stem backwards ok?

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

Quoted message said:

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

Is there a point to this other than to make a simple idea needlessly
complex? When your front wheel is turning the top is going in the
opposite direction as the bottom. What does this mean for the average
bike rider? Not a whole hell of a lot. You know you are in RBT when
any question that comes within a mile of physics becomes the semantics
argument of the week.

Bill Sornson said:

Marz said:

eddie_1 said:

Hi, i bought a 24" bike for my son who is 9 but it is a bit too big
for him. In order to help with the reach to the handle bars, i was
wondering if it would be ok to install the quill stem backwards?
thanks! ~ed

Quoted message said:

Wow, how much too big for him is the bike, can he even reach the
pedals. Go buy your son a bike that fits you tight wod! And no it's
not a great idea and no he'll not have to steer in the opposite
direction. Maybe buying a really short stem might help or sliding the
seat as far forward as possible. If the seat post has any layback, you
may think about turning it around.

Swap the saddle direction then, too. LOL

Bill "poor kid's got enough problems" S.

Ouch, yes, good point.

Michael Press said:

In article <[email hidden]>,

Barnard Frederick said:

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

Quoted message said:

Quoted message said:

But the handling will be different since turning right will mean
moving the handlebars to the left (and vice versa) rather than the
"usual" arrangement. I don't find that to be a big problem, but then
I ride recumbent bikes, where that arrangement is the norm, and I
already know how to ride "regular" bikes (and still do without
problems switching between them and my recumbents). Your son might be
a different story if he is just learning to ride.

Quoted message said:

It's not a big practical difference, because the same basic arm motions
produce the same result for steering the bike.

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

--
Michael Press

How do some of you folks function during the day, sheesh*3.14.

Yes the stem will travel in a relatively opposite direction if you
switch it from forward to rearward facing. But last time I checked few
folks steer a bike from the end of the stem. With a straight handle
bar you'll still twist (turn, swing) it in the same direction
regardless of stem direction.
To turn right (walking pace, no counter steer)

up ---------------------------down
|
| stem will move clockwise/right
0

0
|
| stem will more clockwise/left
up ---------------------------down

Imagine a big steering wheel on a bike where normal hand postions are
at 10 and 2. All that's really happening when you switch stem
direction is that you're now steering the bike with hands at 8 and 4.

eddie_1 said:

Hi, i bought a 24" bike for my son who is 9 but it is a bit too big
for him. In order to help with the reach to the handle bars, i was
wondering if it would be ok to install the quill stem backwards?
thanks! ~ed

It should be fine -- may look a little strange, but won't really effect
steering much.

On Tue, 01 May 2007 20:48:45 -0700, Michael Press <[email hidden]>

Quoted message said:

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

I disagree. The stem moves exactly the same way. The stem is an axis
which always moves its North point to the right to make a right turn
and its South point to the left to make a right turn. Conventional
stems just trim the axis at the center (head tube) location.
Geometrically speaking, it's still there, and it's always moving the
same way to make the same turn.

still me said:

On Tue, 01 May 2007 20:48:45 -0700, Michael Press <[email hidden]>

Quoted message said:

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

I disagree. The stem moves exactly the same way. The stem is an axis
which always moves its North point to the right to make a right turn
and its South point to the left to make a right turn. Conventional
stems just trim the axis at the center (head tube) location.
Geometrically speaking, it's still there, and it's always moving the
same way to make the same turn.

Whatever. With a long stem backwards one has to move their arms the
opposite direction of what they're used to. That is what matters. Have
you tried it yet?

Greg

--
The ticketbastard Tax Tracker:
http://www.ticketmastersucks.org/tracker.html

Dethink to survive - Mclusky

On Wed, 02 May 2007 12:35:39 -0700, "G.T." <[email hidden]>

Quoted message said:

Whatever. With a long stem backwards one has to move their arms the
opposite direction of what they're used to. That is what matters. Have
you tried it yet?

No, and I don't plan to :-)

Have you actually tried to ride a bike arranged like that?

In article <[email hidden]>,

still me said:

On Tue, 01 May 2007 20:48:45 -0700, Michael Press <[email hidden]>

Quoted message said:

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

I disagree. The stem moves exactly the same way. The stem is an axis
which always moves its North point to the right to make a right turn
and its South point to the left to make a right turn. Conventional
stems just trim the axis at the center (head tube) location.
Geometrically speaking, it's still there, and it's always moving the
same way to make the same turn.

Look at it.

With the stem pointing forward
Right turn -> steering tube rotates clockwise -> stem-bar clamp moves right.

With the stem pointing rearward
Right turn -> steering tube rotates clockwise -> stem-bar clamp moves _left_.

Everybody, if more than one person is saying something
counter-intuitive, it is best not to dismiss them immediately.

--
Michael Press

In article <[email hidden]>,

Bill Sornson said:

Michael Press said:

In article <[email hidden]>,

Barnard Frederick said:

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

> But the handling will be different since turning right will mean
> moving the handlebars to the left (and vice versa) rather than the
> "usual" arrangement. I don't find that to be a big problem, but
> then I ride recumbent bikes, where that arrangement is the norm,
> and I already know how to ride "regular" bikes (and still do without
> problems switching between them and my recumbents). Your son might
> be a different story if he is just learning to ride.

It's not a big practical difference, because the same basic arm
motions produce the same result for steering the bike.

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

Too bad that's not what Victor was taking about. (Hint: he mentioned the
handlebars, even though most bikes only have one, of course.)

The bars move with the stem-bar clamp. The center of mass of the
bars moves rightward in one configuration, leftward in the other
configuration.

--
Michael Press

In article <[email hidden]>,

Barnard Frederick said:

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

Quoted message said:

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

Is there a point to this other than to make a simple idea needlessly
complex? When your front wheel is turning the top is going in the
opposite direction as the bottom. What does this mean for the average
bike rider? Not a whole hell of a lot. You know you are in RBT when
any question that comes within a mile of physics becomes the semantics
argument of the week.

What has this to do with the geometry under discussion?

--
Michael Press

In article
<[email hidden]>,

Marz said:

Michael Press said:

In article <[email hidden]>,

Barnard Frederick said:

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

Quoted message said:

> But the handling will be different since turning right will mean
> moving the handlebars to the left (and vice versa) rather than the
> "usual" arrangement. I don't find that to be a big problem, but then
> I ride recumbent bikes, where that arrangement is the norm, and I
> already know how to ride "regular" bikes (and still do without
> problems switching between them and my recumbents). Your son might be
> a different story if he is just learning to ride.

Quoted message said:

It's not a big practical difference, because the same basic arm motions
produce the same result for steering the bike.

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

--
Michael Press

How do some of you folks function during the day, sheesh*3.14.

Yes the stem will travel in a relatively opposite direction if you
switch it from forward to rearward facing. But last time I checked few
folks steer a bike from the end of the stem. With a straight handle
bar you'll still twist (turn, swing) it in the same direction
regardless of stem direction.
To turn right (walking pace, no counter steer)

up ---------------------------down
|
| stem will move clockwise/right
0

0
|
| stem will more clockwise/left
up ---------------------------down

Imagine a big steering wheel on a bike where normal hand postions are
at 10 and 2. All that's really happening when you switch stem
direction is that you're now steering the bike with hands at 8 and 4.

Nevertheless, on a right turn the bars will shift rightward
overall in one configuration, leftward in the other configuration.

--
Michael Press

In article <[email hidden]>,

Bill Sornson said:

A Muzi said:

Quoted message said:

>> "Victor Kan" <[email hidden]> wrote in message
>> news:[email hidden]...
>>> On May 1, 2:08 pm, "Bill Sornson" <[email hidden]> wrote:
>>> Try it, or just visualize it. Turn the stem around on one of your
>>> bikes so that it points backwards rather than forwards, but keep
>>> your handlebars oriented the same way. Your hand position is now
>>> much more likely to be behind the steering axis rather than in
>>> front of it, especially if it is a flat bar bike (my guess for a
>>> 24" kids bike) or has swept back bars, even on drop bars unless
>>> they have a longer effective reach than the stem length.
>>> Now try turning right. Your hands still sweep kinda clockwise,
>>> but since you're on the other side of the axis, you're moving the
>>> bars to the left rather than to the right.

Quoted message said:

> DI <[email hidden]> wrote:
>> Still doesn't make sense.

Quoted message said:

Ben C wrote:
> Think of a car steering wheel. You turn right. The part of the wheel
> at 12 o'clock moves right, the part at 6 o'clock moves left.
> With a normal stem the handlebars are like a tangent to the steering
> wheel at 12 o'clock, but with a stem pointing backwards they're at 6
> o'clock.
> In both cases you rotate the bars clockwise, but with a normal stem
> the point where the handlebars are attached to the stem moves to the
> right of its original position; with a reversed stem it moves to the
> left.

Bill Sornson said:

OK, that at least makes sense. Yes, the STEM would swing left as
you turn right, and vice versa. That's not what Victor claimed
originally, however. ("But the handling will be different since
turning right will mean moving the /handlebars/ to the left (and
vice versa) rather than the 'usual' arrangement."😉 Italic added.

Victor's description seemed clear to me the first time and still does.
As Chalo notes, a short stem would make the effect minimal but
imagine a 120 stem pointing right at you - get it now? A road bar
might even hit the top tube on its way to the left in a right turn.

Yes...but the BAR still turns in the same direction.

I give up.

REVERSED STEMS FOR EVERYONE! :-D

Two elements of the motion can be teased out. Rotation about the
steering axis and translation wrt the steering axis. The latter
difference is perceptible.

--
Michael Press

In article <[email hidden]>,

Peter Cole said:

eddie_1 said:

Hi, i bought a 24" bike for my son who is 9 but it is a bit too big
for him. In order to help with the reach to the handle bars, i was
wondering if it would be ok to install the quill stem backwards?
thanks! ~ed

It should be fine -- may look a little strange, but won't really effect
steering much.

How do you know? Can you guarantee that when the son tries to ride
a bicycle with a forward directed stem that the son will not have
problems? I think he will.

--
Michael Press

Michael Press said:

In article <[email hidden]>,

Bill Sornson said:

Michael Press said:

In article <[email hidden]>,
Barnard Frederick <[email hidden]> wrote:

> In article <[email hidden]>,
> [email hidden] says...
>
>> But the handling will be different since turning right will mean
>> moving the handlebars to the left (and vice versa) rather than the
>> "usual" arrangement. I don't find that to be a big problem, but
>> then I ride recumbent bikes, where that arrangement is the norm,
>> and I already know how to ride "regular" bikes (and still do
>> without problems switching between them and my recumbents). Your
>> son might be a different story if he is just learning to ride.
>
> It's not a big practical difference, because the same basic arm
> motions produce the same result for steering the bike.

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

Too bad that's not what Victor was taking about. (Hint: he
mentioned the handlebars, even though most bikes only have one, of
course.)

The bars move with the stem-bar clamp. The center of mass of the
bars moves rightward in one configuration, leftward in the other
configuration.

I see your problem. You have more than one handlebar! (And, of course, it
/turns/ the same way regardless of stem orientation.)

Don't worry; you'll get it.

:-P

Michael Press said:

In article
<[email hidden]>,

Marz said:

Michael Press said:

In article <[email hidden]>,
Barnard Frederick <[email hidden]> wrote:

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

>> But the handling will be different since turning right will mean
>> moving the handlebars to the left (and vice versa) rather than the
>> "usual" arrangement. I don't find that to be a big problem, but
>> then I ride recumbent bikes, where that arrangement is the norm,
>> and I already know how to ride "regular" bikes (and still do
>> without problems switching between them and my recumbents). Your
>> son might be a different story if he is just learning to ride.

> It's not a big practical difference, because the same basic arm
> motions produce the same result for steering the bike.

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

--
Michael Press

How do some of you folks function during the day, sheesh*3.14.

Yes the stem will travel in a relatively opposite direction if you
switch it from forward to rearward facing. But last time I checked
few folks steer a bike from the end of the stem. With a straight
handle bar you'll still twist (turn, swing) it in the same direction
regardless of stem direction.
To turn right (walking pace, no counter steer)

up ---------------------------down
|
| stem will move clockwise/right
0

0
|
| stem will more clockwise/left
up ---------------------------down

Imagine a big steering wheel on a bike where normal hand postions are
at 10 and 2. All that's really happening when you switch stem
direction is that you're now steering the bike with hands at 8 and 4.

Nevertheless, on a right turn the bars will shift rightward
overall in one configuration, leftward in the other configuration.

"Shift". "Swing." The OC (original comment) was
TURN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

HTH.

G.T. said:

With a long stem backwards one has to move their arms the
opposite direction of what they're used to.

Absolutely false. Want to turn right? Move your left hand away and your
right hand in. Only difference, really, is the amount of elbow bend.

Oh, great, now there's ANOTHER subject. "Elbows"...

Michael Press said:

In article <[email hidden]>,

still me said:

Michael Press said:

If the stem leaves the steering tube an goes forward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: right.

If the stem leaves the steering tube an goes backward,
then to turn right you rotate the steering tube
clock-wise. What direction does the stem move?
Answer: left.

I disagree. The stem moves exactly the same way. The stem is an axis
which always moves its North point to the right to make a right turn
and its South point to the left to make a right turn. Conventional
stems just trim the axis at the center (head tube) location.
Geometrically speaking, it's still there, and it's always moving the
same way to make the same turn.

Look at it.

With the stem pointing forward
Right turn -> steering tube rotates clockwise -> stem-bar clamp moves
right.

With the stem pointing rearward
Right turn -> steering tube rotates clockwise -> stem-bar clamp moves
_left_.

Everybody, if more than one person is saying something
counter-intuitive, it is best not to dismiss them immediately.

Nice change of subject from the first comment that raised objection. Poster
said the bar /turns/ in a different direction.

It's really not that complicated.

Michael Press said:

In article <[email hidden]>,

Peter Cole said:

eddie_1 said:

Hi, i bought a 24" bike for my son who is 9 but it is a bit too big
for him. In order to help with the reach to the handle bars, i was
wondering if it would be ok to install the quill stem backwards?
thanks! ~ed

It should be fine -- may look a little strange, but won't really
effect steering much.

How do you know? Can you guarantee that when the son tries to ride
a bicycle with a forward directed stem that the son will not have
problems? I think he will.

Of course he won't. He'll TURN the handlebar (singular) the exact same way
and direction as always. The stem's just along for the...ride.

HTH!

Michael Press said:

In article <[email hidden]>,

Bill Sornson said:

A Muzi said:

>>> "Victor Kan" <[email hidden]> wrote in message
>>> news:[email hidden]...
>>>> On May 1, 2:08 pm, "Bill Sornson" <[email hidden]> wrote:
>>>> Try it, or just visualize it. Turn the stem around on one of
>>>> your bikes so that it points backwards rather than forwards,
>>>> but keep your handlebars oriented the same way. Your hand
>>>> position is now much more likely to be behind the steering axis
>>>> rather than in front of it, especially if it is a flat bar bike
>>>> (my guess for a 24" kids bike) or has swept back bars, even on
>>>> drop bars unless they have a longer effective reach than the
>>>> stem length.
>>>> Now try turning right. Your hands still sweep kinda clockwise,
>>>> but since you're on the other side of the axis, you're moving
>>>> the bars to the left rather than to the right.

>> DI <[email hidden]> wrote:
>>> Still doesn't make sense.

> Ben C wrote:
>> Think of a car steering wheel. You turn right. The part of the
>> wheel at 12 o'clock moves right, the part at 6 o'clock moves left.
>> With a normal stem the handlebars are like a tangent to the
>> steering wheel at 12 o'clock, but with a stem pointing backwards
>> they're at 6 o'clock.
>> In both cases you rotate the bars clockwise, but with a normal
>> stem the point where the handlebars are attached to the stem
>> moves to the right of its original position; with a reversed stem
>> it moves to the left.

Bill Sornson wrote:
> OK, that at least makes sense. Yes, the STEM would swing left as
> you turn right, and vice versa. That's not what Victor claimed
> originally, however. ("But the handling will be different since
> turning right will mean moving the /handlebars/ to the left (and
> vice versa) rather than the 'usual' arrangement."😉 Italic added.

Victor's description seemed clear to me the first time and still
does. As Chalo notes, a short stem would make the effect minimal but
imagine a 120 stem pointing right at you - get it now? A road bar
might even hit the top tube on its way to the left in a right turn.

Yes...but the BAR still turns in the same direction.

I give up.

REVERSED STEMS FOR EVERYONE! :-D

Two elements of the motion can be teased out. Rotation about the
steering axis and translation wrt the steering axis. The latter
difference is perceptible.

No difference in the way the handlebar (singular) turns.

"still me" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

On Wed, 02 May 2007 12:35:39 -0700, "G.T." <[email hidden]>

Quoted message said:

Whatever. With a long stem backwards one has to move their arms the
opposite direction of what they're used to. That is what matters. Have
you tried it yet?

No, and I don't plan to :-)

Have you actually tried to ride a bike arranged like that?

Yes, last night.

Greg
--
"What have you got in that paper bag?
Is it a dose of Vitamin C?
Ain't got no time for Western medicine
I am Damo Suzuki" - Mark E Smith