vertical). then tightening the clamp screw. It has to be done in that order. Pick the front of the bike up with the handle bar and shake it back and forth along the wheel axis and bump the front wheel on the ground. Anything clicks or moves, it's wrong.