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  #11  
Old October 12th 19, 11:18 AM posted to rec.bicycles.tech
Tosspot[_3_]
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Posts: 1,349
Default Beginner question

On 12/10/2019 00:46, Joy Beeson wrote:

It's been half a century since I needed the information, so I'm not
sure. Is a nineteen-inch bicycle frame nineteen inches from the
center of the bottom bracket to the center of the seat cluster?
"Center" defined as the middle of the top tube.


I believe this to be the case on older flat top tubes, but these days
the stack and reach seem to be a better flavour.

I measured my Fuji at 20.5 inches, and the guy I stole it from said
"twenty-one inches" sounded familiar.

To the top of the top tube seems more logical, since it's the
stand-over height one is interested in -- a fat-tube aluminum bike
would measure undersized if measured to the middle.


https://www.cyclingabout.com/underst...rame-geometry/

When I was thirty and forty and sixty I didn't mind that he's an inch
taller than me, but now that I'm seventy-nine, I've fallen over while
mounting twice, and think it's time to put the word out that I'm in
the market for an elderly bike that is compatible with my elderly
components.

But I have to say what size I want.


Ads
  #12  
Old October 12th 19, 01:19 PM posted to rec.bicycles.tech
[email protected]
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Posts: 29
Default Beginner question

Hi Joy, you mentioned that you thought a shorter seat tube implied a shorter to tube. Sort of. You'll find a lot of bikes these days have sloping top tubes and define both the top tube and seat tube as 'effective' length. In many cases manufacturers are only making small, medium, and large frames. The 'cockpit' fitting comes by fitting the correct stem and seatpost. Your best bet would be to get fitted at a reputable shop. If that isn't practical, there are on-line tools where you enter your measurements like inseam, torso length, and arm length, and it will suggest a frame size and stem. From there you would have to do some additional math is your choosing a non traditional frame design. If you let us know if some specifics, I'm sure there is enough expertise here to guide you in the right direction
  #13  
Old October 12th 19, 02:28 PM posted to rec.bicycles.tech
AMuzi
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Posts: 10,772
Default Beginner question

On 10/11/2019 5:46 PM, Joy Beeson wrote:

It's been half a century since I needed the information, so I'm not
sure. Is a nineteen-inch bicycle frame nineteen inches from the
center of the bottom bracket to the center of the seat cluster?
"Center" defined as the middle of the top tube.

I measured my Fuji at 20.5 inches, and the guy I stole it from said
"twenty-one inches" sounded familiar.

To the top of the top tube seems more logical, since it's the
stand-over height one is interested in -- a fat-tube aluminum bike
would measure undersized if measured to the middle.

When I was thirty and forty and sixty I didn't mind that he's an inch
taller than me, but now that I'm seventy-nine, I've fallen over while
mounting twice, and think it's time to put the word out that I'm in
the market for an elderly bike that is compatible with my elderly
components.

But I have to say what size I want.


Engineering drawings show tube intersections and some brands
list dimensions all center to center, in this case center of
BB to center of top tube/seat tube joint.

A more common specification is a mix of tube centers (almost
all top tube specifications are center to center, like
wheelbase) and then seat tube size as BB center to top of
seat cluster. Why? I have no idea but that's the dominant spec.

Most road/tour frames list in centimeters, most offroad list
in inches. Why? I have no idea.

In our modern world, few frames have level top tubes (this
is generally a positive feature) so bicycle sales flacks
often list _two_ seat tube sizes, actual and what it would
be if the top tube were level. It's become so numbingly
complex that the better part of valor seems to be
XS-S-M-L-Xl which works very well (more sales, fewer knotted
eyebrows)

So much for discussion of theory after 100+ years of random
practice and flailing.

In our age group, I suggest you look at 'open' or 'ladies'
style frames in a medium size. Given the season, you'll get
some attention in a bike shop and as the saying goes it
doesn't cost to look. A test ride or two will also be useful
I think.

Note a few points:
1. There are not many mixtes made now. Get over it. Open
frames may be aesthetically different:
http://www.yellowjersey.org/WFDJHZ.JPG
http://www.yellowjersey.org/wfdopna2.jpg
but your flexibility and limberness probably won't improve
with time.
2. I assume you're looking at upright handlebars rather than
road (drop) bars. The large offroad market means you can
get matching quality compatible shifters for most popular
road gear systems. Flat or upright bars do not mean a lower
quality bike.
http://www.yellowjersey.org/nirofla2.jpg
3. Sporty looking bikes for younger people have low straight
handlebars. It's quick and cheap to add some height with a
handlebar swap. Bonus- riser bars adjust fore and aft with
an allen key in seconds.
4. If you have higher closer handlebars, more of your weight
shifts back, onto the saddle. Generally a wider saddle is
indicated AEBE.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #14  
Old October 12th 19, 03:42 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 7,668
Default Beginner question

On 10/12/2019 1:56 AM, Sir Ridesalot wrote:

We always referred to bicycles with a double sloping top tube that ws attached to both the seat tube and the dropouts as a MIXTE frame. If the bicycle had only one strongly sloping top tube that ended at the seat tube and did not go to the dropouts, we referred to that as a LADY'S frame. Technically speaking Mixte and Lady's frames are NOT the same thing.


Another possibility is a frame that uses a more-or-less standard
diameter tube running from the head tube to a low point on the seat
tube; then extends that to the rear dropouts via two small diameter
tubes. Sort of a blending of the lady and mixte frame.

I suspect that this design would be considerably more rigid than the
classic twin-tube mixte.

My wife rode a twin-tube mixte frame for over ten years. (That bike has
now been passed on to other members of the extended family.) We learned
the hard way that a mixte is nowhere near as rigid as a normal diamond
frame - for example, when carrying loaded rear panniers.

--
- Frank Krygowski
  #15  
Old October 12th 19, 05:51 PM posted to rec.bicycles.tech
Andre Jute[_2_]
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Posts: 9,319
Default Beginner question

On Saturday, October 12, 2019 at 2:28:00 PM UTC+1, AMuzi wrote:
On 10/11/2019 5:46 PM, Joy Beeson wrote:

It's been half a century since I needed the information, so I'm not
sure. Is a nineteen-inch bicycle frame nineteen inches from the
center of the bottom bracket to the center of the seat cluster?
"Center" defined as the middle of the top tube.

I measured my Fuji at 20.5 inches, and the guy I stole it from said
"twenty-one inches" sounded familiar.

To the top of the top tube seems more logical, since it's the
stand-over height one is interested in -- a fat-tube aluminum bike
would measure undersized if measured to the middle.

When I was thirty and forty and sixty I didn't mind that he's an inch
taller than me, but now that I'm seventy-nine, I've fallen over while
mounting twice, and think it's time to put the word out that I'm in
the market for an elderly bike that is compatible with my elderly
components.

But I have to say what size I want.


Engineering drawings show tube intersections and some brands
list dimensions all center to center, in this case center of
BB to center of top tube/seat tube joint.

A more common specification is a mix of tube centers (almost
all top tube specifications are center to center, like
wheelbase) and then seat tube size as BB center to top of
seat cluster. Why? I have no idea but that's the dominant spec.

Most road/tour frames list in centimeters, most offroad list
in inches. Why? I have no idea.

In our modern world, few frames have level top tubes (this
is generally a positive feature) so bicycle sales flacks
often list _two_ seat tube sizes, actual and what it would
be if the top tube were level. It's become so numbingly
complex that the better part of valor seems to be
XS-S-M-L-Xl which works very well (more sales, fewer knotted
eyebrows)

So much for discussion of theory after 100+ years of random
practice and flailing.

In our age group, I suggest you look at 'open' or 'ladies'
style frames in a medium size. Given the season, you'll get
some attention in a bike shop and as the saying goes it
doesn't cost to look. A test ride or two will also be useful
I think.

Note a few points:
1. There are not many mixtes made now. Get over it. Open
frames may be aesthetically different:
http://www.yellowjersey.org/WFDJHZ.JPG
http://www.yellowjersey.org/wfdopna2.jpg
but your flexibility and limberness probably won't improve
with time.
2. I assume you're looking at upright handlebars rather than
road (drop) bars. The large offroad market means you can
get matching quality compatible shifters for most popular
road gear systems. Flat or upright bars do not mean a lower
quality bike.
http://www.yellowjersey.org/nirofla2.jpg
3. Sporty looking bikes for younger people have low straight
handlebars. It's quick and cheap to add some height with a
handlebar swap. Bonus- riser bars adjust fore and aft with
an allen key in seconds.
4. If you have higher closer handlebars, more of your weight
shifts back, onto the saddle. Generally a wider saddle is
indicated AEBE.


And a shorter top tube. But I like the longer top tube because it keeps my size twelves out of the spokes. With a pair of North Road Bars (the Uno-Kalloy brand has served me well) and an adjustable stem you can adjust the height of the grips as well as your reach to the grips for the more upright position sensibly advised above, without sacrificing the desired wheelbase. -- AJ

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

  #16  
Old October 12th 19, 09:14 PM posted to rec.bicycles.tech
Tom Kunich[_5_]
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Posts: 908
Default Beginner question

On Friday, October 11, 2019 at 8:31:13 PM UTC-7, Joy Beeson wrote:
On Sat, 12 Oct 2019 06:22:13 +0700, John B.
wrote:


Most of the formula use height and in-seam measurements use . Try
https://www.bicycle-guider.com/bike-...ke-size-chart/ and
compare it with your current bike, but beware that this fits you to
the bicycle, i.e., essentially the distance from the seat to the pedal
at the bottom of its stroke and if your problem is getting from the
ground to the top of the thing you will need to change these
measurements. But beware that the closer the seat is to the ground the
shorter the distance from the seat to the pedal will be and you may
find yourself pedaling with bent knees which can be uncomfortable as
well as inefficient.


Seat height is easly adjusted; it concerns me more that a shorter seat
tube implies a shorter top tube, and I'm perfectly happy once I get
aboard.

A mixte of the same height would be perfect, but nowadays people think
that "mixte" is another way to spell "drop frame".

Which reminds me that I used to know a very heavy rider who had a
custom diamond-mixte -- it had both a top tube and a pair of mixte
stays, and the rack was part of the frame. He delighted in showing
that the rack would support his considerable weight.

("Know" in the sense of acquaintence of an acquaintence.)


Frames are measured from the center of the bottom bracket to the center of the seat cluster OR to the top of the top tube. That is C-C and C-T.

Saddle height is usually approximately 1.06% the inseam measurement but this can vary with your crank and foot length and how your ankle articulates. So you set it to this measurement as a starting point and if you have pain in the back of the knee you are slightly low and on the front of the knee, high. Do not go far from this measurement.
  #17  
Old Yesterday, 01:06 AM posted to rec.bicycles.tech
Joy Beeson
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Posts: 1,386
Default Beginner question

On Sat, 12 Oct 2019 08:28:07 -0500, AMuzi wrote:

2. I assume you're looking at upright handlebars rather than
road (drop) bars. The large offroad market means you can
get matching quality compatible shifters for most popular
road gear systems. Flat or upright bars do not mean a lower
quality bike.


The other way around. Upright bars aggravate my damaged rotator cuff.

Also, the last time I rode my upright-bar bike less than half a mile
to Sweet Dreams, I was out of breath when I got there. I don't even
notice that distance on my drop-bar bike.

--
Joy Beeson
joy beeson at comcast dot net
http://wlweather.net/PAGEJOY/

  #18  
Old Yesterday, 01:08 AM posted to rec.bicycles.tech
Joy Beeson
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Posts: 1,386
Default Beginner question

On Sat, 12 Oct 2019 03:09:17 -0700 (PDT), Andre Jute
wrote:

Joy, depending on how hilly your countryside is, if you're forced to buy a complete new bicycle because your components won't fit whatever you can get, you may also want to look at the RANS
http://www.ransbikes.com/bicycles/
on which Tom Sherman, who used to post here, was very keen. They're crank-forward (CF) designs, so not much chop in hilly country, but when I made up a few of my own designs in wood to test for suitability, the lot called geribikes for the obvious reason that I was getting on a bit and wanted a bike that I could step over easily, I found the crank forward by far the most suitable design not only for me (on the flat) but for every older person I tried it on. Unfortunately, my town is called the Rome of West Cork for the obvious reason and my countryside is up and down, no rideable flats, so I need to sit over the bottom bracket.


A few years ago, after I tracked snow into the kitchen and twisted my
knee, I bought a Trek Pure flatfoot. Great bike for cripples; I call
it my "pedal-powered wheelchair". I'm sure the knee healed faster
because I could exercise it without putting weight on it -- and I
continued going to places where I'd walked before getting hurt.

But I can't go any farther on it than I could walk ten years ago.

Well, I've never walked all the way to the hospital, and I did that
once on the Pure. But I used to walk farther than that without
leaving the village.

I have to get off and use the crosswalk at intersections because a
bike you can't stand up on is very slow off the mark, but it would be
good for people who ride on sidewalks, because it's easy to get off at
intersections, and you can "walk" without getting off when you are
waiting for a chance to overtake a pedestrian.

--
Joy Beeson
joy beeson at comcast dot net
http://wlweather.net/PAGEJOY/

  #19  
Old Yesterday, 01:12 PM posted to rec.bicycles.tech
Andre Jute[_2_]
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Posts: 9,319
Default Beginner question

I got your remarks about the CF Trek above, Joy. It's the reason I gave up the crank-forward style altogether: no way to lay down any power.

On Sunday, October 13, 2019 at 1:06:55 AM UTC+1, Joy Beeson wrote:
On Sat, 12 Oct 2019 08:28:07 -0500, AMuzi wrote:

2. I assume you're looking at upright handlebars rather than
road (drop) bars. The large offroad market means you can
get matching quality compatible shifters for most popular
road gear systems. Flat or upright bars do not mean a lower
quality bike.


The other way around. Upright bars aggravate my damaged rotator cuff.

Also, the last time I rode my upright-bar bike less than half a mile
to Sweet Dreams, I was out of breath when I got there. I don't even
notice that distance on my drop-bar bike.


This is a standard problem for people of a certain age, and even for lifelong cyclists who are merely middle-aged. Because I'm finicky about ergonomics around my hands, I'm a very big fan of North Road bars for their huge adjustability, but I came to cycling late in life, and already under the physio's care for fused bits in my backbone from years of sitting upright in hard chairs. (A problem I alleviated by designing and licensing an ergonomic chair for writers.*) So I sat almost upright on my bicycle from the beginning.

But I'm on another conference of bicycle tourers where many have been riding drop bars all their lives. Their bodies get set in a mode by years of practice and while some of them are willing to try flat bars and North Road bars, their bodies are just not happy, and frankly I see no point in forcing someone to change the habits of a lifetime in a hobby or a lifestyle choice if it will hurt physically or otherwise reduce the advantage they derive. (Some of the self-styled "bicycle fit specialists" in Ireland are a menace.) However, it is often possible to set drop bars a little higher, and to ride on the hoods more often, and so gradually raise the posture of the back to an angle more commensurate with the age of the skeleton even if not theoretically perfect. There have been reports of pleasing results by small changes, which is about all we can expect.

Andre Jute
Growing up with your bike

* When my prototype chair wore out, the new owners of the license reneged on a handshake deal made thirty or forty years ago to give me a new chair free of charge on request. So I switched to Herman Miller Mirra chairs and have been very happy with them. A good tip is to order all the options except the cloth cover, because the options contain the tailorability of the Mirra. A lot of people like HM's often less expensive Aeron but I find it a bit pompous for no particular advantage, and in subtle ways not quite as good as the less flashy Mirra.
 




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