Numerical Benefit of Drafting

Critter P - - - y,

You talk a lot of **** for an anonymous D3 Wal-Mart parking lot racer. I
understand the basics of drafting, and was asking for more specific
information and sources.

No, I don't race bikes for a living. Because I could get into law school.
So I am sure that you know quite a bit more about bike racing than I do.

-Philip
"crit pro" wrote in message
om...
"Philip W. Moore, Jr." wrote in message
...
Can anybody quantify the advantages of drafting in terms of reduced
effort
while riding in the pack, whether in line or in an echelon? I was asked
this question by a mountain biker and could not answer it.


Pretty easy to see why it would be hard for you to describe the
sensation. Considering you are the WORLDS LARGEST FRED, and probably
can't keep up with the local bicycle touring clubs ice cream social
rides, let alone any competitive level training ride. And for the fact
that the longest you ever stayed in any draft was the first lap of the
Dallas Morning News city criterium citizen's category. And the closest
you ever got to an actual working echelon was watching WCP Spring
Classics DVD's while polishing your bike.

cp

"meb" wrote in message
...

Raoul Duke Wrote:
" Can anybody quantify the advantages of drafting in terms of reduced
effort
while riding in the pack, whether in line or in an echelon? I was
asked
this question by a mountain biker and could not answer it.


Funny you should ask. Outside magazine recently published a brief
article
on the effects of drafting (the recent issue with Gabrielle Reece on
the
cover). According to the article, the second rider in line gets a 17%
advantage, the third rider a 38% advantage, and the fourth a 40%
advantage
(assuming a race pace). Interestingly, the article claims the lead
rider
gets a 3% advantage because the second rider breaks up the drag
vortices
behind the lead rider.


It stands to reason the incremental benefit between the second and
third rider is not going more than the incremental benefit between the
first and second.
Whatever benefit the third rider has is going what the second rider
gives him from channelling through an already reduced air-drag plus the
benefit from the lead rider at a 6-8 foot distance.

At least one of those numbers is out of whack no mater what speed they
are tried, or some differing conditions were present.

It stands to reason that changing a few inputs by about 0.001% won't change
weather predictions from sunny to snowing, too. But it can. You're dealing
with a messy complicated system; common sense won't work well.

In any case, I'd imagine they simply stuck powertaps on four bikes, had them
ride in line for a while in all 24 combinations, and averaged, on a still
day on flat ground (or in a velodrome). Easy enough to set that up, and not
too error prone.

Peter

"meb" wrote in message
...

Raoul Duke Wrote:
" Can anybody quantify the advantages of drafting in terms of reduced
effort
while riding in the pack, whether in line or in an echelon? I was
asked
this question by a mountain biker and could not answer it.


Funny you should ask. Outside magazine recently published a brief
article
on the effects of drafting (the recent issue with Gabrielle Reece on
the
cover). According to the article, the second rider in line gets a 17%
advantage, the third rider a 38% advantage, and the fourth a 40%
advantage
(assuming a race pace). Interestingly, the article claims the lead
rider
gets a 3% advantage because the second rider breaks up the drag
vortices
behind the lead rider.


It stands to reason the incremental benefit between the second and
third rider is not going more than the incremental benefit between the
first and second.
Whatever benefit the third rider has is going what the second rider
gives him from channelling through an already reduced air-drag plus the
benefit from the lead rider at a 6-8 foot distance.

At least one of those numbers is out of whack no mater what speed they
are tried, or some differing conditions were present.

It stands to reason that changing a few inputs by about 0.001% won't change
weather predictions from sunny to snowing, too. But it can. You're dealing
with a messy complicated system; common sense won't work well.

In any case, I'd imagine they simply stuck powertaps on four bikes, had them
ride in line for a while in all 24 combinations, and averaged, on a still
day on flat ground (or in a velodrome). Easy enough to set that up, and not
too error prone.

Peter

meb wrote:


It stands to reason the incremental benefit between the second and
third rider is not going more than the incremental benefit between the
first and second.
Whatever benefit the third rider has is going what the second rider
gives him from channelling through an already reduced air-drag plus the
benefit from the lead rider at a 6-8 foot distance.

At least one of those numbers is out of whack no mater what speed they
are tried, or some differing conditions were present.


I'm pretty sure those numbers were from a peleton, and not a paceline.
I bet Outside jumbled it up.

meb wrote:


It stands to reason the incremental benefit between the second and
third rider is not going more than the incremental benefit between the
first and second.
Whatever benefit the third rider has is going what the second rider
gives him from channelling through an already reduced air-drag plus the
benefit from the lead rider at a 6-8 foot distance.

At least one of those numbers is out of whack no mater what speed they
are tried, or some differing conditions were present.


I'm pretty sure those numbers were from a peleton, and not a paceline.
I bet Outside jumbled it up.

"Benjamin Weiner" wrote in message
om...

A 30% reduction in power is the number that's usually tossed around here.
I'm pretty sure that there are exercise phys studies behind this.

http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=2318782

http://www.ncbi.nlm.nih.gov/entrez/q..._uids=10589873

And there may very well be others of which I am not aware.

Andy Coggan

"Benjamin Weiner" wrote in message
om...

A 30% reduction in power is the number that's usually tossed around here.
I'm pretty sure that there are exercise phys studies behind this.

http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=2318782

http://www.ncbi.nlm.nih.gov/entrez/q..._uids=10589873

And there may very well be others of which I am not aware.

Andy Coggan