wheel aerodynamics and poor man's TT wheel

[Squat'n Dive]

Spokes on which wheel: front or back create more drag?
If you tape the spokes on a wheel or two does that increase
the crosswind effects dramatically, or not very much so, due
to the wheels being in motion?

 

[[email protected]]

On Jan 9, 8:31 pm, "Squat'n Dive" <[email protected]> wrote:
> Spokes on which wheel: front or back create more drag?
> If you tape the spokes on a wheel or two does that increase
> the crosswind effects dramatically, or not very much so, due
> to the wheels being in motion?

The front wheel creates more drag, but the only reasonable way to make
a spoked wheel more aero is a disc cover which should only be done on
the rear.

 

[Donald Gillies]

[email protected] writes:

>The front wheel creates more drag, but the only reasonable way to make
>a spoked wheel more aero is a disc cover which should only be done on
>the rear.

That is not what I have heard. I read on some website (sorry, forgot
where), that there was a measureable improvement (almost 1%) in drag
just by going from 36 to 32 spokes, whereas bladed spokes didn't help
much.

I suspect that most of the drag from a wheel is from the wheel turning
around, NOT from turbulance generated as still air passes over the
tire and wheel. If I am right, then de-spoking the front and rear
wheels is the primary cure for excess drag.

- Don Gillies
San Diego, CA

 

[Tom Sherman]

[email protected] wrote:
> On Jan 9, 8:31 pm, "Squat'n Dive" <[email protected]> wrote:
>> Spokes on which wheel: front or back create more drag?
>> If you tape the spokes on a wheel or two does that increase
>> the crosswind effects dramatically, or not very much so, due
>> to the wheels being in motion?
>
> The front wheel creates more drag, but the only reasonable way to make
> a spoked wheel more aero is a disc cover which should only be done on
> the rear.

Why not on the front? I have used a temporary wheel cover on the front
wheel with no problems.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people." A. Derleth

 

[Zog The Undeniable]

Tom Sherman wrote:

> Why not on the front? I have used a temporary wheel cover on the front
> wheel with no problems.
>
Steering in a crosswind is "interesting". Fine for indoor velodromes,
though.

 

[Tom Sherman]

Zog The Undeniable wrote:
> Tom Sherman wrote:
>
>> Why not on the front? I have used a temporary wheel cover on the front
>> wheel with no problems.
>>
> Steering in a crosswind is "interesting". Fine for indoor velodromes,
> though.
>
I never had those issues, even in windy conditions. One of the
advantages of the ISO 305-mm wheel size, I suspect.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

 

[buzz66]

Just guessing but any form off crosswind with a disk front wheel would
slow you down.

 

[Tom Sherman]

buzz66 wrote:
> Just guessing but any form off crosswind with a disk front wheel would
> slow you down.

Actually, the opposite is more likely to be true.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

 

[Mark]

Tom Sherman wrote:
> buzz66 wrote:
>> Just guessing but any form off crosswind with a disk front wheel would
>> slow you down.
>
> Actually, the opposite is more likely to be true.
>
When the crosswind plus front disk puts you in a ditch, that slows you
down.

The squirrely feeling may slow you down even without a bike-ditch
convergence, perhaps by the physics (straight line paths are faster) or
psychologically (distractions prevent making your best effort).

Mark J.

 

[Tom Sherman]

Mark J.? wrote:
> Tom Sherman wrote:
>> buzz66 wrote:
>>> Just guessing but any form off crosswind with a disk front wheel would
>>> slow you down.
>>
>> Actually, the opposite is more likely to be true.
>>
> When the crosswind plus front disk puts you in a ditch, that slows you
> down.
>
> The squirrely feeling may slow you down even without a bike-ditch
> convergence, perhaps by the physics (straight line paths are faster) or
> psychologically (distractions prevent making your best effort).
>
butbutbut, I never had the handling problems people go on about!

Maybe the secret is to use a front wheel that is only about 1 foot
square in side area?

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth

 

[still just me]

On Sun, 13 Jan 2008 12:32:25 -0600, Tom Sherman
<[email protected]> wrote:

>I never had those issues, even in windy conditions. One of the
>advantages of the ISO 305-mm wheel size, I suspect.

Yeah, but ur riding a Shriner's clown tricycle! They're known for
their stability.

 

[Tom Sherman]

still just me wrote:
> On Sun, 13 Jan 2008 12:32:25 -0600, Tom Sherman
> <[email protected]> wrote:
>
>> I never had those issues, even in windy conditions. One of the
>> advantages of the ISO 305-mm wheel size, I suspect.
>
> Yeah, but ur riding a Shriner's clown tricycle! They're known for
> their stability.
>
How can something with two wheels be a tricycle?

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth