Advice Q-factor (tread) spec?

On Sun, 19 Dec 2004 22:02:55 +0100, "Sandy" <[email hidden]>

Quoted message said:

<[email hidden]> a écrit dans le message de :
news:[email hidden]...

Quoted message said:

It's not unusual for us to find that some activity
eventually causes pain, so we change the fit slightly and
feel better--not just because of expectation, but because
the change in fit actually did move things enough to take
the load off a damaged area.

The outcome that we hope for is that this change in fit
fixes things permanently.

But another common outcome is that the new area is slowly
damaged by the same activity, just like the old area, and
we're right back where we started.

You want data ? You have some for the above, or are these homey musings
your idea of data. Frankly, it just seems like you are plowing through
leaves with a feather.

Quoted message said:

It's hard to distinguish fit from fancy, so I'm willing to
ask for details and blind tests. Elsewhere in this thread, a
half-degree change in cleats is predicted to cause pain
within 60 miles.

I guess your blind test is supposed to beat my blind test. And we still
don't know if you ride with cleats, do we. Or if you push it. Did you get
a lot of test subjects' replies to fill a spreadsheet ? or a compost bin ?

Quoted message said:

I'm curious how accurately anyone can even adjust a
cleat--half a degree sounds like a change that requires a
screw adjuster or a clamp-on rod and adjustment-jig on
anything as small as a bicycle pedal.

What level of accuracy did you have in mind ? Or are you just plain calling
me a liar ? When something "sounds like" are you saying it's ballast ? I
think your silly example (static foot shuffling) still is indefensible, that
you don't have any experience with cleat adjustments, or that your skeleton
is Jello-based. I am not defending the Q-factor, but you are making it more
believable the more you write. You don't like the degree changes ? OK, what
about moving cleats forward or backward.

Usually, you are readable, but your reliance on your intuitions is limiting
your reason in this discussion. As I said - good on slime - good on
RoadMaster - failing grade here. Ride a bit - it could help.

Dear Sandy,

You volunteered the claim that a half-degree change in cleat
angle would cause noticeable pain within 100 km of hard
riding.

I didn't see any details of a test, blind or otherwise, to
support what seems on its face to be more likely a
psychological effect rather than a physical effect.

Do you adjust cleats to within a half-degree? If so, how do
you determine which half-degree works best? That is, can you
tell the difference just clipping in, or do you assume that
the angle is the problem if something hurts after 100 km?
Have you done any blind testing?

If you change from Q factor to half-degree cleat swivel to
twice as much swivel as that to moving cleats forward or
backward some undefined amount, it's hard to tell what
you're saying, particularly when it's clouded by what seems
like outraged petulance.

Cheers,

Carl Fogel

In article <[email hidden]>, Sandy says...

Carl Fogel said:

Quoted message said:

I'm curious how accurately anyone can even adjust a
cleat--half a degree sounds like a change that requires a
screw adjuster or a clamp-on rod and adjustment-jig on
anything as small as a bicycle pedal.

Sandy replied:

Quoted message said:

What level of accuracy did you have in mind ?

Clearly Carl echoed you number of half a degree. I am curious too. I would
guess the accuracy of adjusting a cleat with just a hex wrench is on the order
of 10 degrees. Do you use additions tools for one-half degree accuracy?

Sheldon Brown said:

Quoth Tim McNamara:

Quoted message said:

Quoted message said:

Q factor was named as such by Grant Petersen.

James Thomson asked:

Quoted message said:

Are you sure? I'm pretty certain I came across the term in an early edition
of "Richard's Bicycle Book", which was published before Peterson was
anybody.

Grant used this term in that sense in his 1991 Bridgestone catalogue:

http://www.sheldonbrown.com/bridgestone/1991/pages/bridgestone-1991-13.htm

I believe this was the first use of "Q factor" in this sense.

"Q factor" already existed with a totally different meaning as a part of
FitKit lingo, being related to the ratio of femur length to total leg
length.

I suspect that Grant may have heard then forgotten the term in the
FitKit context, and then didn't recognize it when it popped back into
his head later.

Sheldon "Tread" Brown
+---------------------------------------------------+
| Originality is the fine art of remembering |
| what you hear but forgetting where you heard it. |
| -- Laurence Peter |
+---------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Dear Tim and Sheldon,

The duck-derived explanation of Q-factor is the nicest thing
that I've read all day--I'd never even wondered what the
damned Q meant!

Thanks for the grin,

Carl Fogel

<[email hidden]> a écrit dans le message de :
news:[email hidden]...

Quoted message said:

Dear Sandy,

You volunteered the claim that a half-degree change in cleat
angle would cause noticeable pain within 100 km of hard
riding.
I didn't see any details of a test, blind or otherwise, to
support what seems on its face to be more likely a
psychological effect rather than a physical effect.

Could the same be said of you sitting on your stool ? And you have
absolutely no idea - other than the arrogant surmise imputed - that it was
psychological. I also didn't pretend to have offered a "scientific sitting
on the stool test", that lacked even your own results, let alone
confirmations.

Quoted message said:

Do you adjust cleats to within a half-degree? If so, how do
you determine which half-degree works best? That is, can you
tell the difference just clipping in, or do you assume that
the angle is the problem if something hurts after 100 km?
Have you done any blind testing?

Nope - riding. And you may notice, that your mention of just over a
fraction of a millimetre change in the toe location doesn't bear the scale
of where the heel is, or the factual change in comfort. You also have not
said that fore-aft relocation of the cleat is not perceptible. You also
don't tell us if you use cleats, which ones they are, and if you can enter
them (if any) blind. All of which suggests you are hiding your ignorance
behind stage props in your garage.

Quoted message said:

If you change from Q factor to half-degree cleat swivel to
twice as much swivel as that to moving cleats forward or
backward some undefined amount, it's hard to tell what
you're saying, particularly when it's clouded by what seems
like outraged petulance.

I guess this answers the question. You don't use cleats. Stick with the
RoadMaster. Keep writing. They say you should write what you know. I'm
not a technical bicycle writer - just a looong term bicycle racer and rider.
If you claim my half-degree is an exaggeration, perhaps it was a too-fine
measurement. On the other hand, it seems there are a lot of riders, and
writers here, who take positioning seriously. Not only the formulae that
come out of bike fit computer programs, but also those that work best for
them.

Next, you may want to address how unlikely it is that your [censored] will line
up perfectly on that stool of yours, on repeated tries. Some folks like to
have their saddles in the right position for them, and really do feel
changes. But such declarations won't dent your approach, I suspect.

Petulance ? I suspect you felt the need to stab back. OK, fair fight. You
are entitled. But it wasn't petulance, but the sad feeling I got when
reading your inane tract. The Q-factor is not the issue, except for its use
as a marketing gimmick. There, we could find accord. But body dynamics all
point to the fact that being in a good position on the bike, by whatever
means achieved, leads to greater satisfaction and performance. Or did you
want to have a go at the concept of bike-fit also being a gimmick ?

--
Bonne route,

Sandy
Verneuil-sur-Seine FR

"Ed" <[email hidden]> a écrit dans le message de :
news:[email hidden]...

Quoted message said:

In article <[email hidden]>, Sandy says...

Carl Fogel said:

Quoted message said:

I'm curious how accurately anyone can even adjust a
cleat--half a degree sounds like a change that requires a
screw adjuster or a clamp-on rod and adjustment-jig on
anything as small as a bicycle pedal.

Sandy replied:

Quoted message said:

What level of accuracy did you have in mind ?

Clearly Carl echoed you number of half a degree. I am curious too. I
would
guess the accuracy of adjusting a cleat with just a hex wrench is on the
order
of 10 degrees. Do you use additions tools for one-half degree accuracy?

Fair question. My half-degree comment was taken as though it is both a
universal sensitivity measure, and perhaps too literally. I try to replace
cleats exactly where the old ones were. This rarely is perfectly
successful, on first try. On those rare occasions, they feel fine. More
typically, it takes several goes, given my non-professional manual skills,
wax slippage, and just plain inattention.

I wish that I had hex-head screws for the look cleats - who makes them ?

Perhaps my grumpiness is due to old cartilege and old bones. Or to the lack
of sunlight in this season. Sorry.
--
Bonne route,

Sandy
Verneuil-sur-Seine FR

On Mon, 20 Dec 2004 01:20:19 +0100, "Sandy" <[email hidden]>

Quoted message said:

<[email hidden]> a écrit dans le message de :
news:[email hidden]...

Quoted message said:

Dear Sandy,

You volunteered the claim that a half-degree change in cleat
angle would cause noticeable pain within 100 km of hard
riding.
I didn't see any details of a test, blind or otherwise, to
support what seems on its face to be more likely a
psychological effect rather than a physical effect.

Could the same be said of you sitting on your stool ? And you have
absolutely no idea - other than the arrogant surmise imputed - that it was
psychological. I also didn't pretend to have offered a "scientific sitting
on the stool test", that lacked even your own results, let alone
confirmations.

Quoted message said:

Do you adjust cleats to within a half-degree? If so, how do
you determine which half-degree works best? That is, can you
tell the difference just clipping in, or do you assume that
the angle is the problem if something hurts after 100 km?
Have you done any blind testing?

Nope - riding. And you may notice, that your mention of just over a
fraction of a millimetre change in the toe location doesn't bear the scale
of where the heel is, or the factual change in comfort. You also have not
said that fore-aft relocation of the cleat is not perceptible. You also
don't tell us if you use cleats, which ones they are, and if you can enter
them (if any) blind. All of which suggests you are hiding your ignorance
behind stage props in your garage.

Quoted message said:

If you change from Q factor to half-degree cleat swivel to
twice as much swivel as that to moving cleats forward or
backward some undefined amount, it's hard to tell what
you're saying, particularly when it's clouded by what seems
like outraged petulance.

I guess this answers the question. You don't use cleats. Stick with the
RoadMaster. Keep writing. They say you should write what you know. I'm
not a technical bicycle writer - just a looong term bicycle racer and rider.
If you claim my half-degree is an exaggeration, perhaps it was a too-fine
measurement. On the other hand, it seems there are a lot of riders, and
writers here, who take positioning seriously. Not only the formulae that
come out of bike fit computer programs, but also those that work best for
them.

Next, you may want to address how unlikely it is that your [censored] will line
up perfectly on that stool of yours, on repeated tries. Some folks like to
have their saddles in the right position for them, and really do feel
changes. But such declarations won't dent your approach, I suspect.

Petulance ? I suspect you felt the need to stab back. OK, fair fight. You
are entitled. But it wasn't petulance, but the sad feeling I got when
reading your inane tract. The Q-factor is not the issue, except for its use
as a marketing gimmick. There, we could find accord. But body dynamics all
point to the fact that being in a good position on the bike, by whatever
means achieved, leads to greater satisfaction and performance. Or did you
want to have a go at the concept of bike-fit also being a gimmick ?

Dear Sandy,

No, we are not in accord about the Q-factor being a
marketing gimmick.

What I wondered about was at what point an asymmetry could
be noticed. I'm skeptical about the idea that one pedal
being 5 mm further away from the seat post can be detected
blindly, as opposed to being a source of psychological
torment when known.

I'm willing to be convinced otherwise, but obviously it
would take someone with an understanding of what blind
testing is and some data other than vague anecdote.

Carl Fogel

Quoted message said:

Matt O'Toole said:

Mike Jacoubowsky said:

If it's not causing any issues, I'd ignore it. An awful lot of
people go from mountain bikes, with "Q" factors all over the map,
to riding a road bike, where the "Q" factor can be dramatically
narrower... with no ill effect. I just checked, and even my double
(compact) FSA carbon cranks are offset more on the chainring side
than the opposite.

Generally I think people make way too much of Q-factor. IMO the
"issue" was invented by bike magazine and advertising writers
scraping the bottom of the barrel for something to write about. I
think most people would never notice the difference unless you told
them, even those who make a big stink about it. And even those who
notice probably wouldn't mind, unless someone had told them it
mattered. Like you said, "to no ill effect." It never mattered to
anyone before the early 90s, when ultra-nerdy gearhead magazines
like Bicycle Guide, and salesmen like Grant Peterson, started
harping on it.

Personally, I don't give a damn how far apart the pedals are, as
long as they're symmetric! I can feel 5mm of asymmetry, and it
drives me nuts.

Matt O.

Dear Matt,

I'd be curious to see if anyone can sit on half a dozen
bikes and tell which ones have their pedals offset 5 mm from
the center of the seat.

There's undoubtedly a point at which an asymmetry is
noticeable (the just-noticeable-difference is often
studied), but sensitivity claims on rec.bicycles.tech are
often startling.

I'd expect to find that those gnarly things on the ends of
our legs are not quite as sensitive as the pea-sensing part
of the fairy-tale princess, particularly when hidden inside
socks and shoes.

Lacking six bikes with offset pedals, here's an alternative
test.

Sit in a chair, make a mark on the floor, and place your
feet on the floor as comfortably and symmetrically as you
can.

Take a pen and mark the inner edge of one shoe with a pen
and make a mark where it touches the floor.

Close your eyes and move that foot around a little
bit--gently, nothing wild or dramatic, just pat the floor
and move your shoe around randomly.

(No fair putting your hands on your knees as guides--not
that it helps much.)

After a dozen taps, move your foot back to where it feels
comfortable and symmetrical again.

Open your eyes and see how close the mark on your shoe is to
the mark on the floor.

Now without moving your foot, close your eyes again, and do
some more delicate pawing at the ground--try not to move
more than an inch in any direction--and then return your
foot to wherever it feels comfortable and symmetrical.

Open your eyes again. A minute or two of this should give
you a good idea of how sensitive your feet are in relation
to each other.

You could also add a long central on the floor, make truly
symmetrical marks to either side, place your feet in
theoretical bliss, close your eyes, drum both feet
simultaneously, and find out that most people are actually
slightly lopsided.

This is true.

Without taking your test, I don't think I'd be able to tell

Quoted message said:

Carl Fogel

Quoted message said:

I'd be curious to see if anyone can sit on half a dozen
bikes and tell which ones have their pedals offset 5 mm from
the center of the seat.

I bet I could after pedaling around a bit. I always do. Of course this assumes
SPD pedals, which don't allow the feet to compensate.

Quoted message said:

There's undoubtedly a point at which an asymmetry is
noticeable (the just-noticeable-difference is often
studied), but sensitivity claims on rec.bicycles.tech are
often startling.

I'd expect to find that those gnarly things on the ends of
our legs are not quite as sensitive as the pea-sensing part
of the fairy-tale princess, particularly when hidden inside
socks and shoes.

Lacking six bikes with offset pedals, here's an alternative
test.

Sit in a chair, make a mark on the floor, and place your
feet on the floor as comfortably and symmetrically as you
can.

Take a pen and mark the inner edge of one shoe with a pen
and make a mark where it touches the floor.

Close your eyes and move that foot around a little
bit--gently, nothing wild or dramatic, just pat the floor
and move your shoe around randomly.

(No fair putting your hands on your knees as guides--not
that it helps much.)

After a dozen taps, move your foot back to where it feels
comfortable and symmetrical again.

Open your eyes and see how close the mark on your shoe is to
the mark on the floor.

Now without moving your foot, close your eyes again, and do
some more delicate pawing at the ground--try not to move
more than an inch in any direction--and then return your
foot to wherever it feels comfortable and symmetrical.

Open your eyes again. A minute or two of this should give
you a good idea of how sensitive your feet are in relation
to each other.

You could also add a long central on the floor, make truly
symmetrical marks to either side, place your feet in
theoretical bliss, close your eyes, drum both feet
simultaneously, and find out that most people are actually
slightly lopsided.

This is true.

I'm sure I wouldn't be able to detect the asymmetry while just sitting on a
bike. I'd have to be pedaling awhile. In every case I've detected it without
fail, within a few minutes. The reasons for the asymmetry have been either a BB
axle that's been put back in the wrong way, or a 68mm BB in a 73mm BB shell.
Maybe I'm sensitive to this BB issue because my personal asymmetry is skewed in
the opposite direction. I'm just as skeptical about people's claimed
sensitivities to such things -- like Q-factor.

Matt O.

Matt O'Toole said:

[email hidden] wrote:

[snip]

Quoted message said:

Quoted message said:

. . . most people are actually
slightly lopsided.

This is true.

I'm sure I wouldn't be able to detect the asymmetry while just sitting on a
bike. I'd have to be pedaling awhile. In every case I've detected it without
fail, within a few minutes. The reasons for the asymmetry have been either a BB
axle that's been put back in the wrong way, or a 68mm BB in a 73mm BB shell.
Maybe I'm sensitive to this BB issue because my personal asymmetry is skewed in
the opposite direction. I'm just as skeptical about people's claimed
sensitivities to such things -- like Q-factor.

Matt O.

Dear Matt,

Aha! I think that I misunderstood you.

I assumed that you meant that only one pedal bent in or out
5mm from where it should be, either due to sloppy
manufacturing or a crash.

But the idea of a reversed BB spindle, if I'm following you,
actually makes things worse. Both pedals are shifted 5mm in
the same direction, right?

|.....x+5mm-----BBshell-----justx| right way
c
e
n
t
e
r
|xtsuj-----llehsBB-----mm5+x.....| reversed

The ASCII diagram above is not to any scale, but is this
roughly what you have in mind?

Carl Fogel

Matt O'Toole said:

Quoted message said:

I'd be curious to see if anyone can sit on half a dozen bikes and
tell which ones have their pedals offset 5 mm from the center of
the seat.

I bet I could after pedaling around a bit. I always do. Of course
this assumes SPD pedals, which don't allow the feet to compensate.

Quoted message said:

There's undoubtedly a point at which an asymmetry is noticeable
(the just-noticeable-difference is often studied), but sensitivity
claims on rec.bicycles.tech are often startling.

Yes, they are. However, it is reasonable to expect that experienced
cyclists would have a smaller threshhold of sensitivity than new
cyclists might. But still, there's going to be a lower limit that is
biologically imposed. People who claim to feel 1 mm differences are
fooling themselves, I suspect.

Quoted message said:

Quoted message said:

I'd expect to find that those gnarly things on the ends of our legs
are not quite as sensitive as the pea-sensing part of the
fairy-tale princess, particularly when hidden inside socks and
shoes.

The perception would not be so much in the feet but in the knees and
hips. We can perceive very small changes in the angle of joints,
which is what allows us motor control. Can you wiggle your foot at
the ankle back and forth 5 mm? Most people can,but you can move your
index finger back and forth about 1 mm quite accurately, as different
body areas have different "resolution" of data discrimination.
There's lots of interesting research on this. Now, compare this ti
oving your knee- how finely can you control foot movement with your
knee? In my informal estimate, in my case, about 4-5 mm unless I'm
concentrating really hard. This suggests to me that the threshhold of
perception for displacement of the foot is relatively large and that 5
mm might not be directly perceived. I don't know of any specific
research on this, but I'd be surprised if it hadn't been done.

(There is a confound in this, though, as you can use visual
observation to perform motor control very finely. If you put your
hand under a magnifying glass, you can make even finer movements
accurately which is how dentists and vascular surgeons do their work
which requires tiny movements. Close your eyes and have someone else
measure your movements).

Quoted message said:

Quoted message said:

Lacking six bikes with offset pedals, here's an alternative test.

Sit in a chair, make a mark on the floor, and place your feet on
the floor as comfortably and symmetrically as you can.

Take a pen and mark the inner edge of one shoe with a pen and make
a mark where it touches the floor.

Close your eyes and move that foot around a little bit--gently,
nothing wild or dramatic, just pat the floor and move your shoe
around randomly.

(No fair putting your hands on your knees as guides--not that it
helps much.)

After a dozen taps, move your foot back to where it feels
comfortable and symmetrical again.

Open your eyes and see how close the mark on your shoe is to the
mark on the floor.

Now without moving your foot, close your eyes again, and do some
more delicate pawing at the ground--try not to move more than an
inch in any direction--and then return your foot to wherever it
feels comfortable and symmetrical.

Open your eyes again. A minute or two of this should give you a
good idea of how sensitive your feet are in relation to each other.

You could also add a long central on the floor, make truly
symmetrical marks to either side, place your feet in theoretical
bliss, close your eyes, drum both feet simultaneously, and find out
that most people are actually slightly lopsided.

This is true.

Very interesting procedure, Carl. You are right in that most people
are lopsided both in terms of leg position from the medial as well as
foot angle. My right leg, for example, is much more duck-footed than
my left both on the bike and sitting with my feet off the ground.

Quoted message said:

I'm sure I wouldn't be able to detect the asymmetry while just
sitting on a bike. I'd have to be pedaling awhile. In every case
I've detected it without fail, within a few minutes. The reasons
for the asymmetry have been either a BB axle that's been put back in
the wrong way, or a 68mm BB in a 73mm BB shell. Maybe I'm sensitive
to this BB issue because my personal asymmetry is skewed in the
opposite direction. I'm just as skeptical about people's claimed
sensitivities to such things -- like Q-factor.

Well, dynamic perception can be quite accurate. In my case, however,
I tend to base my judgments about Q factor and the like on how my
knees feel after 50-100 miles. That's how I've arrived at my "ideal"
Q factor of 140 mm (not possible with Shimano or most aftermarket
cranks, but standard on modern Campy). It's not that it feels
particularly different while riding (although the difference between a
165 mm Q factor and 140 mm is directly noticeable to me) but my knees
feel good at the end of a long ride with the 140 mm Q factor and they
hurt with the 165 mm Q factor. They even hurt a little with a 150 mm
Q factor, but it's minor and not lasting.

Tim-<< Huh, I notice these differences changing from one type of shoe to
another.

Quoted message said:

Quoted message said:

<BR><BR>

I said, I notice they are different but one isn't 'better' than another. My two
bicycles have different standovers and I can tell, but one isn't 'better' than
the other. I still think way to much is made of q factor. Great big ones or
tiny narrow ones 'may' be a problem, but there is definately a 'range' where
small variances will make little difference.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

Sheldon Brown said:

Grant used this term in that sense in his 1991 Bridgestone catalogue:

http://www.sheldonbrown.com/bridgestone/1991/pages/bridgestone-1991-13.htm

Quoted message said:

I believe this was the first use of "Q factor" in this sense.

To quibble, that article does mention an earlier occurrence ('Bicycle
Guide', Aug. '90).

I'm still convinced I'd come across the term used in this context prior to
that, but I've been equally convinced and wrong before. Certainly, there's
no mention that I can find in the copy of Richard's Bicycle Book that I
have to hand (1979), which is where I thought I'd first encountered its
use, and the first Usenet reference I've found is June 1991 (from Phil
Etheridge in New Zealand).

James Thomson