have a cube attempt frame ,but how do i know which stem size to go for 100 110 120 ?,iam 5 9" the frame size is a 53cm ,thanks.
If you're getting it from a shop then get them to advise - ideally by trying out different combos. Otherwise have a look here when I asked a similar question http://road.cc/content/forum/26235-does-size-matter
first thing is that it makes a big difference. I not long got a secondhand bike and although the frame was the right size I constantly felt that I was stretching for the bars - I crudely measured the handlebar at about an inch and a half further away than I'd like. Turns out it had a stem of 11cm.
I basically got a cheap noname 7cm stem (so pretty much at the other extreme) mail order, and just swapped them over. Really, I bought it just to experiment and it was sufficiently cheap that I could just chuck it away.
But it was good to have for comparison and as soon as some money becomes available I might buy a better stem (carbon even?) at about 8cm, which should be ideal.
I agree with Hatter - if you can get your LBS to indulge you, they're bound to have different stem lengths in stock for you to experiment.