Wheels

I had always assumed that lighter wheels were faster but I have been
reading recently that wheel weight, in the amounts usually encountered
in bicycle wheels is largely superficial and the aerodynamic factor is
far more important, thus the common "carbon wheel" is normally heavier
but being more aerodynamic is faster.

Since the wind resistance does increase by the square with doubled
road speed this does seem reasonable, but sometimes what seems true
isn't what things actually feel like in actual use.

Has anyone gone from light weight aluminum alloy rims to carbon rims
which are more aerodynamic but heavier? And if so what has your
experience been.

I suspect that on a, say 10 mile time trial, the carbon rims might
prove beneficial but how about on a, say 50 mile "Sunday ride"?
--
cheers,

John B.

a few grams on the front is feelable ....centripetal force known or felt as gyroscopic...loose engineering but that's the feel.

carbon wheel$ wear out

internet is prob replete with mudslinging n various forms of engineering data that I will not look for.......

"John B." wrote in message ...

I had always assumed that lighter wheels were faster but I have been
reading recently that wheel weight, in the amounts usually encountered
in bicycle wheels is largely superficial and the aerodynamic factor is
far more important, thus the common "carbon wheel" is normally heavier
but being more aerodynamic is faster.

Since the wind resistance does increase by the square with doubled
road speed this does seem reasonable, but sometimes what seems true
isn't what things actually feel like in actual use.

Has anyone gone from light weight aluminum alloy rims to carbon rims
which are more aerodynamic but heavier? And if so what has your
experience been.

I suspect that on a, say 10 mile time trial, the carbon rims might
prove beneficial but how about on a, say 50 mile "Sunday ride"?
--
cheers,

John B.

As you say the time diffeence on a TT is measurable but on a Sunday ride then it really depends on the wheels whether I can tell the difference. I have standardised on Shimano wheels for TT, summer events, and summer training and those are Dura Ace C50, Dura Ace C24 and RS80 C24. The C50s are measurably faster than the C24s for TT. Also for TT I put disc covers on the rear C50 which increases the weight but the bike is again measurably faster due to the further improved aero.

The DA C50s weigh 1670gms, DA C24 1380gms and RS80 1530gms.

I will choose the DA C50s for relatively flat spoertives and the DA C24s for tackling events in the Alps, Pyrenees or Dolomites. Based on my TT experience I "believe" (no comparative data) that the lighter wheels benefit me on the long relatively steep climbs and as I will be needing to brake on the descents aero is a lot less important whereas where there is the opportunity for some long relatively flat fast cruising I go for the DA C50s to take advantage of the better aero.

That said I would not claim to be able to tell the difference between these wheels on the summer bike on a 50 mile "Sunday ride" when they all have the same tyre and tube combinations on.

I can however tell the difference going the other way. If I have my winter training wheels on which are Open Pro rims on Ultegra hubs. These weigh in at 1880gms. The bike definitely feels more sluggish. In this case the wheels are both heavier and less aerodynamic than any of the Shimano sets. On of the big differences is the spoke count and type. The Open Pros are 32/32 standard whereas all the Shimanos are 16/20 bladed. This affects both the weight and the aero.

Graham.

---
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Spiff !

graham, switched from round to aero spokeson same rim/tire/bike ? Results ?

Subjective results carbon-metal 50 miles patchy road surface ?

On 10/9/2016 8:21 PM, John B. wrote:

I had always assumed that lighter wheels were faster but I have been
reading recently that wheel weight, in the amounts usually encountered
in bicycle wheels is largely superficial and the aerodynamic factor is
far more important, thus the common "carbon wheel" is normally heavier
but being more aerodynamic is faster.

Since the wind resistance does increase by the square with doubled
road speed this does seem reasonable, but sometimes what seems true
isn't what things actually feel like in actual use.

Has anyone gone from light weight aluminum alloy rims to carbon rims
which are more aerodynamic but heavier? And if so what has your
experience been.

I suspect that on a, say 10 mile time trial, the carbon rims might
prove beneficial but how about on a, say 50 mile "Sunday ride"?

I've never used carbon wheels, but I did something similar once, long
ago. As a birthday gift, I was given a set of spoke covering wheel
discs. They were nylon fabric stretched over an aluminum hoop, with
clips that fastened them to the spokes.

I was pretty enthused because I'd attended a Human Powered Vehicle (AKA
streamlined bike) workshop where the presenters demonstrated the aero
benefit. Spokes really do churn the air a lot!

Anyway, I installed those on the rear wheel of my (then) only bike, the
one I used for commuting, touring, time trials, etc. In those days, most
of my rides home from work were treated as time trials. I recorded the
times and killed myself trying to go fast.

Suffice to say I could never detect a difference in those times, nor in
the way the bike felt.

This doesn't mean the discs didn't help. Indeed, I did install them for
a while when I did a time trial or a century ride, because I was sure
they made _some_ difference. But the difference certainly didn't change
the riding experience. Ultimately, I just stopped using them.


--
- Frank Krygowski

On Sunday, October 9, 2016 at 5:21:54 PM UTC-7, John B. wrote:
I had always assumed that lighter wheels were faster but I have been
reading recently that wheel weight, in the amounts usually encountered
in bicycle wheels is largely superficial and the aerodynamic factor is
far more important, thus the common "carbon wheel" is normally heavier
but being more aerodynamic is faster.

Since the wind resistance does increase by the square with doubled
road speed this does seem reasonable, but sometimes what seems true
isn't what things actually feel like in actual use.

Has anyone gone from light weight aluminum alloy rims to carbon rims
which are more aerodynamic but heavier? And if so what has your
experience been.

I suspect that on a, say 10 mile time trial, the carbon rims might
prove beneficial but how about on a, say 50 mile "Sunday ride"?
--
cheers,

John B.

How is it that carbon rims are more aerodynamic?

Doug Landau wrote:
On Sunday, October 9, 2016 at 5:21:54 PM UTC-7, John B. wrote:
I had always assumed that lighter wheels were faster but I have been
reading recently that wheel weight, in the amounts usually encountered
in bicycle wheels is largely superficial and the aerodynamic factor is
far more important, thus the common "carbon wheel" is normally heavier
but being more aerodynamic is faster.

Since the wind resistance does increase by the square with doubled
road speed this does seem reasonable, but sometimes what seems true
isn't what things actually feel like in actual use.

Has anyone gone from light weight aluminum alloy rims to carbon rims
which are more aerodynamic but heavier? And if so what has your
experience been.

I suspect that on a, say 10 mile time trial, the carbon rims might
prove beneficial but how about on a, say 50 mile "Sunday ride"?
--
cheers,

John B.

How is it that carbon rims are more aerodynamic?



They are not by default but you can get a more aerodynamic rim with less
weight penalty. That is the whole deal.

--
Lou

"Graham" wrote in message
...

"John B." wrote in message
...

I had always assumed that lighter wheels were faster but I have been
reading recently that wheel weight, in the amounts usually encountered
in bicycle wheels is largely superficial and the aerodynamic factor is
far more important, thus the common "carbon wheel" is normally heavier
but being more aerodynamic is faster.

Since the wind resistance does increase by the square with doubled
road speed this does seem reasonable, but sometimes what seems true
isn't what things actually feel like in actual use.

Has anyone gone from light weight aluminum alloy rims to carbon rims
which are more aerodynamic but heavier? And if so what has your
experience been.

I suspect that on a, say 10 mile time trial, the carbon rims might
prove beneficial but how about on a, say 50 mile "Sunday ride"?
--
cheers,

John B.

As you say the time diffeence on a TT is measurable but on a Sunday ride
then it really depends on the wheels whether I can tell the difference. I
have standardised on Shimano wheels for TT, summer events, and summer
training and those are Dura Ace C50, Dura Ace C24 and RS80 C24. The C50s
are measurably faster than the C24s for TT. Also for TT I put disc covers
on the rear C50 which increases the weight but the bike is again
measurably faster due to the further improved aero.

Unless you're going all out to save weight on anything you can, the only
significance of wheel weight is; "unsprung weight" if you have suspension.
And probably then, only if you have proper damping such as you'd find on an
engined vehicle.

On 10/10/16 11:21, John B. wrote:

I had always assumed that lighter wheels were faster but I have been
reading recently that wheel weight, in the amounts usually encountered
in bicycle wheels is largely superficial and the aerodynamic factor is
far more important, thus the common "carbon wheel" is normally heavier
but being more aerodynamic is faster.

Since the wind resistance does increase by the square with doubled
road speed this does seem reasonable, but sometimes what seems true
isn't what things actually feel like in actual use.

Has anyone gone from light weight aluminum alloy rims to carbon rims
which are more aerodynamic but heavier? And if so what has your
experience been.

I suspect that on a, say 10 mile time trial, the carbon rims might
prove beneficial but how about on a, say 50 mile "Sunday ride"?



A pair of Zipp 404 wheels are both light and aerodynamic.

Whether weight is an issue for you, is whether you have many hills and
how steep? In a race sprint, I'd want both aero and light.

--
JS

On 2016-10-10, Doug Landau wrote:

How is it that carbon rims are more aerodynamic?

For some years now, all the aerodynamic innovation has been
on carbon rim design, rather than alu rim. The carbon material
is also more amenable to producing the dimpled design that seems
to be more aero than a smooth surface.

http://www.zipp.com/technologies/aerodynamics/ablc.php

--
Gregory S. Sutter Mostly Harmless

http://zer0.org/~gsutter/