An observations about Q-Factor and Crank Length

Just tried a new set of cranks and I think that I've probably been riding cranks that are a bit
long, most of my life. Not really a big deal since I don't think of myself as particularly small I
was a bit suprised. More importantly I am much more sensitive to a large Q-Factor on long cranks
then on shorter ones. This is not a surprise if you think about but I haven't heard anyone else make
the observation before.

For the details if you care:

I grew up riding on 170mm Campy NR cranks. Still have some bikes with the 170mm Campy NR cranks, one
with 170mm Campy chorus, and my wife's has one with 172.5 Mavic cranks. All the bikes are set up the
same way. My wife and I are almost exactly the same size. We ride each others bikes and switch
places on our tandem without adjustments. I am 5'7.5" and about 147 lbs, normal proportions.

We both really disliked the Mavic cranks--they felt too long and much too wide. When I measured the
Q-Factor I was shocked to discover that they were only 1mm wider then the Chorus. (The Chorus cranks
are 145mm and the NR, 135mm). Apparently we were much more sensitive to the Q-Factor on the longer
cranks. The Chorus cranks feel wide too but tolerable.

I figured if the 172.5mm cranks felt too long, then perhaps I should be riding something shorter the
170s. After looking at various web sites (www.cranklength.info and Zinn's site as well as links I
found there), I decided to try 165mm cranks. My inseam is 30.5" (77.5 cm). The 165mm cranks are
21.3% of my inseam. The Q-Factor of the new cranks is 145mm--the same as the Chorus crank set.

The new cranks are much more comfortable. They do feel shorter but they don't feel very wide at all.
There is less stress on my right knee with the 165mm. My right knee is temperamental due to a
running injury years ago. (I don't mean to imply that shorter cranks are necessarily easier on the
knees, but it works for me.)

I hope to borrow a friend's 172.5 Campy NR cranks with the narrower Q-Factor and see how they feel.

countup2003@yahoo.com (Greg Lewis) wrote in message news:<6d6ec87e.0402101836.514c6833@posting.google.com>...
> Just tried a new set of cranks and I think that I've probably been riding cranks that are a bit
> long, most of my life. Not really a big deal since I don't think of myself as particularly small I
> was a bit suprised. More importantly I am much more sensitive to a large Q-Factor on long cranks
> then on shorter ones. This is not a surprise if you think about but I haven't heard anyone else
> make the observation before.
>
> For the details if you care:
>
> I grew up riding on 170mm Campy NR cranks. Still have some bikes with the 170mm Campy NR cranks,
> one with 170mm Campy chorus, and my wife's has one with 172.5 Mavic cranks. All the bikes are set
> up the same way. My wife and I are almost exactly the same size. We ride each others bikes and
> switch places on our tandem without adjustments. I am 5'7.5" and about 147 lbs, normal
> proportions.
>
> We both really disliked the Mavic cranks--they felt too long and much too wide. When I measured
> the Q-Factor I was shocked to discover that they were only 1mm wider then the Chorus. (The Chorus
> cranks are 145mm and the NR, 135mm). Apparently we were much more sensitive to the Q-Factor on the
> longer cranks. The Chorus cranks feel wide too but tolerable.
>
> I figured if the 172.5mm cranks felt too long, then perhaps I should be riding something shorter
> the 170s. After looking at various web sites (www.cranklength.info and Zinn's site as well as
> links I found there), I decided to try 165mm cranks. My inseam is 30.5" (77.5 cm). The 165mm
> cranks are 21.3% of my inseam. The Q-Factor of the new cranks is 145mm--the same as the Chorus
> crank set.
>
> The new cranks are much more comfortable. They do feel shorter but they don't feel very wide at
> all. There is less stress on my right knee with the 165mm. My right knee is temperamental due to a
> running injury years ago. (I don't mean to imply that shorter cranks are necessarily easier on the
> knees, but it works for me.)
>
> I hope to borrow a friend's 172.5 Campy NR cranks with the narrower Q-Factor and see how
> they feel.

Dear Greg,

Psychology often matters as much as physical dimensions in how things feel to us. Double-blind
testing often shows that we're nowhere near as sensitive as we think.

If the Mavic cranks really do feel "much too wide" compared to the Chorus cranks, but are only 1 mm
wider, then it's likely that either you're being influenced by the labels or else aren't measuring
what really affects your feet.

To illustrate how unlikely it is that either of your feet are sensitive to a single millimeter of
width, hold your hand up in front of the computer screen, spread your thumb and fingers, and try to
hold your thumb and forefinger only a millimeter apart. Most people will find it hard to maintain
this tiny distance without noticeable wavering.

(It's easy to cheat--brace your thumb and forefinger against your middle finger.)

For another example, look down and try to hold the side of your shoe a millimeter from the desk. Or
put a thin envelope between the side of your shoe and the desk--that's about a millimeter wide. Can
you feel the difference in width using your foot?

The Mavic may be a millimeter wider than the Chorus, but I suspect that you're probably feeling
something else, even though you write that the bikes are set up the same way. If you're curious, you
might check the seats, pedals, and the curve and thickness of the cranks for more likely
explanations about why one feels "much too wide" when your first measurement shows only a millimeter
difference.

Carl Fogel

> Psychology often matters as much as physical dimensions in how things feel to us. Double-blind
> testing often shows that we're nowhere near as sensitive as we think.
>
> If the Mavic cranks really do feel "much too wide" compared to the Chorus cranks, but are only 1
> mm wider, then it's likely that either you're being influenced by the labels or else aren't
> measuring what really affects your feet.
>
> To illustrate how unlikely it is that either of your feet are sensitive to a single millimeter of
> width, hold your hand up in front of the computer screen, spread your thumb and fingers, and try
> to hold your thumb and forefinger only a millimeter apart. Most people will find it hard to
> maintain this tiny distance without noticeable wavering.
>
> (It's easy to cheat--brace your thumb and forefinger against your middle finger.)
>
> For another example, look down and try to hold the side of your shoe a millimeter from the desk.
> Or put a thin envelope between the side of your shoe and the desk--that's about a millimeter wide.
> Can you feel the difference in width using your foot?
>
> The Mavic may be a millimeter wider than the Chorus, but I suspect that you're probably feeling
> something else, even though you write that the bikes are set up the same way. If you're curious,
> you might check the seats, pedals, and the curve and thickness of the cranks for more likely
> explanations about why one feels "much too wide" when your first measurement shows only a
> millimeter difference.
>
> Carl Fogel

People keep trying to make feelings go away by demonstrating something with a static test. Better to
demonstrate it by movement and THEN try and figure it out.

While I agree that most of what anyone feels is in their minds, I gotta wonder why it is that people
insist that there's nothing there. Yeah, 1mm in a static test ain't much, try rotating your feet
around at 90rpm and tell me that there's still nothing to it. In this case, not only are the
crankarms 1mm wider, but also another 2.5mm longer. I dare say that if the arms were the same
length, the OP probably wouldn't have noticed as much. But that he did tells me that there's
SOMETHING going on.

There's gotta be more to it than "its in your head, stupid," otherwise we wouldn't keep getting
these kinds of questions.

Mike "Puzzled by the feelings"

"Mike S." <mikeshaw2@coxDOTnet> wrote in message news:<edzWb.61049$F15.59449@fed1read06>...
> > Psychology often matters as much as physical dimensions in how things feel to us. Double-blind
> > testing often shows that we're nowhere near as sensitive as we think.
> >
> > If the Mavic cranks really do feel "much too wide" compared to the Chorus cranks, but are only 1
> > mm wider, then it's likely that either you're being influenced by the labels or else aren't
> > measuring what really affects your feet.
> >
> > To illustrate how unlikely it is that either of your feet are sensitive to a single millimeter
> > of width, hold your hand up in front of the computer screen, spread your thumb and fingers, and
> > try to hold your thumb and forefinger only a millimeter apart. Most people will find it hard to
> > maintain this tiny distance without noticeable wavering.
> >
> > (It's easy to cheat--brace your thumb and forefinger against your middle finger.)
> >
> > For another example, look down and try to hold the side of your shoe a millimeter from the desk.
> > Or put a thin envelope between the side of your shoe and the desk--that's about a millimeter
> > wide. Can you feel the difference in width using your foot?
> >
> > The Mavic may be a millimeter wider than the Chorus, but I suspect that you're probably feeling
> > something else, even though you write that the bikes are set up the same way. If you're curious,
> > you might check the seats, pedals, and the curve and thickness of the cranks for more likely
> > explanations about why one feels "much too wide" when your first measurement shows only a
> > millimeter difference.
> >
> > Carl Fogel
>
> People keep trying to make feelings go away by demonstrating something with a static test. Better
> to demonstrate it by movement and THEN try and figure it out.
>
> While I agree that most of what anyone feels is in their minds, I gotta wonder why it is that
> people insist that there's nothing there. Yeah, 1mm in a static test ain't much, try rotating your
> feet around at 90rpm and tell me that there's still nothing to it. In this case, not only are the
> crankarms 1mm wider, but also another 2.5mm longer. I dare say that if the arms were the same
> length, the OP probably wouldn't have noticed as much. But that he did tells me that there's
> SOMETHING going on.
>
> There's gotta be more to it than "its in your head, stupid," otherwise we wouldn't keep getting
> these kinds of questions.
>
> Mike "Puzzled by the feelings"

Dear Mike,

Neither the feelings nor the questions are stupid.

But the effects are more likely either due to other unmeasured dimension or else inside our heads.

Measure the thickness of the socks that you wear while riding with a pair of calipers.

How much would wearing an extra pair of socks add to the width between your feet or the distance
between your feet and your shoes?

My ordinary medium-weight socks are about 2mm thick.

That is, the single layer of extra material under the soles of my feet lengthens my legs 2mm.
Combined, the extra pair of socks narrow the distance between my ankles a whopping 4mm.

Does anyone believe that wearing a pair of extra socks in cold weather requires a crank with shorter
pedal arms or a narrower spindle?

Doctors and magicians routinely use placebo effects and misdirection to put notions in our heads.
And we do it to ourselves all the time.

If a single millimeter in actual crank width really did feel "much too wide," then Peter Chisholm
would be selling cranks in half-millimeter widths.

A single millimeter is simply too small a distance for us to notice while wearing shoes. It's under
1% of the distance between our ankles while we pedal. Keep in mind, that this means that each ankle
would be only half a millimeter farther out. Our socks and shoes flex more than that.

U.S. shoes come in half-sizes that are about 3-5 mm apart in length and widths A-E that vary
about 5 mm:

http://www.bigfeetstuff.com/ebrannock.htm#metric

The original post's claims look like this when tabulated

length Q-factor comments ------ ------- -------- Campy NR 170.0mm 135mm grew up on
these Campy Chorus 170.0mm 145mm wide but tolerable Mavic 172.5mm 146mm much too wide
new cranks 165.0mm 145mm much more comfortable

Frankly, it looks as length was the real problem, not width. The rider may have been on the verge of
feeling uncomfortable with a 170mm crank, become unhappy with a 172.5mm crank, and felt much better
when he shortened his crank to 165mm. Dropping 7.5mm in length might make a noticeable difference--
it's about 4.4%. But widening a spindle 1 millimeter from 145mm is only about 0.7%

If so, the rider wouldn't be the first person to confuse width and length when something felt
uncomfortable. Or to mention puzzling feelings.

That the rider and his wife can swap bikes and seats on their tandem suggests just how insensitive
we are to such minor variations. They may be "almost exactly the same size,"

different hip widths and leg lengths for the same height.

Carl Fogel

<Big Snip>

I don't know about width, but I sure can tell if I've got thick or thin socks on height-wise!

I figured it out the hard way after a few rides where I had to stop and adjust my saddle up some for
no apparent reason. Things felt strange: too low. Next time I rode the bike with thin cycling socks
on, the saddle was too high. It took several times of this happening for me to figure out the
difference was in my socks!

Now I ride in thin socks and don't worry too much about it.

Yeah, I know I'm talking about mm here. I just happen to pay attention to that kind of thing. Ask
any of my riding friends. I'm not nearly as bad as Eddy Merckx, but I'm persnickity about the seat
position thing.

Mike

Greg Lewis wrote:

> More importantly I am much more sensitive to a large Q-Factor on long cranks then on shorter
> ones. This is not a surprise if you think about but I haven't heard anyone else make the
> observation before.
>
> For the details if you care:
>
> I grew up riding on 170mm Campy NR cranks. Still have some bikes with the 170mm Campy NR cranks,
> one with 170mm Campy chorus, and my wife's has one with 172.5 Mavic cranks. All the bikes are set
> up the same way. My wife and I are almost exactly the same size. We ride each others bikes and
> switch places on our tandem without adjustments. I am 5'7.5" and about 147 lbs, normal
> proportions.
>
> We both really disliked the Mavic cranks--they felt too long and much too wide. When I measured
> the Q-Factor I was shocked to discover that they were only 1mm wider then the Chorus. (The Chorus
> cranks are 145mm and the NR, 135mm). Apparently we were much more sensitive to the Q-Factor on the
> longer cranks. The Chorus cranks feel wide too but tolerable.

Were the pedals and shoes identical on when you switched to the Mavic crank? The "true" Q factor
might be affected greatly by pedals and shoes.

Dave dvt at psu dot edu

I guess my original message was not at all clear, since it seems to have been completely miss
interpreted.

What I was trying to say was that longer cranks will make a too large Q-Factor much more noticable.

My point was the Mavic's "felt" wider but weren't. So I hypothesised that cranks shorter then I was
used to would "feel" narrower, even though all the cranks are essentially the same width. Which is
exactly what happened.

I think 145mm width is a long way from optimal for both me and my wife. Which is why I think I like
the NR 170s (135mm width) but not the Chorus 170s (145mm width).

If you do a deep knee bend with your legs spread too wide you will find there is less strain if you
bend your knees less (compared to how much you bend at the ideal width).

If the Q-Factor is ideal for the rider, then I would not expect the rider to be as sensitive to the
crank length.

Unfortunately I couldn't find 9 speed cranks that were narrower.

"Mike S." <mikeshaw2@coxDOTnet> wrote in message news:<ZaFWb.61347$F15.10488@fed1read06>...
> <Big Snip>
>
> I don't know about width, but I sure can tell if I've got thick or thin socks on height-wise!
>
> I figured it out the hard way after a few rides where I had to stop and adjust my saddle up some
> for no apparent reason. Things felt strange: too low. Next time I rode the bike with thin cycling
> socks on, the saddle was too high. It took several times of this happening for me to figure out
> the difference was in my socks!
>
> Now I ride in thin socks and don't worry too much about it.
>
> Yeah, I know I'm talking about mm here. I just happen to pay attention to that kind of thing. Ask
> any of my riding friends. I'm not nearly as bad as Eddy Merckx, but I'm persnickity about the seat
> position thing.
>
> Mike

Dear Mike,

You may have noticed that things felt somehow different when you wore different socks, but it's
unlikely that the difference involved the height of your seat.

We often feel slightly better when we fiddle with things, even when it turns out that they're not
connected to anything relevant.

"There!" we say, "That's better!" And we certainly feel better. But the bicycle with brand-new brake
cables, handlebar tape, and headset bearings is no faster than it was before.

The wishful-thinking effect is real in that we do indeed feel better after fiddling, but it's common
in experiments for subjects to note small but distinct improvements after they carefully adjust
dials that are not hooked up to anything.

Unless you also adjust your seat height according to the thickness of the shorts that you're wearing
and the wear rate of your undergarments, I suspect that the difference was psychological--your
thicker socks felt funny, and fiddling with your seat merely scratched an ill-defined itch.

If a mechanic had pretended to fiddle with your seat and told you that he had raised it just a hair,
you would probably have been just as happy.

Time to defrag my hard drive. The improvement in speed hasn't been measurable for years, but I just
know that it must be faster--after all, I feel better afterward.

Carl Fogel

dvt <dvt_spam@psu.edu> wrote in message news:<c0gfkr$1e2q$2@f04n12.cac.psu.edu>...
>
> Were the pedals and shoes identical on when you switched to the Mavic crank? The "true" Q factor
> might be affected greatly by pedals and shoes.
>
> Dave dvt at psu dot edu

Same equipment, Time old style pedals, Sidi G2 shoes Any recommondations on a narrow Q-Factor pedal?

countup2003@yahoo.com (Greg Lewis) wrote in message news:<6d6ec87e.0402121705.7ae579be@posting.google.com>...
> dvt <dvt_spam@psu.edu> wrote in message news:<c0gfkr$1e2q$2@f04n12.cac.psu.edu>...
> >
> > Were the pedals and shoes identical on when you switched to the Mavic crank? The "true" Q factor
> > might be affected greatly by pedals and shoes.
> >
> > Dave dvt at psu dot edu
>
> Same equipment, Time old style pedals, Sidi G2 shoes Any recommondations on a narrow Q-
> Factor pedal?

Dear Greg,

Here's a page that lists some narrower BB/crank combinations:

http://www.wisil.recumbents.com/wisi...Crank%20Length

These people are concerned with reducing the frontal area of recumbents rather than comfort, but
they might have what you want.

Remember, no matter what anyone says, it's how it feels to you.

Good luck,

Carl Fogel

Greg Lewis wrote:
> dvt <dvt_spam@psu.edu> wrote in message news:<c0gfkr$1e2q$2@f04n12.cac.psu.edu>...
>
>>Were the pedals and shoes identical on when you switched to the Mavic crank? The "true" Q factor
>>might be affected greatly by pedals and shoes.

> Same equipment, Time old style pedals, Sidi G2 shoes Any recommondations on a narrow Q-
> Factor pedal?

I don't have a ton of experience in this field, but I will tell you what I know. I've used Look,
SPD, and Time MTB style pedals with a few variations on shoes. The combination of Look pedals and a
pair of cheap Nashbar road shoes causes my shoe to rub on the crank. It's really annoying when I
wear booties. I get the same results with Shimano 105 Look-style pedals and a pair of pedals with
the Look logo.

So I'd guess that the cheapo Nashbar shoes on Look pedals is the lowest-Q combination I've found.
Too low, in fact.

Dave dvt at psu dot edu