31.8 is the taipered diameter of my (well, my wife's) handlebars yes? they are specialized bars, and say 31.8 on them, but there is a taper down from where they enter the head tube.

Which thickness is defined by 31.8 is relevant because i am also getting her a new stem in addition to some bar top brakes.

thx

The 31.8 is the diameter of the bulge in the center.

Correct. The stem you buy must specify it's for 31.8 mm bars too since the stem's handlebar clamp will go around the bar at that center bulge.

From the center bulge, the bars will taper down to the standard 23.8 mm diameter where the brake levers or brifters are placed on road bars or 22.2 mm for where the brake and shift levers mount on MTB bars.

ok, thanks a ton!!! that makes a big difference as to which top lever brakes (cross brakes) i end up buying on ebay... i guess i do not want 31.8 (hope i get outbid) because i will probably wan to install them after the taper

those still would probably work, there's no many crosslever clamps that are actually 31.8mm.

I just want to see photos of "where they enter the head tube". :0

alright fool... you know what i meant... newbie just tryin to read and learn and wrench on his own junk here

adam - better develop a thicker skin here. 'bikinfool' was hardly insulting, just being himself. And welcome to Bikeforums! We're here to help others and ask questions. And there's a good crew of professional bike-mechanics here who can help you out. Have fun!

Happy Holidays from Norman Rockwell's Vermont.

Well, it was a funny visual at the moment...but using proper terms will get you better results than not otoh. Me knowing what you might mean isn't the same thing as you knowing what you mean...

well as my wife tells me, listen to what i mean, not what i say... haha

i was just bantering w/ him... I am a member on a few other forums, an offroad 4X4 site being one of them... i am not thin skinned at all haha