Mr. Brown:
Couldn't help a further comment: the distance between bearings is about 1/2 of the total axle and
(rendering the compression between bearing surfaces 1/2 or less than the total distance between QR
ends). Also, if you take a look at axle on a Campy hub, it is thicker and of a much larger diameter
(hmmm, perhaps by a factor of 5 or probably more?). Did you take my challenge and empirically verify
your analysis of the question at hand?
You sound like the software engineers who I serve who say, "it can't have failed, my analysis shows
the software should behave as I designed it" as I show them the blue screen of death. Sometimes
paying attention in High School means little if you don't fully understand the parameters.
Your analysis misses the points I made above and probably more, therefore, even though I once
retracted my challenge, I SLAP YOUR FACE WITH MY FRILLY GLOVE ONCE AGAIN: PROVE IT! I want pix
of the micrometers. You work in a bike shop right? You can put non-QR axle bolts on with a
torque wrench, can't you? You have access to a micrometer or other high precision measuring
device, I assume?
Course, you could continue on in your merry, dismissive fashion. But then I will have the joy of
cobbling together some fake images proving my point, forcing you to either disprove through your own
efforts or to bear the derision of your peers - beaten by a mere cycling mortal on a technical
issue. And it will haunt you for the rest of your life ;-)
App "never trust anyone over thirty" Killer, who's over thirty and suspects Sheldon is too.
Sheldon Brown <[email hidden]> wrote in message
news:<[email hidden]>...
Quoted message said:The mysterious "Appkiller" predicted:
Quoted message said:I predict that the compression on the bearings represented by this reduction in distance due to
the compression by the QR on the Campy bearing distance is probably on the order of 1/10 to
1/20, or even smaller, than that of the Shimano hub.
The linear compression of the axle is proportional to the force from the QR, the average
cross-sectional area of the axle, and inversely proportional to the elastic modulus of the
material it is made from.
Thus, for a Campagnolo axle to compress only 1/10 as much as conventional axle as our anonymous
source predicts, it would have to have a cross-sectional area 10 times as great, and it would be
10 times as heavy...if it was made of steel.
Since the elastic modulus of aluminum is only 1/3 of that of steel, an aluminum axle would need
have a cross-sectional area 30 times that of a conventional axle.
However, since aluminum has only 1/3 the specific gravity of steel, it would still be only 10
times as heavy as the conventional axle.
I might have an unfair advantage here...I actually paid attention in my high school physics
class ;-)
Sheldon "QED" Brown +----------------------------------------------------------------+
| Anyone who cannot cope with mathematics is not fully human. | At best he is a tolerable
| subhuman who has learned to wear | shoes, bathe, and not make messes in the house. | --Robert
| A. Heinlein |
+----------------------------------------------------------------+ Harris Cyclery, West Newton,
Massachusetts Phone 617-244-9772 FAX 617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗ sheldonbrown.comsheldonbrown.comOpen ↗