QR bike philosophy-- long (was "Weight or Aerodynamics")

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Dan Empfie » Sun, 18 Aug 1996 04:00:00


Usually I wouldn't post something like this, as what follows IS going to
be an ad for QR (so stop reading if that's offensive to you).  It seems an
appropriate post because I have argued lately for some design themes that
may not be ultimately defensible in a vacuum, but might make more sense in
the overall context of "why we build our bikes the way we do".

To that end, below are two lists.  The first is WHAT we build:

1. WE BUILD TRIATHLON BIKES, NOT TIME TRIAL BIKES.  A triathlon bike is an
everyday bike, not a three-times-a-year bike.  It is a training AND racing
bike.   It must be durable, carry two water bottles, accept standard
components, it must be able to accept a variety of different tire sizes,
stuff like that.  It must work well on a variety of courses, both flat and
hilly.  If we made a bike simply for racing in Florida, we'd make the seat
angle 80 or 81 degrees.  

2. WE BUILD BIKES ASSUMING THE HIGHEST LEVEL ATHLETE WILL RIDE THEM. For
many or most of our customers, we overbuild our bikes.  Jim Martin brought
up a good point, that most riders really don't need a stiff BB on most
timed courses.  But if you're building bikes for Jurgen Zack or Spencer
Smith, both of whom we've built for, then you need to pay attention to
such things.  And only in the rarest occasions will we do something for a
pro that is different than what we sell over the counter.  We do not have
any pros currently anything other than stock bikes in stock sizes.

Below is a list, in order of importance, of our 10 most important design themes:

1. BIOMECHANICAL EFFICIENCY:  We believe that the PRIMARY purpose of our
bike is to put the rider in the position that allows the maximum delivery
of power.  Those who are arguably the fastest riders in the world in short
course triathlon (Spencer Smith), long course triathlon (Jurgen Zack) and
in pro bike racing (Indurain) are all NOT known for their pretty aero
positions, but for their power positions.  We've worked with two of these
three quite extensively, and trying to make their position more aero
always slows them down if it alters their application of power in the
slightest.

2. AERODYNAMICS OF THE BIKE / RIDER COMPLEX: A standard road frameset
might generate 2 lbs. of drag in a 30 mph headwind, and with a rider
aboard, maybe 10 lb.  With adjustments in rider position that don't
negatively impact biomechanics or ergonomics, this may drop to 8 lb. of
drag.  Aero wheels, aero fork, good helmet, etc., 7 lb. [Next comes the
part that evokes debate].  Aero fork?  We think about 0.2 lb.  Aero
frame?  Anywhere from 0.2 lb less, to 0.2 lb. more, depending on which
"aero" frame.  The above numbers bespeak why we rank putting the rider
into the most aerodynamically position biomechanically tenable above
aerodynamics of the frame itself.

3. COMFORT & ERGONOMICS: We assume that a triathlete's bike is going to
get ridden often, and far.  It doesn't matter how light or aero the bike
is if you're constantly having to adjust yourself in the saddle, and get
out of the aero position.  That REALLY slows you down. The level of
importance we place on ergonomics has led us to re-engineer many of the
components on our kits, and we offer tires, saddles, saddle covers,
pursuit bars, brake levers, and so forth, that we would bother making if
we were simply making road race bikes.

4. HANDLING:  I hearken back to our definition of a tri bike.  When you
race Zofingen, Nice, New Zealand Ironman, Canadian Ironman, World's
Toughest, Wildflower, Donner Lake and such, you get the sense you want a
road bike underneath you.  Not all triathletes will need a bike that
descends, ascends, corners, and brakes, with precision. For races where
this is not a premium, we may not make the best bike. Regarding handling
and fit, frame construction is an issue.  I commented elsewhere about
welding vs. composite construction.  I do not believe an aluminum welded
bike is either better nor worse than carbon.  Carbon lay-up is versatile,
because you can alter shape, weight, and stiffness of a bike almost
infinitely, and it is a good dampener of vibration.  There are two
drawbacks to carbon.  First, its ability to dampen vibration also makes it
a bad spring.  Marty Nothstein's success notwithstanding, steel is a
better spring, and I believe is a more lively material for sprinting and
acceleration.  Second, producing monocoque carbon frames requires molds
which run from $50,000 to $100,000, each size, to make. When you make a
mold, the bike it spits out better be one its maker will be proud of four
or five years down the line.  When we made the first dual 26" steep seat
angle bike in 1988, we weren't sure the design would survive
geometrically, and it didn't.  We've tweaked it almost every year since
then.  Each year we acquire a larger and larger sample set, from which we
draw conclusions about our geometry.  We are sticklers about our bikes
fitting absolutely correctly, maybe more than we need to be.  In any case,
this is the main reason we choose welded technology.  

5. MECHANICAL EFFICIENCY:  We rate this high, and we investigate the
differences in, for example, various chains, with regard to mechanical
efficiency.  But we feel that we have a long way to go.  As an example,
this year we tested various planetary gear systems (in the BB, as opposed
to the more traditional planetary hubs), and we didn't come to any
conclusions yet.  

6. AERODYNAMICS OF THE FRAMESET:  As I've written elsewhere our goal every
year is to effect aerodynamic improvements that don't negatively impact
our first five goals (and, hopefully, goals seven and beyond).  A rider
who lives in Florida may not need to worry as much about goals 1 through
5, and for that rider a more appropriate bike than ours may exist.

7. DURABILITY: This is another reason we choose welded technology.  Not
only the frame itself, but how the parts attach to the frame, can be
tricky when using *** frame materials.  We'd like to think a person
could ride the hell out of our bikes for several years without any
problems.  In the past we've had success and failures in this area, and
each year we try to improve our bikes' longevity.  

8. WEIGHT:  As with goal #6 above, we are interested in making bikes as
light as possible without sacrifice.  Fortunately, when you build with
7000 series aluminum, you can make a pretty light bike without sacrificing
anything.

9. UPGRADE-ABILITY:  We are coming out with a new fork next year, as well
as new aero wheels, blah blah blah.  We have spoken quite a bit, in our
internal meetings, about treating our bike business like the computer
industry, i.e., selling a bike which has "upgrade slots on its
mother-board."  We'd like those who already have a QR to be able to
upgrade their fork, wheels, handlebars, shifting system, saddle, etc., to
something better, instead of buying a new bike every two years.  This
assumes that we and companies we work with (such as HED) commit to
building things which work well with our existing frames.

10. PRICE:  This, of course, has nothing to do with performance, but it is
of interest to us. We sort of obligate ourselves to make a highly
functional bike for around $1,500.  We offer more expensive stuff, and of
course you get diminishing returns for your incrementally larger
purchases.

OTHER BIKES:

Some people have taken umbrage recently when I've discussed other bikes,
and so I thought I'd set the record straight about what I feel about a few
other brands.

KESTREL-- I was accused of saying the KM40 Airfoil was whippy.  I never
said that.  I said it was heavy (compared to other Kestels, which are
usually very light).  I was asked what you "give up" when you use aero
tubes.  I said that in the case of this bike, you give up light weight.
However I rode this bike, and I like it quite a lot, partly because it is
a well made bike, and certainly because for my height (6'2") it fit well.
In general I like Kestrels quite a bit.  I like their rode bikes best,
because they come in a variety of sizes.  Their fork is very good in terms
of comfort.  There are no flies on Kestrel.

FELT-- I commented that I don't like making the downtube aero, because you
trade off BB flex.  Felt must think so too, because he uses a round
downtube for his road race bikes.  I think Felt tri bikes work fine for
lighter riders.  Is Felt's downtube more aero than a round one?  I don't
think appreciably so.  However, I don't know, because I've never seen it
tested. I suspect Felt bikes will have aero seat tubes next year, and
although I don't know how much drag that will reduce, I don't see anything
negative about an aero seat tube, assuming the seatpost is a decent one.

CARBONFRAMES-- I haven't mentioned this bike lately in any posts, but
thought I would, because I don't understand why this bike isn't more
popular.  If there is one bike whose construction I truly appreciate it is
this one.  

DAVIDSON-- This is another bike I really like.  Davidson drops their top
tubes, fairs their headtubes, and although this is a round tube, double
diamond bike, I think if this bike, with a good aero fork, was used as the
"control" bike in the wind tunnel tests it would beat most any aero bike
that had a standard fork, and most aero bikes with an aero fork.

I like Litespeeds somewhat, I'd like them better if their tri bikes were
shorter in the top tube.  Same with Holland.  My favorite builder bar none
is Roland Della Santa, and if I knew exactly what geometry I wanted, and I
didn't work at QR, I'd have him build my a bike.

If I didn't mention it above, then although I might love it as a road race
bike (such as a Trek 5500), I probably don't like it as a tri bike.  

QRman

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Stephen Vansly » Mon, 19 Aug 1996 04:00:00

Dan,
I alway knew you were a philosopher at heart.  Thanks for for sharing
your ideas.  As I'm sure you know, cost is a factor for the the 99% of us
that aren't sponsored or wealthly.  Furthermore, I think it does
effect our triathlon performance as most people would improve their
race times more by spending money on swim coaching, taking a race or
training vacation, or rewarding themselves (and spouses) with dinners
and massages, than they would gain from a 3000$ frameset.



 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Andrew R. Coggan, Ph.D » Tue, 20 Aug 1996 04:00:00

Dan,
        I commend you for having a philosophy behind the design of your bikes, and for being
able to defend it with sound reasoning. Clearly, you must be meeting some needs out there, or
you wouldn't be able to stay in business. Nevertheless, I think it would be interesting to ask
others out there in r.s.t. land to share what they look for in a bike (assuming they've put much
thought into it, rather than just being swayed by marketing or fashion).

So, all of you out there, what do YOU want in a TT/triathlon bike? Here's what I would look for:

1) Geometry/fit: I think Dan's dead on here...if it doesn't have a steep enough seat tube or a
long enough top tube, then you're not going to be able to achieve a good aero position without
compromising handling. "Steep enough" and "long enough" are relative things, of course, but I
like to see at least a 75 or 76 degree seat tube angle, and a top tube equal or longer than the
seat tube (i.e., a "square" frame). The more willing/able you are to adopt an extreme
"Boarman/Pearce" position, the steeper and longer the bike will have to be. All of this, of
course, must be incorporated into the overall design in such a way as to not create a bad
handling bike, which means getting the head angle/fork offset combo right (i.e., enough
trail). In my opinion (based simply on experience with different bikes), a TT/tri bike should be
much slower steering (i.e., more trail) than a track bike, slower than a criterium bike, even
a little slower than a road race/stage race bike, and maybe about like a good touring bike.

The above brings up two points: first, one of my pet peeves about almost all the tri-bikes on
the market is that they don't allow you to lower the stem enough to get a good aero position. It
makes no sense to me that people are spending mucho $$ on a frame specifically for TT/tri's, and
then having to retro-fit a $200 Look Ergo stem to get a good position. It would be much better
if the bike was built with a down-sloping or dropped top tube in the first place, which, as an
added benefit, reduces the length of head tube slamming into the oncoming air molecules...

My other pet peeve is this: since handling depends on the interaction between head tube angle,
wheel size, and fork offset, is it such a good idea to view the fork as something that is
"upgradeable"? Sure, you can build an aftermarket fork with the right amount of offset for the
"average" bike, but I'd rather have one designed specifically for my frame (believe me, I spent
a lot of time, i.e., months, considering things before I changed the fork on my bike!).

2) Functional aerodynamics: Unlike Dan, I believe that there are small but nonetheless
significant gains to be made by paying proper attention to aerodynamics (or at least
significant enough to make some compromises for, which he disagrees with). By "functional", I
mean things that have been "proved" to work, in the context that they are supported by research.
There's quite a bit of wind tunnel data out there, and although Dan would label me naive, I do
not believe that people are just making these things up. So, read, read, read, be skeptical,
etc., but at least be an *educated* consumer.

3) Stiffness: Dan mentions a lot of big name athletes and big name courses, but most people
don't hammer their bikes that hard and aren't buying it for that once-in-a-lifetime chance to do
Zofingen or whatever. I'd argue that adequate stiffness is necessary, yes, but I don't believe
that I would rate it so highly as to be more important than aerodymanics (as Dan does, in his
refusal to sacrifice the stiffness of round tubes for the reduced wind resistance of wing-shaped
ones). Dan might argue that if I were heavier (than 148 lbs) I'd rate stiffness more highly, but
I think the requirement for stiffness depends as much on your power output and riding style as
it does on weight per se...and I can crank a pretty decent TT (40k in <54 min) and torque
the bike pretty hard if I want to. Also, I've seen a lot of thrashin' triathletes who could
probably go faster if they'd just learn to smooth out a little (ask anybody who races cars for a
living - smoother is almost always faster).

4) Reliability: Having broken two carbon frames and an aluminum one, I am definitely a believer
in the philosophy that "steel is real". I wouldn't necessarily steer away from a non-steel bike
if it offered the other things I want, but if I were paying for it out of my own pocket I'd at
least give some thought to reliability of that particular bike, the warranty and reputation of
the manufacturer, etc.

5) Use of standard components: Despite Dan's arguments, I'm not convinced that there are
significant advantages to 650 C wheels, and least not so great as to justify the cost of
replacing all of my wheels and chainrings, and to be saddled with availability problems to boot
(and don't go telling me that 650 C stuff is readily available - I drove all over Houston, one
of the nation's largest cities, two weekends ago, finally finding the 650 C tube I needed at the
4th shop I tried. If you want further proof, check the recurring "Where can I find 650 C stuff?"
thread here on r.s.t.) So, if I had my choice, I'd probably prefer a 700 C wheeled bike, all
other things being equal. At least I'd prefer a choice, i.e., Softride's Solo vs. Traveler. What
I don't like is having the choice made for me, i.e., QR (sorry, Dan).

6) Weight: This is so low on my list of priorities that I'm not sure if it is even worth
mentioning, but I suppose it should be in here somewhere.

So, based on the above, what bike would I buy, IF I were shopping for one? Well, the ***
would be high on the list, but they are no longer in the bike biz, and if I had to pay for it
(rather than having been sponsored by them), I would worry a little about the
reliability/repairability of a welded aluminum frame. Another choice might be the Litespeed
Blade, since from what I've seen reported it seems to provide an aero advantage (at least sans
rider), and I like the corrosion resistance of Ti. However, the bike is expensive, and really
needs an aero fork, too. I'd certainly look at a Zipp, although I'm not sure this long-time
roadie would ever get used to a beam, and in general I'm leery of carbon fiber (although they
seem to have a very good reputation and warranty).

Probably the highest on my list, though, would be a steel bike built out of the True Temper aero
tube set, i.e., a KHS (or a Yamaguchi or Zinn). I think this bike is a real "sleeper". You get
the right geometry and fit (including a dropped top tube), wind-tunnel proven aerodynamic
benefits, the stiffness and reliability of steel, 700 C wheels, and the only downside is that it
weighs more than some of the more *** bikes out there. But, as pointed out repeatedly
throughout this thread, weight is pretty unimportant when you're talking about things that
determine your speed while cycling...

And if I only had about $600 to spend? Well, a QR Special Edition would be perfect, it it
weren't for those pesky 650 C wheels!

I'll be interested to hear what other people have to say.

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by rei.. » Tue, 20 Aug 1996 04:00:00



Quote:
>So, all of you out there, what do YOU want in a TT/triathlon bike? Here's what I would look for:

1) Fit/comfort - otherwise I'll end up not riding it
2) reliability/ease of maintenence
   If I spend serious $ on a bike, I shouldn't have to spend much time
   messing around with it, and when I do, the parts should be readily
   available.
3) efficiency
   correct geometry, stiffness, and aerodynamics work in here (each
   one about 1/2 as important as the last)
4) tradition, I guess I'd call it.  There's no way I'm going to get
   a Zipp or a Powerwong, I'm just too conservative.  The other
   funny frames also put me off.
5) Cost.  Tris are really my main indulgence, so I don;t mind
   spending a lot, but there comes a point where it gets embarassing.

--
Dan Reiley, Ph.D.     Bell Labs       Naperville, IL

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Tim Ivers » Tue, 20 Aug 1996 04:00:00



|1) Geometry/fit: I think Dan's dead on here...if it doesn't have a steep
|2) Functional aerodynamics: Unlike Dan, I believe that there are small but
|3) Stiffness: Dan mentions a lot of big name athletes and big name courses
|4) Reliability: Having broken two carbon frames and an aluminum one, I am
|5) Use of standard components: Despite Dan's arguments, I'm not convinced
|6) Weight: This is so low on my list of priorities that I'm not sure if

I'd rate things a tad differently.

 1. Geo/Fit.
 2. Standard components; ie. absolutely no 650c wheels.
 3. Stiffness/handling -- gotta handle well on twisty hills.
 4. Reliability -- never breaks, never gets flats, etc.. ;-).
 5. Aero.
 6. Weight.

- Tim Iverson

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Dan Empfie » Tue, 20 Aug 1996 04:00:00


Quote:

> But, as pointed out repeatedly throughout this thread, weight is pretty
> unimportant when you're talking about things that determine your speed while
> cycling...

You and I agree that "weight" gets more scrutiny than it deserves.
However, I'd like to suggest thought that in climbing, it is not as
unimportant as some might make it out.  Sometimes you see these formulas
for how little extra time you take to haul a certain amount of extra
weight up an ascent of a particular grade and distance.  The reality of
climbing, however, is that it is not steady state, but a series of
accelerations.  In fact (and Andy, you know more than I about this, so I'd
appreciate your input) the mechanical inefficiencies the body and the bike
make each revolution a new acceleration (not so much on flats, particlarly
on hills).

Therefore, any formula that truly calculates the difference that one pound
of weight would make on an ascent has to take into account the oscillation
in the application of power during each revolution of the pedal stroke.
This doesn't even address tactics, and what happens when the peloton (yes,
triathlons have them too) gets a wild hair.  

To be honest, I haven't paid a lot of attention to my weight argument from
an empirical point of view.  I'm absolutely shooting from the cuff.  I'm
speaking more from the perception of an athlete, regarding the difference
it makes to ride a bike 3 or 4 pounds heavier.  But I'm open to a good
argument.

Quote:
> I like to see at least a 75 or 76 degree seat tube angle, and a top tube

equal > or longer than the seat tube (i.e., a "square" frame). The more
willing/able
Quote:
> you are to adopt an extreme "Boarman/Pearce" position, the steeper and

longer > the bike will have to be.

I don't entirely agree, but I couldn't figure out any good way to answer
this in a text only format.  So a put up a screen on our website.  It is
http://www.rooworld.com/positions.html
It isn't linked to our website, it's sort of stand-alone.

QRman

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Stephen Vansly » Wed, 21 Aug 1996 04:00:00

As I was the one who brought the mathematics into this argument I'll
add a few points on the importance of weight in climbing.  They are
disconnected musings rather than a strong argument for either 'side'.

- What is an important difference is subjective.  One can
argue that a 10s disadvantage in a long hill climb is unimportant over
a long race, particularly if the slower bike has traded this weight
disadvantage for an aero advantage.  This was the point of my original
argument.  I don't think many athletes would give up the extra weight
of aero bars for a faster climbing bike.  The tradeoffs of other
modifications are certainly debatable.  Still, a bike race can be as
much a psychological as a physical game and I don't like looking at a
10s deficit at the same time as my heart rate is maxing out.

- For the record, I have been gulity of employing every time saving
possibility at some point, including a carbon fibre frame, Mavic 190
rims, aero rims, 19mm tires,***tubes, ...., ditching water bottles
on climbs, ...., and (brace yourself) riding with a single chainring.        

- IMHO the mathematics that relate power output and drag coefficients
to steady-state speed are accurate predictors of performance.  But
Dan's point that hill climbing is different from time trialing is
correct, as most riders move the bike from side-to-side in climbing
and the speed is not steady.  An interesting example of climbing
efficiency vs. weight is tandems.  The weight of a tandem is close to
twice the weight of a road bike and you have twice the power, but they
don't climb worth a damn.  On the other hand, they descend like a run
away freight train and if you don't catch the draft on the flats
you'll be dropped quickly.

- What we are lacking is sufficient empirical evidence.  I propose
some road testing this fall after everyone is finished with thier
races.  At my disposal I have two test sites: the Marymoore Velodrome
and the infamous Cougar Mountain climb in the Seattle area.  So who is
up for the challenge?  You're welcome to fly up for the testing Dan,
write it off as a business expense and the local RST gang will take you
out for scenic rides and some great Thai food.


 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by tony sa » Wed, 21 Aug 1996 04:00:00


Quote:



>> But, as pointed out repeatedly throughout this thread, weight is pretty
>> unimportant when you're talking about things that determine your speed while
>> cycling...

>You and I agree that "weight" gets more scrutiny than it deserves.
>However, I'd like to suggest thought that in climbing, it is not as
>unimportant as some might make it out.  Sometimes you see these formulas
>for how little extra time you take to haul a certain amount of extra
>weight up an ascent of a particular grade and distance.  The reality of
>climbing, however, is that it is not steady state, but a series of
>accelerations.  In fact (and Andy, you know more than I about this, so I'd
>appreciate your input) the mechanical inefficiencies the body and the bike
>make each revolution a new acceleration (not so much on flats, particlarly
>on hills).

There are two types of accelerations you have to take into account.

1.  The linear acceleration of the entire weight of the bike.  I think
  from the wind tunnel test data and power calculation formulaes
  published in Inside Tri (or was it Velo News), that a little extra
  weight doesn't have a large effect on the amount of power required
  to move rider and bike.  Fighting drag takes a relatively large
  amount of your power output, unless it's a very steep hill.

2.  The radial acceleration of the bike wheel.  Weight seems to make
  a huge difference here.  You have to constantly accelerate the wheel,
  and the further the weight is from the "center", the more energy it
  takes to accelerate it.  Plus the big killer is, that when you add
  weight, the increase in energy required to accelerate the new weight
  is not a linear function, I think it's something to do with the
  square of the mass (Sorry I can't find my old physics book).

In summary, I believe that compared to the aerodynamic resistance,
frame weight has a relatively small impact, even when climbing.  It's
just like gaining or losing a pound of body weight.

Light wheels are more important, especially light rims.  

Tony

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Marty Mill » Wed, 21 Aug 1996 04:00:00


Quote:

>Those who are arguably the fastest riders in the world in short
>course triathlon (Spencer Smith), long course triathlon (Jurgen Zack) and
>in pro bike racing (Indurain) are all NOT known for their pretty aero
>positions, but for their power positions.  We've worked with two of these
>three quite extensively,...

Is Miguel a nice guy?  I always wondered.  ;)

-----------------------------
Marty Miller

Proprietor of The Triathlete's Web
http://w3.one.net/~triweb

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Marty Mill » Wed, 21 Aug 1996 04:00:00


Quote:
>I like Litespeeds somewhat, I'd like them better if their tri bikes were
>shorter in the top tube.

This explains why I had to go to an 100 for my stem. I've also heard about bad
aerodynamics on the Tachyon.  Do you believe this is accurate, and if so, is it
significant enough to worry about (a new RST rule:  if you post an AD you have
to answer questions like this!)???  Also, on a related note, is there any way
to keep my front derailleur from rubbing on the chain when on my small
chainring???  The angle of the seat tube is not very compatible with a
conventionally mounted front derailleur.

Thanks!

Marty

-----------------------------
Marty Miller

Proprietor of The Triathlete's Web
http://w3.one.net/~triweb

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Dan Empfie » Wed, 21 Aug 1996 04:00:00


Quote:

> As for "mechanical inefficiencies of the body", I don't know of any data

that > really addresses the issue of how accelerating/deaccelerating would
affect VO2 > at a constant power.

I can't address this in a precise way at all, so don't bury me too badly
on this.  I'll state as axiomatic that the body has a mechanical
inefficiency while pedalling the bike, that there are two areas when the
body has a mechanical advantage during one revolution of the pedal stroke,
and inbetween those two points the body cannot sustain the same degree of
force (if you don't agree with this, we can talk about it, hopefully we
can agree on the above, however, and move on).  The Power Cam, BioPace
chainrings, the Drop Center crank, were all attempts to overcome this lack
of constant power output.

When riding on the flat, this inefficiency is not that noticable, because
you don't lose much velocity inbetween the power phases of the pedal
stroke, and so don't have to re-accelerate the bike.  The steeper the
grade during an ascent, the harder it is to keep your velocity up
inbetween power phases. You are not only overcoming the weight of the bike
& rider, you're losing inertia inbetween peak power phases of the pedal
stroke, and you're re-accelerating the bike twice during each pedal
stroke.  And that's in the best of circumstances.  You also have to
re-accelerate the bike when the grade gets momentarily steeper, when you
lose cadence on the gear you're riding, when you're forced by tactics to
increase your velocity, when you change from in the saddle to out, and
back in again, and so on.

Quote:
> Personally, in terms of "feel" I'd rather have a stiff bike than a light one
> for climbing, assuming that I couldn't have both.

I agree entirely.  Fortunately, it isn't a problem having both.
Hearkening back to an earlier thread, though, it only becomes difficult to
have both when the conventional bike is altered in favor of aerodynamics.
Notice I said "difficult", not "impossible" (M. Sholl has caused me to be
more thoughtful in my statements).  

Quote:
> Nice pictures, Dan! I assume that Pauli is the one at the upper right, with
> the best view of his  position? I'd say that his shoulders are at least 4"
> higher than what would result in minimal drag in the wind tunnel (which I
> would argue is optimal, but you wouldn't).

Actually, I would agree with you.  But there is a difference between what
is optimal, and what is sustainable (for a long distance triathlon).  I
think Pauli's position is quite aggressive for a triathlete.  It's not a
Colby Pearce position, but Colby doesn't train and race triathlons.  
Remember a few years ago Glah went to the wind tunnel, and had his
position "optimized".  He dropped about a pound of drag.  But he just
couldn't ride that way, and so moved back to a less aggressive position.

Quote:
> I'd guess that with this setup that my elbow, shoulder, and hip angles
> are all around 100-110 deg. While this is more extreme than what you prefer,

You're the physiologist, and here is where I fear I'm going to get slain.
But here goes:  we see a lot of people who get back pain when they ride,
both inbetween the traps, and even moreso in the low back.  In just about
every case, we can cure these problems by bringing them back to that 90
degree angle between the torso and upper arm.  Why does this help?  My
view (and it is strictly a theory) is that the steeper the seat angle, and
the flatter the back, the more of the rider's weight is suspended over the
front of the bike.  It is upheld in two areas, the spinal erectors in the
back (which cantilever the torso in this position) and the arms.  The
beauty of aero bars is that they suspend the upper body skeletally,
instead of muscularly (the old pursuit bar position suspended the upper
body muscularly).  If the upper arms are perpendicular to the torso in the
aero position (the 90 degree angle I'm talking about), the upper arms are
"columns", supporting most of the weight of the upper body. As you move
the elbows more and more forward, however, the "job" of suspending the
torso shifts more to the spinal erectors.  All the riders in the web page
I put up are Ironman distance competitors.  I believe the distances they
ride guarantee that such a strain on the low back would manifest itself
eventually, which is why they all ride with the right angle I describe.  

Your position is actually similar to what John Cobb feels is correct.
However, he says that when you're riding on the flat you'll move up onto
the nose of your saddle, and so adopt a right angle (much like Pigg
does).  If you share this view, I then think the difference between your
position and mine is nuanced.

QRman

 
 
 

QR bike philosophy-- long (was "Weight or Aerodynamics")

Post by Dan Empfie » Wed, 21 Aug 1996 04:00:00


Quote:

> You're welcome to fly up for the testing Dan,
> write it off as a business expense and the local RST gang will take you
> out for scenic rides and some great Thai food.

There are some occasions when I embrace the scientific method.

QRman