ive been considering getting one for a while but i wasnt sure id be able to ride one
Your inseam, seatpost tube height, saddle thickness, pedal thickness, and crank length determine whether you can ride a Coker, not your height.
about 6
My son Beau started riding a Coker when he was 4’ 11" (age 10). At that height, he could sort of use 152mm cranks, but not comfortably, so he started on 125mm cranks and did fine. Here are some photos from a few weeks before his 11th birthday: http://nhoover.smugmug.com/gallery/1076794.
This was on a stock Coker with the seat all the way down of course.
—Nathan
There is also the option of the customized Coker frame for short people.
I don’t know the minimum inseam length for that Coker, but it’s going to be about 4 inches less than the stock Coker.
I’m 165cm but with short legs 
It’s not possible to ride 150mm cranks comfortably with a big fat KH seat on a Std Coker frame. A cut down seat works fine though.
Short of your Alps picture, this has to be one of the best father/son uni pics of all time. Both riding the skinny road stripe…and wearing the same shoes apparently. Love the pedestrian checking you out.
Beau looks very young in that picture.
They both need to wear Hoover Yellow for a father/son shot 
I’ve got very short legs. For instance on my 24" onza with 150 cranks, I had to cut down the frame, not just the seat post.
I’ve just bought a coker with a cut down seat post made by Roger from UDC.uk and it’s great.
Cathy
It seems like i know…That kid from school 3 years ago. Was he VERY SMART so he had a laptop and like i thought his name was David… Hmmm but awesome pictures!
I wear 28-29" inseam jeans and ride a Coker. I did cut the frame and seat post down. You can cut about a inch off the neck of the standard frame. I use 170 and 150 cranks.