Hey,
My back of the envelope calc's indicate a standard aluminum quill stem will 
deflect about ten times more than a steel stem. This is with equal extensions 
lengths and loads, and the aluminum stem has a solid 22.2mm diameter extension, 
and the steel stem is 31.8mm OD w/ 25.4mm ID extension. The extension into the 
fork vs. clamping on the outside of the fork are not significant here.
By the way, neither stem deflects that much.
If you really want a stiff stem, use a short extension, and big diameter. And 
steel too.
And you know why they went to 31.8mm diameter handle bars? Because of the 
stinking cable grooves. The grooves make the bar section too flexible, the 
bigger diameter overcame this. 
Cheers!
James Valiensi, PE
Northridge, CA
H818.775.1847 M.818.585.1796



On May 6, 2011, at 6:44 PM, Philip Williamson wrote:

> When I got my Quickbeam, I tried a couple of stems, including the
> stock Technomic Deluxe and the Nitto Dirt Drop. Both flexed noticeably
> more than the Salsa welded stem I ended up with. The Dirt Drop not as
> much as the Technomic Deluxe, but the quill was bottomed out in the
> steerer.
> 
> Philip
> 
> 
> On May 6, 9:24 am, "Bill M." <bmenn...@comcast.net> wrote:
>> Back in 1991 I bought a Cannondale (very stiff frame) that came with a
>> standard quill stem.  I swapped it out for a hollow, welded stem that
>> had a much larger diameter extension.  The first time I stood up and
>> cranked the bike up a short steep rise I was astonished at how much
>> stiffer the front end of the bike felt.  The quill stem was allowing
>> the bars to twist, the new one wasn't.
>> 
>> That may or may not be seen as a good thing, but I have no doubt that
>> typical threadless stems are stiffer in torsion than traditional quill
>> stems.
>> 
>> Bill
>> 
>> On May 6, 3:58 am, MichaelH <mhech...@gmail.com> wrote:
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>>> The new RR contains an article by GP outlining his believes about
>>> various aspects of  bike strength, comfort, weight, and comfort.
>>> There wasn't much new there for anyone who has followed him for a few
>>> years, including why he prefers threaded headsets and stems, but it
>>> did trigger this question from me.
>> 
>>> My son, who is 39 years old and a very muscular 170 lbs claims that
>>> he experiences stem flex while climbing with a traditional quill
>>> stem.  I am always disinclined to challenge people's subjective
>>> experience but I have never experienced this and suspect it is in his
>>> imagination.
>> 
>>> Has anyone here felt their stem flex and has anyone ever broken a
>>> stem?
>> 
>>> michael
> 
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