spray wake..?

[Larry English]

say you are riding on a fairly wet road.

there aren;t puddles but the road is shiny and basically wet.

you have no fenders.

standard road bike tires and wheels.

stay below about 9-10 mph and you have a dry back.

how fast do you have to go before the spray from the back wheel can;t make it up to your back?

wle.

 

[Asqui]

larry english wrote:
> say you are riding on a fairly wet road.
>
> there aren;t puddles but the road is shiny and basically wet.
>
> you have no fenders.
>
> standard road bike tires and wheels.
>
> stay below about 9-10 mph and you have a dry back.
>
> how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>
> wle.

I think once you reach the threshold speed for back-spray you're going to get more and more sprayed
the faster you go. You'd have to go pretty damn fast to have all the water leave the wheel before it
spins half a turn.

 

[Ron Hardin]

larry english wrote:
> how fast do you have to go before the spray from the back wheel can;t make it up to your back?

The spray is going twice as fast as you are
--
Ron Hardin [email protected]

On the internet, nobody knows you're a jerk.

 

[Asqui]

Ron Hardin wrote:
> larry english wrote:
>> how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>
> The spray is going twice as fast as you are

How do you figure that? I make it that the linear velocity of your tyre circumference is equal to
"your" velocity.

Dani

 

[Stu]

but the tyre has to get back round the front again. where the tyre hits the road it isn't moving at
all. its all about where you are when you measure the speed. if the bike is doing 30mph. if you look
at it from the side of the road, then the tyre on the road isn't moving at all and the tyre at the
top of the wheel is doing 60mph if you look at it from on the bike, then the tyre on the road is
going backward at 30mph and the tyre at the top of the wheel is going forward at 30mph

 

[Paul Southworth]

In article <[email protected]>, larry english <[email protected]> wrote:
>say you are riding on a fairly wet road.
>
>there aren;t puddles but the road is shiny and basically wet.
>
>you have no fenders.
>
>standard road bike tires and wheels.
>
>stay below about 9-10 mph and you have a dry back.
>
>how fast do you have to go before the spray from the back wheel can;t make it up to your back?

A lot faster than you can safely ride on a wet road.

 

[Jim Adney]

On Tue, 22 Jul 2003 22:56:04 +0000 (UTC) "asqui" <[email protected]> wrote:

>Ron Hardin wrote:
>> larry english wrote:
>>> how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>>
>> The spray is going twice as fast as you are
>
>How do you figure that? I make it that the linear velocity of your tyre circumference is equal to
>"your" velocity.

Consider that the speed of the part of the tire that is actually in contact with the ground is
actually zero. Similarly, the speed at the top of the tire is twice the bikes speed. [If the speed
at the top was exactly the bike's speed, it would never be able to move forward and get back to the
ground....]

-
-----------------------------------------------
Jim Adney [email protected] Madison, WI 53711 USA
-----------------------------------------------

 

[Squid-In-Traini]

"asqui" <[email protected]> wrote in message news:[email protected]...
> Ron Hardin wrote:
> > larry english wrote:
> >> how fast do you have to go before the spray from the back wheel can;t make it up to your back?
> >
> > The spray is going twice as fast as you are
>
> How do you figure that? I make it that the linear velocity of your tyre circumference is equal to
> "your" velocity.

Velocity relative to a stationary observer. Poster was describing linear v at 12 o clock.

--
Phil, Squid-in-Training

 

[Larry English]

> >
> >how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>
> A lot faster than you can safely ride on a wet road.

ha ha.

what i was really thinking of was, air resistance.

sure the spray travels twice as fast at the top of the wheel, etc.

but at some point, you get away from it, because it slows down from air resistance, as you
speed away.

i guess i could try it and see..

kind of hard to observe though.

wle.

 

[Asqui]

larry english wrote:
>>> how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>>
>> A lot faster than you can safely ride on a wet road.
>
> ha ha.
>
> what i was really thinking of was, air resistance.
>
> sure the spray travels twice as fast at the top of the wheel, etc.
>
> but at some point, you get away from it, because it slows down from air resistance, as you
> speed away.
[...]

Not really: it would be right behind you in your slipstream. (This means you'd have to go even
faster to achieve the desired effect.)

Dani

 

[Patrick Lamb]

asqui wrote:
> larry english wrote:
>
>>>>how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>>>
>>>A lot faster than you can safely ride on a wet road.
>>
>>ha ha.
>>
>>what i was really thinking of was, air resistance.
>>
>>sure the spray travels twice as fast at the top of the wheel, etc.
>>
>>but at some point, you get away from it, because it slows down from air resistance, as you
>>speed away.
>
> [...]
>
> Not really: it would be right behind you in your slipstream. (This means you'd have to go even
> faster to achieve the desired effect.)

I think the answer to the original question is pretty close to 0 mph (conversion to metric left as
an exercise to the reader!). I find I can go rather slowly and the water doesn't come off the tire,
but at any significant speed, I'm gonna get wet.

Pat
--
Apologies to those easily confused. Address is spam-resistant. Correct email address like pdlamb
'round-about comcast point net.

 

[Werehatrack]

On 23 Jul 2003 12:36:43 -0700, [email protected] (larry english) may have said:

>> >
>> >how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>>
>> A lot faster than you can safely ride on a wet road.
>
>ha ha.
>
>what i was really thinking of was, air resistance.
>
>sure the spray travels twice as fast at the top of the wheel, etc.
>
>but at some point, you get away from it, because it slows down from air resistance, as you
>speed away.
>
>i guess i could try it and see..
>
>kind of hard to observe though.

From my open-wheel car racing days, the answer is about 85, maybe 90, if there's nothing breaking
the wind above and in front of the tire...which is where *you* would be, doing just that. Ergo, the
wind will not save you.

--
My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
don't respond to something, it's also possible that I'm busy.

 

[F1]

Even if there is some speed at which that can happen, someone mentioned that it wouldn't be a speed
you'd want to go on wet road, but since your question about about a dry back, wouldn't you be pretty
wet up front?

"larry english" <[email protected]> wrote in message
news:[email protected]...
> say you are riding on a fairly wet road.
>
> there aren;t puddles but the road is shiny and basically wet.
>
> you have no fenders.
>
> standard road bike tires and wheels.
>
> stay below about 9-10 mph and you have a dry back.
>
> how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>
> wle.

 

[Werehatrack]

On Sat, 26 Jul 2003 15:37:05 -0500, Patrick Lamb <[email protected]> may have said:

>asqui wrote:
>> larry english wrote:
>>
>>>>>how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>>>>
>>>>A lot faster than you can safely ride on a wet road.
>>>
>>>ha ha.
>>>
>>>what i was really thinking of was, air resistance.
>>>
>>>sure the spray travels twice as fast at the top of the wheel, etc.
>>>
>>>but at some point, you get away from it, because it slows down from air resistance, as you
>>>speed away.
>>
>> [...]
>>
>> Not really: it would be right behind you in your slipstream. (This means you'd have to go even
>> faster to achieve the desired effect.)
>
>I think the answer to the original question is pretty close to 0 mph (conversion to metric left as
>an exercise to the reader!). I find I can go rather slowly and the water doesn't come off the tire,
>but at any significant speed, I'm gonna get wet.

And it didn't take a government-funded research project to find out, either.

--
My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
don't respond to something, it's also possible that I'm busy.

 

[Patrick Lamb]

On Sat, 26 Jul 2003 23:33:17 GMT, Werehatrack <[email protected]> wrote:

>On Sat, 26 Jul 2003 15:37:05 -0500, Patrick Lamb <[email protected]> may have said:
>
>>asqui wrote:
>>> larry english wrote:
>>>
>>>>>>how fast do you have to go before the spray from the back wheel can;t make it up to your back?
>>>>>
>>>>>A lot faster than you can safely ride on a wet road.
>>>>
>>>>ha ha.
>>>>
>>>>what i was really thinking of was, air resistance.
>>>>
>>>>sure the spray travels twice as fast at the top of the wheel, etc.
>>>>
>>>>but at some point, you get away from it, because it slows down from air resistance, as you
>>>>speed away.
>>>
>>> [...]
>>>
>>> Not really: it would be right behind you in your slipstream. (This means you'd have to go even
>>> faster to achieve the desired effect.)
>>
>>I think the answer to the original question is pretty close to 0 mph (conversion to metric left as
>>an exercise to the reader!). I find I can go rather slowly and the water doesn't come off the
>>tire, but at any significant speed, I'm gonna get wet.
>
>And it didn't take a government-funded research project to find out, either.

Great idea! Where do I apply for the grant?

 

[Larry English]

"F1" <[email protected]> wrote in message
news:<[email protected]>...
> Even if there is some speed at which that can happen, someone mentioned that it wouldn't be a
> speed you'd want to go on wet road, but since your question about about a dry back, wouldn't you
> be pretty wet up front?

yep. still i was wondering. it;s like a sonic boom, you travel faster than the speed of disturbances
in your medium.

wle.

 

[Asqui]

larry english wrote:
> it;s like a sonic boom, you travel faster than the speed of disturbances in your medium.

When you are creating the disturbances, and the characteristics of said disturbances vary with your
speed, that tends to complicate things quite a bit.

Dani