stock vs. custom frames

In article <[email hidden]>,

(Qui si parla Campagnolo ) said:

dianne-<< If the tubing has the same OD (likely), and if the 853 tubes have
thinner walls (very likely), then the 853 frame will be slightly more
flexible. >><BR><BR>

Not a metalurgist or a frame builder but 'stiffness' depends on outside
diameter, not wall thickness.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

My bike frame uses round tubes, I think the new 853 tubes are ovalized a
bit, supposedly to increase stiffness. I suppose that would make a
difference.

"Matt O'Toole" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Qui si parla Campagnolo said:

mark-<< My frame is Reynolds 525. Any idea how different a

853 frame

Quoted message said:

Quoted message said:

would be,

if at all? >><BR><BR>

If well made, just lighter. All the creaking and groaning is

not the

Quoted message said:

Quoted message said:

frameset 'flexing'.

mark-<< I thought the reason sales people were pushing

carbon forks

Quoted message said:

Quoted message said:

so hard was the claim that they ride so much smoother and

dampen road

Quoted message said:

Quoted message said:

shock. >><BR><BR>

Mostly marketing. A well made steel fork will work well also.

This is true. Plus, it's easier to tell if it's damaged,

should you ever crash.

Quoted message said:

A carbon fork could be fatally damaged without showing it.

<snip>

I like carbon forks because they are about a half-pound lighter
than my steel forks and they feel just as stiff. No magical
smoothing effect, though. And so far, after 10 years, no failure
problems. -- Jay Beattie.

On 07 Jun 2004 13:05:20 GMT, [email hidden] (Qui si parla

Campagnolo ) said:

dianne-<< If the tubing has the same OD (likely), and if the 853 tubes have
thinner walls (very likely), then the 853 frame will be slightly more
flexible. >><BR><BR>

Not a metalurgist or a frame builder but 'stiffness' depends on outside
diameter, not wall thickness.

For round tubes as used in bike frames,
differences in outside diameter have the greatest effect on stiffness,
but if the OD is the same, then wall thickness directly affects tube
stiffness.

(All else equal, i.e. butt length, etc.)

Qui si parla Campagnolo said:

dianne-<< If the tubing has the same OD (likely), and if the 853 tubes have
thinner walls (very likely), then the 853 frame will be slightly more
flexible. >><BR><BR>

Not a metalurgist or a frame builder but 'stiffness' depends on outside
diameter, not wall thickness.

The Area Moment of Inertia (I) for a hollow tube of outer diameter "d"
and inner diameter "di" about its symmetrical axis is:

I = pi/64*(d^4 - di^4).

Since "d" is the outer diameter of the tube and "di" is the outer
diameter minus the wall thickness, we can see that wall thickness does
indeed influence the stiffness of the tube.

--
Tom Sherman – Quad City Area

On Mon, 07 Jun 2004 12:41:31 -0400, Mark Heiple <[email hidden]>

Quoted message said:

In article <[email hidden]>,

(Qui si parla Campagnolo ) said:

dianne-<< If the tubing has the same OD (likely), and if the 853 tubes have
thinner walls (very likely), then the 853 frame will be slightly more
flexible. >><BR><BR>

Not a metalurgist or a frame builder but 'stiffness' depends on outside
diameter, not wall thickness.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

My bike frame uses round tubes, I think the new 853 tubes are ovalized a
bit, supposedly to increase stiffness. I suppose that would make a
difference.

OD, wall thinkness, material, shape and length all factor into the
stiffness of any member. At Cybex we designed the new treadmills with
oval tubes and had to carefully select the wall thickness so they
would be stiff enough at the outer diameter we wanted for the
stantions. The oval shape contributed to strength, but in one plane
only.

Michael J. Klein [email hidden]
Dasi Jen, Taoyuan Hsien, Taiwan, ROC
Please replace mousepotato with asiancastings
---------------------------------------------

On Mon, 7 Jun 2004 10:31:53 -0400, "Matt O'Toole" <[email hidden]>

Quoted message said:

Again, I bet this is the cheap way to make a bike these days, w/ carbon rear
ends being stamped out like Oreos.

They're not exact stamped out per se.

http://www.asiancastings.com/recumbent.htm

I saw Chuan Well making carbon fiber frames (see the 2nd installment).
Michael J. Klein [email hidden]
Dasi Jen, Taoyuan Hsien, Taiwan, ROC
Please replace mousepotato with asiancastings
---------------------------------------------

I'd suggest finding a stock bike that fits and riding it awhile before
going custom. Unless you have a really odd body shape, as a man, you
can find a dozen or two dozen stock bikes to fit you. I think you
really need to know your correct bike size before exploring custom
frames, unless you really have an odd body shape. Just because a
frame builder knows a lot about welding, brazing, metal work, etc. is
no guarantee they know anything about fitting people to bicycles. You
need a well fitting bike to know if the numbers a custom builder gives
you sound reasonable. Kind of a Catch-22.

AT 6'2" you probably fit a 60-62 cm frame. Give or take a little bit.
Go find some at the various bike shops in your town and take them for
extended rides. 20 miles or so. Think about how they fit compared to
your current bike. After 4 years of riding you do know something
about how a bike fits you. At least what does not fit. Use this
information when selecting a new bike. Try to get the bikes well
setup before the test ride. Seat height, seat setback, handlebar
height, stem length, your pedals fitted.

Aluminum, steel, carbon, titanium, etc. does not matter for sizing
purposes. You are still figuring out frame size. Once you find a
bike or two that seems to fit you best, then you can use the numbers
from these frames to determine which other bikes should fit you. Then
you can decide what material your bike will be made of.

Mark Heiple <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

I've been riding a 2000 Lemond Tourmalet (Reynolds 525 frame, 57cm) now
for about 4 years and been thinking of upgrading.

To make a long story short, when I first got the bike, I was ignorant
about how it was supposed to fit. I went to the wrong bike shop, who was
more interested selling bikes then making sure I got what I needed. I'm
convinced now that my frame is too small, so now I'm looking around for
new one. I've tried installing longer seat posts and stems, but I don't
think it is quite right.

I think my first step is to find a bike shop with a fit kit, take my
bike with me, and figure out if it really is a problem.

If it isn't right, my first choice would be to look at another lemond.
I really like the way the lemond handles, but their bikes have changed.
The new frames are steel/carbon or ti/carbon, and I hesitant to trust a
version 1.0 design. Anyone know how they are holding up?

I also noticed their geometry isn't the same - the chainstays (and
therefor wheelbase) are shorter. How much would this affect the
handling? I've tried short, compact frames before (Giant) and didn't
like it - very squirrely. Do the short stays restrict my tire size
choice? Right now I'm running GP 3000, 25c.

Lemond still has the old steel frames available as custom bikes, but
it's so expensive it's worth considering going custom (Waterford,
Serotta, etc) instead.

I know I need to go out and start test riding bikes again, but how does
one test ride a custom bike when there aren't any in your area and a
frame built to your measurements doesn't exist? Seems like an expensive
gamble to build a bike that you have never ridden.

I'm a lot more comfortable riding now compared to 4 years ago, so maybe
I don't need the extra stability of the lemond any more.

I'm 6'2", 225 lbs. I think have long legs & arms, short torso for
people my size. I don't race and never will. I have my handlebars set
about 1.5" below my saddle. I don't really need nor want an ultra-light
weight weenie bike. With all he stuff I carry in my saddle bag, my
tourmalet weighs about 26 lbs.

Since my old bike is steel and I really like the ride, I'm a bit
prejudiced toward steel, but I know that as long as the bike fits,
material isn't supposed to matter. I've been on some fat-tubed aluminum
bikes that were really harsh though. I've never been tried a Ti or
carbon bike, so I guess I should.

Thanks.

Tim McNamara wrote:
-snip chainstays-

Quoted message said:

I've never understood the attraction for short chainstays. The bike
handles badly in turns, the rear tire wears out more quickly, the ride
is less comfortable, chainline problems are worse, and there's no
benefit whatsoever. A peculiar trend altogether.

Agreed. My vote for one of those outlying data points is the
mid-seventies ultra short Schwinn tandem with curved seat
tube. With the front changer at 12:00 there is no triple
changer that will work at all in my experience.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971