ok I got a lot of great advice yesterday on a shifter, lets see how ya do on this, I have a giant mountain bike with a 23" frame which is nice when you're six foot six inches tall, what I'd like to do is change the handle bar stem to an adjustable one. looking on ebay I see several of them but there a lot of different sizes, my question is what size do I need? I plan on reusing the handle bars which I don't know? do I need a certain size for those as well? or just for the stem? you pulled me out of the fire yesterday can you help with this as well? thanks in advance, I love to ride but I am a novice at working on them.
Without pictures or an exact description of what you have (and with my crystal ball currently being polished...) we cannot really help you.
If you have a threaded headset you are lucky, getting a longer / different / adjustable stem is easy. For the more modern headsets: there are some adjustable stems, but I guess they might need a longer steerer tube on the fork, though this is hard to say without seeing what you are writing about.
I too need to add a longer stem to the steering head as I am too hunched over on my bike..it's tough on the shoulders and all. I wonder though, if making it taller puts undue stress on the neck and if so, is it worth the effort to change it out?
guys; as Joe says, if you do not provide enough information, we can not help you....
Also, after you've shown pictures, so we can see if you have a threaded or quill stem in 1" or 1 1/8", (which aren't actually 1" or 1 1/8"), or a threadless, I want to suggest changing the handlebars.
Your current MTB bars have the grips oriented for power & control.
Cruiser bars come up, out & back, for comfort, but at a price, as the grips are no longer perpendicular, but angled back.
Your current bars probably have a 2.5" rise. MTB high rise bars are very difficult to find with more than a 4.5 or 5" rise. I have found that about 7" is often what I need, but I can't find it. Some Electra bikes come with them, but I can't find them, only something close. (The ones on the Electra site aren't the same).
You angle the high rise bars up & back toward you for more comfort with power & control.
If you want a lot of handlebar options, your stem should be purchased for 1" (25.4mm) handlebars.
I think you need to clear up what you are really requesting. I am not sure if you are asking for a longer length of tubing on the headset or a longer stem that attaches to the fork. A stem attaches to the headset and orients the hands by its overall length. So you are asking for a longer stem, your hands are going to be moved further forward. But you state that you want to be taller??