changing out the stem on a Trek 5200

I assume your model year Trek has a quill stem like this: http://www.google.com/imgres?um=1&hl=en&safe=off&client=firefox-a&sa=N&tbo=d&rls=org.mozilla:en-US:official&biw=1280&bih=643&tbm=isch&tbnid=jC-5gb6LDXeHUM:&imgrefurl=http://www.thefootdown.co.uk/2010/07/14/system-ex-track-bars-and-quill-stem/&docid=v5A6hAYdKYurgM&imgurl=http://thefootdown.co.uk/images/shopping/system-ex/2010-07-14-system-ex-quill-stem.jpg&w=391&h=500&ei=D4KxUPyADomtigLX64GQCA&zoom=1&iact=hc&vpx=291&vpy=234&dur=4181&hovh=254&hovw=198&tx=75&ty=199&sig=100614152627555017358&page=1&tbnh=145&tbnw=113&start=0&ndsp=22&ved=1t:429,r:9,s:0,i:142

If so, you can either stay with a quill stem of the appropriate length or you can use an adapter like this: http://www.excelsports.com/main.asp?page=8&description=Quill+Conversion+Adapter&vendorCode=PROFILE&major=1&minor=22 along with the theadless style stem of the length and rise/drop angle you want. You'll need to buy the quill adapter in the correct size for your bike which is either 1" or 1 1/8" so check the existing quill stem size.

But yes, you can upgrade to a modular stem if you'd like. The process isn't a ton of fun as you'll have to unwrap at least half of the tape from your handlebars and remove one brake/shifter lever to slide the bars out from the quill stem clamp and then put it back together again and retape the bars. At least most newer threadless stems have removeable faceplates so future changes are much easier.

-Dave

thanks Dave this will be a big help