There is no standard stem tube diameter. It varies from bike to bike.
Pete P.
"GrandmasterE" <hardcore...@hotmail.com> wrote in message
news:ce52cb6.03012...@posting.google.com...
Often enough it will be 20-25 mm at top and 25-30 mm at bottom. Important
things to KIM: Bigger tubes are way stiffer and bigger bearings have way
more load capacity; fit is important (stems should be press-fitted into
bearings at bottoms and a good light drive fit at tops; wall thicknes is
as important if not moreso than dia, with good enough being about 4-5 mm
under thread roots at top and 6-7 mm at bottom, finally, aluminum stems
are usually wayyyy too limber for good handling.
Regards,
Hoyt McKagen
Belfab CNC - http://www.freeyellow.com/members/belfab/belfab.html
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My dog drove off in my pickup truck, but left my wife behind!!