Bike fit

Typically, I start with the saddle height-- measured from center of the
BB to the top of the saddle parallel to the seat tube and usually this
is determined not from math but from riding the bike. I set the saddle
to the highest position possible (without rocking my hips when I
peddle), record the height and which let's me monitor my fitness
throughout the year-- the higher I like the saddle the more fit I am.

Anyway...

Once you have the height of the saddle set-- I normally like the saddle
to be (approx) 12cm higher than the top of the bar (road). I like to
have no shims under the bar stem-- therefor that 12cm ratio gives you an
idea how big of a frame you need-- from there the length of the stem is
determined when you have your hands on the drops-- the tops should be
obscure you view of the front hub.

....and that's about it.

Quoted message said:

Ron <[email hidden]> wrote:

Quoted message said:

Some questions:
1) Is seat height typically measured perpindicular to the ground, that
is, not along the line of the seat tube, hitting the ground at an
angle?
2) How is reach typically defined?

Ron said:

I'm working to tune the fit of my existing road bike.

I've been through the fit calculator at Wrench Science (although I need
to get some better measurements and re-run the calculations).

Fit involves more than body measurements. Beware of these online formulas
and calculators.

Quoted message said:

Some questions:
1) Is seat height typically measured perpindicular to the ground, that
is, not along the line of the seat tube, hitting the ground at an
angle?

Always measured along the seat tube. Sometimes measured from center of BB to
top of saddle. Sometimes measured from pedal axis (with crank in-line with
seat tube) to top of saddle.

Best method is to raise saddle until your hips start to rock, then lower a
couple of mm.

Quoted message said:

2) How is reach typically defined? Is it the distance from your sit
bones to the bar, or is it to the brake hoods? Also, is the distance
measured parallel to the ground or is it a direct line from the seat to
the bar or hoods?

Don't know. I don't like the sound of this fit method.

Quoted message said:

It looks (and feels, at this point) like I'm going to need a shorter
stem, probably in the 80mm range. Anyone here build stems from Kirk
Pacenti's kit, or make something similar?

See:
http://www.peterwhitecycles.com/fitting.htm

Forget the formulas. Go with what feels right. First get the saddle position
settled (height, fore-aft, tilt). Then work on reach and bar height. Then go
ride. Tweak as needed.

Art Harris

Re advice to raise seat until hips rocks when pedalling, just an observation
of mine over the years...

For some people that might lead to a saddle that is way too high, simply
because they self adjust so hips don't rock (without realizing it) by
pedalling more toes down as the seat goes up - which of course adds a lot of
length to the leg.

Pierre

Arthur Harris said:

Ron said:

I'm working to tune the fit of my existing road bike.

I've been through the fit calculator at Wrench Science (although I need
to get some better measurements and re-run the calculations).

Fit involves more than body measurements. Beware of these online formulas
and calculators.

Quoted message said:

Some questions:
1) Is seat height typically measured perpindicular to the ground, that
is, not along the line of the seat tube, hitting the ground at an
angle?

Always measured along the seat tube. Sometimes measured from center of BB to
top of saddle. Sometimes measured from pedal axis (with crank in-line with
seat tube) to top of saddle.

Best method is to raise saddle until your hips start to rock, then lower a
couple of mm.

Quoted message said:

2) How is reach typically defined? Is it the distance from your sit
bones to the bar, or is it to the brake hoods? Also, is the distance
measured parallel to the ground or is it a direct line from the seat to
the bar or hoods?

Don't know. I don't like the sound of this fit method.

Quoted message said:

It looks (and feels, at this point) like I'm going to need a shorter
stem, probably in the 80mm range. Anyone here build stems from Kirk
Pacenti's kit, or make something similar?

See:
http://www.peterwhitecycles.com/fitting.htm

Forget the formulas. Go with what feels right. First get the saddle position
settled (height, fore-aft, tilt). Then work on reach and bar height. Then go
ride. Tweak as needed.

Art Harris

Best advice.

I would only admonish to not adjust reach by moving the saddle, which
many people seem to do without consideration of the importance of having
the but back far enough to balance and support the torso/bowling ball
over the front of the bike(muscle tone and tendon/ligament tension).
Most sore/numb hands and neck problems come from too great a reach
and/or too little setback.

The 8cm stem makes it sound like OP might consider a frame with a
shorter tt. Not necessarily, but it hints ....

Robin Hubert

Arthur Harris said:

Ron said:

I'm working to tune the fit of my existing road bike.

I've been through the fit calculator at Wrench Science (although I need
to get some better measurements and re-run the calculations).

Fit involves more than body measurements. Beware of these online formulas
and calculators.

Quoted message said:

Some questions:
1) Is seat height typically measured perpindicular to the ground, that
is, not along the line of the seat tube, hitting the ground at an
angle?

Always measured along the seat tube. Sometimes measured from center of BB to
top of saddle. Sometimes measured from pedal axis (with crank in-line with
seat tube) to top of saddle.

Best method is to raise saddle until your hips start to rock, then lower a
couple of mm.

Quoted message said:

2) How is reach typically defined? Is it the distance from your sit
bones to the bar, or is it to the brake hoods? Also, is the distance
measured parallel to the ground or is it a direct line from the seat to
the bar or hoods?

Don't know. I don't like the sound of this fit method.

Quoted message said:

It looks (and feels, at this point) like I'm going to need a shorter
stem, probably in the 80mm range. Anyone here build stems from Kirk
Pacenti's kit, or make something similar?

See:
http://www.peterwhitecycles.com/fitting.htm

Forget the formulas. Go with what feels right. First get the saddle position
settled (height, fore-aft, tilt). Then work on reach and bar height. Then go
ride. Tweak as needed.

Art Harris

I forgot to include that saddle height can be comfortably determined
experimentally, but most important is the extended angle of the knee
that's important. I think 20-30 degrees is reasonable for most.

Robin Hubert

Ron said:

It looks (and feels, at this point) like I'm going to need a shorter
stem, probably in the 80mm range. Anyone here build stems from Kirk
Pacenti's kit, or make something similar?

Is this a road, mtn or what kind of bike? I'm BRAND new to biking, but
to me, an 80 mm stem seems darn short for a road bike. The implication
is that the top tube and therefore the frame, is too long for you.

My friend who knows his stuff is very critical about the knee angles. He
gets that right then compromises with some other measurements.

"Paul Cassel" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Is this a road, mtn or what kind of bike? I'm BRAND new to biking, but to
me, an 80 mm stem seems darn short for a road bike. The implication is
that the top tube and therefore the frame, is too long for you.

Well, it's all relative, you know. My road bike has an 80mm stem on it. It's
a 50cm frame, so, it's appropriate. But you're right, 80mm might be a little
short on a larger road frame.

Ron said:

All -

I'm working to tune the fit of my existing road bike.

I've been through the fit calculator at Wrench Science (although I need
to get some better measurements and re-run the calculations).

Some questions:
1) Is seat height typically measured perpindicular to the ground, that
is, not along the line of the seat tube, hitting the ground at an
angle?
2) How is reach typically defined? Is it the distance from your sit
bones to the bar, or is it to the brake hoods? Also, is the distance
measured parallel to the ground or is it a direct line from the seat to
the bar or hoods?

It looks (and feels, at this point) like I'm going to need a shorter
stem, probably in the 80mm range. Anyone here build stems from Kirk
Pacenti's kit, or make something similar?

Here's a few web sites to peruse. After you're done see if you need to
ask the same questions.

http://www.bsn.com/Cycling/ergobike.html
http://www.peterwhitecycles.com/fitting.htm
http://www.coloradocyclist.com/BikeFit/
http://www.sheldonbrown.com/frame-sizing.html
http://www.rivendellbicycles.com/html/rr_comfposition.html

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3

Pete said:

Re advice to raise seat until hips rocks when pedalling, just an
observation of mine over the years...

For some people that might lead to a saddle that is way too high, simply
because they self adjust so hips don't rock (without realizing it) by
pedalling more toes down as the seat goes up - which of course adds a
lot of length to the leg.

Pierre

I think a variation on this that works is to adjust seat height until hips
are just beginning to rock when you peddle with the HEELS on the pedals.
This results in a lower setting than when doing this test while pedaling
with the balls of the feet.