Conference noted::bicycle

    I'm also trying to design a touring bike.  It'll have water
    bottle brazons everywhere and plenty of fender clearance.
    (and of course serial number 1).

    This my general impression regarding tolerances on bikes:
        Top Tubes +/- 1 inch
        Seat Tube +.5/ -1.5 inch
        Seat Angle +/- 1 degree (doesn't matter that much)
        Head Angle +/1 .3 degree (quite important.  You pretty much want
            it to match your forkrake and desired handling.)

    This my impression. would someone who has riden lots of
    different bikes care to comment?


    I'm not sure how old the talbot's book is.  There has been a
    trend in the past 15 years towards steeper angles.

    Is going to be a steel frame or aluminum frame?

    If you are going to use steel and lugs, then you have a smaller
    choice of tube angles.  If it's a welded frame (steel or Al)
    then you can make it anything you like.

    How does Talbot's go about the design?  I've heard of some
    design styles figure the main triangles first using available lugs,
    and then absorb all of the stability concerns into picking
    the right kind of fork.

    A couple of years ago I took the aluminum bike course at MIT.
    Their method was to pick the fork first, and then design back from
    that.  I still have my handouts from the course.  If you live in
    eastern Mass, I might be able to lend them in exchange
    for a look at your sources.

    Has anyone ever done any dynamic modelling of bicycle stability?

    -Jeff Bell

    	I already answered the author directly, but I thought I would
    run on about Talbot's suggestions here as well.  He relys on the
    old Italian CONI manual.  It was written by people who raced over
    incredibly poor surfaces at distances much longer than pros use
    today.  As a result, the frame design guidelines really emphasize
    comfort at the expense of handling & putting power right into the
    back wheel.  Look at the chainstays and forks on a 20 year old bike,
    and you'll see what I mean.
    
    					John

    There are 7 critical dimensions that must be thought out before
    building the frame, they are:
    
    	o Seat tube
    	o Top tube
    	o Fork Rake
    	o Seatstay length
    	o BB Height
    	o Head tube angle
    	o Seat tube angle
    
    Taking each of these, fill in those numbers that are easiest:
    
    o Seat tube, if you have been riding for some time, you probably are
      real close to what if comfortable.  
    
    o Seat tube angle, in both frames I built (one racing, one touring)
      I used the same angle on each, 73.3 degrees. This put my knee over
    the pedal at the proper point.
    
    o BB Height - On my touring bike I have a very low BB (10.25") to
    give better stability.  I don't tend to pedal into corners on this
    bike so may as well get the stability advantage when loaded with
    panniers
    
    o Chainstay length:  A lot of opinions here, but based on successful
    builders, I feel for an average size touring frame 16 3/4 to 17" is
    appropriate.  You can stiffen the triangle up by using larger seatstays
    and/or heavier tubing.  My wife has a Bruce Gordon touring frame with
    17" Columbus SP stays and it is real stiff.  
    
    I was taught that the head tube angle and fork rake should mantain
    a balance.  As you decrease the headtube, you should increase the
    fork rake to have proper trail.  From what I remember the numbers were:
     72 degree angle = 2 1\8" fork rake
     73   "      "   = 1 3\4
     74              = 1 1\4
    
    I used a 72 degree angle on the touring bike to give good stability.
    
    What materials are you using, silver soldering?  How about the jig?
    
    (Watch those investment cast BB, they can really suck up the heat
    when brazing)
    
    Good luck, it is worth the effort.
    
    steve	

    Actually, the very latest trend for road bikes is back to 
    shallower angles; say, 73.5 parallel.  Bikes like my Sannino
    (74.5 parallel) have gone out of fashion recently.
    
    MATT

    	The recent relaxation in trendy angles is a moderate adjustment 
    compared to the change in angles, fork rakes and wheel base from 20
    years back.  I read an article about ANOTHER trend in frames for
    hemanathons.  (Just when it was hip to have a reasonable bike, too...)
    Some builders are cranking the seat angles WAY up to optimize position
    using tri-bars.   It makes them sit in an out-of-the-saddle sort
    of position that looks unstable to me.   It is a pretty special
    application - I wouldn't want to descend on one.  None of this stuff 
    helps our up and coming designer, but it is fun to rant about.
    
    					John

      Thanks for all the replies so far.  They are certainly adding some
      fuel to the fire or angles to the bicycle or confusion to the neo-
      phyte designer.  I'm sure that out of it all will come enough info
      for me to procede with some tentative degree of confidence.  Let
      me try to answer the questions that were posed in the replies to
      my base note.

  .1   * The Talbot book was first copyright in 1979 and again in 1984.

       * For this my first attempt I will most likely use steel.  I want
         to get some experience in frame building and evaluate the design.
         What I really want to do is build it from titanium, but not first
         time 'round. 

       * Talbot uses available lugs and figures the main triangles first.
         If I remember correctly he says that by using pressed steel lugs
         there is the ability to change angles over small increments with
         out too much trouble. Then he goes about designing the fork using
         a nomograph which relates head tube angle, rake dimension and
         steering characteristics (oversteer/understeer, quick/touring/neu-
         tral). He states that much of his work is based on the old Italian
         CONI manual (.2 mentions this also). 

       * Thanks for impressions on tolerances.  Any one else care to add
         their twopenceworth to this one?

  .2   * John mentions here that the old CONI guidelines emphasize
         comfort and long distances over poor surfaces at the expense
         of handling and putting power into the back wheel.  Herein
         lies my chief problem.  For an older chap like myself, comfort
         is a major consideration.  Also, in order to achieve longer
         distances without overstressing the ageing physique, it is
         important to put as much power to the road as possible.  The
         design must balance these two opposing requirements.  I also
         like good handling machines whether it be bicycles or sports
         cars or musical instruments. This is what the research and
         planning is all about, and I'm still confused!

  .3   * Steve, your B.B. height is low compared to anything I have
         ridden within recent memory. It seemt to be more in line
         with what the Merlins and Serottas and perhaps lots of the
         other more modern bikes use. You say it is chosen to achieve
         greater stability. Does it, and do you care to give words to
         some subjective impressions of what the difference in feel is
         over say an 11 or 12 inch B.B. height?

       * On the head tube angles and fork rake you quoted, I checked
         them against the nomograph in Talbot.  The 72 degree angle
         with the 2 1/8" rake falls right on the neutral steering
         line. IMHO this is where you picked up the major part of
         the stability you were looking for. The 73 deg angle and
         1 3/4" rake falls just about on the "Touring" line.  The
         74 deg angle and 1 1/4" rake is almost to the quick or
         oversteer line. Nobody in this discussion has yet said
         anything about what the desireable trail dimensions are.
         You mention that one must have proper trail, but we don't
         know yet what proper trail is.

       * I will be silver soldering assuming the final design comes
         out using lugs.

       * I'm very pleased to see that you think the results are worth
         the effort.

  .4 and .5   

       * Thanks for your inputs on angles. I get the feeling that
         perhaps the old CONI guidelines may not be very far off
         mark.

    I guess I am going to have to find places to ride some machines
    where the owners or sellers or whatever also have some of the
    technical design data available as well so I can get some of the
    real feel of some of these variations. More discussion is still 
    welcomed.  We haven't got this thing anywhere near sorted out yet.
             
    Bill      
              
            
           

    An 11 to 12" BB is real high.  I believe Criterium machines are
    close to 11.  The 10 1/4 is based on tubulars, naturally it will
    increase with touring clinchers.  The difference, I am not sure,
    all I can say that with panniers the bike was very comfortable
    going down the Canadian Rockies.  Unless you dive through
    corners, why not give is a shot, it certainly won't hurt.
    If you require about a 58 cm frame and live in the MA area, 
    you are welcome to give it a try.
    
    I don't recommend using cheap, rolled and welded lugs.  Investment
    cast lugs will save hours of filing and be far easier to braze.  They
    are designed to give you the proper gap to optimize silver's strength.
    If you gap silver too much, it loses all its strength.
    
    good luck
    
    steve

      >>>What I really want to do is build it from titanium, but not first
      >>>time 'round. 
         
    Bill,      
	I think you'll find out that titanium is out of the question. If not
due to the price, then due to the fact that it requires special tools and
environment in which it needs to be worked with in welding or soldering..???
I read that the material is only available to licensed shops that know how to
work with this metal. This might be a ploy to keep Merlin Metal Works in
business though. Check it out...

TD               
            
           

    	The balance that you are describing sounds like it lies somewhere
    around a DeRosa or Peter Mooney.    They handle well, but aren't
    terribly rude.  If the Serotta that you have measurements for is
    not one of their criterium bikes, that might do it as well.

    Re .9    No objections whatsoever to plagiarizing a master.  Only
    question is which master and which masterwork.  Once we have those
    answers, how do we get the numbers?  The Serotta is the Colorado II
    and I have the basic dimensions for the 56 and the 64 cm frames.
    They come from the July 89 issue of Bicycle Guide along with several
    other bikes.  I'm pleased and surprised that we have gotten this far
    with the notes discussion, especially where I haven't really said
    anything about my own dimensions yet. Age - I'll never see 60 again
    Height - 6'1"  Weight at present 168 but I have to loose about 10  lbs
    inseam - 33".  My legs are a little long for my torso as are my arms
    but less so. I have rather thin bones and tend to carry most of my
    weight around the middle. So, with that disgusting picture before
    us,  my good readers, perhaps we can begin to put this picture into
    a more real perspective.
    
    Bill

    RE: .10
    
    What I like about your approach as a first-time frame-builder is that
    you're researching the topic, and not blindly plagiarizing a master.
    That way, you begin to develop and execute your own principles of 
    design.  Since you're not doing it in ignorance of the masters'
    work, you're bound to come up with at least decent results;
    more importantly, as you discover things on your own, you 
    might end up becoming something of a "master" yourself!
    
    
    MATT

    (bet I catch some flack on this one)

    A diamond frame bike is a diamond frame bike. If you want comfort,
    build a recumbent.  I'd suggest a long wheelbase, low handlebar, round
    steel tube design similar to Avatar, DeFelice. Mount the bottom bracket
    as high as possible to get the best spine-to-femur angle. Use 20"
    front, 27" rear wheels. Pay the most attention to seat design - the
    front edge is very important - note the 'saddle horn' support on the
    Avatar. If you ride in hills, plan a triple crankset from the
    beginning. (Hilly terrain is the only excuse not to go recumbent [other
    than a reluctance to be different/a leader].) - Chris
    	

    RE: .-1 "Hilly terrain is the only excuse not to go recumbent..."
    
    Well, ok, here's some flak.  I believe there's a lot of discussion
    about other disadvantages to recumbents.  Chief among these is
    ability to see and be seen in motor traffic. I don't think that's a nit.
    
    Another is comfort.  The diamond-frame's "natural shock absorbers"
    (human limbs) don't apply to a recumbent.
    
    But maybe our frame builder would be interested in a recumbent just
    for the fun of it...
    
    -john

      Sorry John,  the see and be seen 'problem' is mostly a figment of
    people's imagination (but not a cute as Figment at Epcot).  The typical
    bicycle-car accident happens at intersections. When I'm on my diamond
    frame, it seems like people see me, look for other traffic, forget me,
    and turn/pull out/whatever.  On my recumbent, THEY DO NOT FORGET ME. If
    anything, they forget to drive and get into car-car problems. When
    recumbents become more popular/normal this advantage will cease, but it
    looks like that will be a long time from now the way cyclist's react to
    recumbents.  
    	Only a couple of percent of car-bicycle accidents happen when the
    recumbent's lower height is a factor: the cresting a hill case. If this
    bothers you, you can use a flag. Visibility from the bike is similar to
    diamond frames on the open road, but does suffer a bit in heavy traffic
    (you aren't high enough to look Over most cars).
    	On a recumbent, you can raise your tail off the seat by arching
    your back, being supported by your shoulder blade area and your feet.
    This results in a very similar effect to standing up on a diamond frame
    (crossing RR tracks, etc).  The comfort of not having a skinny seat
    pulverizing the material between it and your pelvis is the main comfort
    advantage.  Those with tough tails will probably want to stay with the
    traditional, cheaper, (less safe, less aerodynamic) bicycles. - Chris

    Ok, those are good answers.  It is true, motorist seem to have X-ray
    vision looking through cyclists.  My main fear is not being able to
    see around things as much.  Of course, as a short person, I go for
    height wherever I can.  :-)
    
    As to the cushioning effects, it sounds reasonable, but I'd have to
    try this to be convinced.
    
    By the way, cresting a hill is bad no matter what kind of frame you're
    on... 
    
    cheers,
    -john

    I haven't seen a copy but I saw a recommendation for a manual by
    Paterek that was in a recent bike mag.  I think it was 446 pages or
    so about frame building.  It would give you another perspective on
    the task.  I can look up the information if you are interested.
    Others might have seen it already.

I'm really envious.  There was an ad in the UK comic from I think Harry Quinn,
 offering a week's holiday in Wales learning about frame-building and you got
to build and take away your own at the end.

Sounds a great solution to me, but can you afford the holiday in UK ???

    This is turning into a really good topic.  Having almost as much fun
    reading it as actually doing something.  That will come later. Glad
    you folks have the positive feelings and confidence inspiring comments
    you do.  It is making me much more motivated to go through with it.
    
    Re .12 and .13, I've always been fascinated by recumbents ever since
    my first sight of one on the road.  Must confess that the see and be
    seen problem is the one thing that might keep me from building one.
    Perhaps one of these days I will try to find one to test.   
    
    .17, Would love to take a frame building holiday in the UK.  Wife is
    not a cyclist (can't/won't even ride one) and since we lived in
    Ireland for three years and both love Ireland and the UK, no way is
    she going to let me go off on such a holiday. We both have too much
    over there to be involved with. Oh Woe!
    
    Bill

Matt, I appreciated your report on the European trade show.  Well done.
Am posting this reply here as it deals most specifically with the frame
building base note of mine. In your description of the frame by Cinelli
you state that "the steering tube ends below the top of the top tube, 
so that the steering stem points forward at exactly the same level and
angle as the gracefully reclining top tube".

This configuration and your enthusiasm for it caused me to try sketching
it out for possible incorporation in my design.  I am puzzled a bit by
the problem of attaching the top tube to the steering tube if the steer-
ing tube ends below the level of the top of the top tube.  Is this a 
lugged design? Is there some sort of angle bracket between the steering
tube and the top tube for support (sort of like the corbells in Medieval
stone work)?  My initial reaction is that this is going to be a very weak
point in the structure.  Please shed some more light on this one.

Bill       

    I had the same problem when I tried to sketch it out for someone
    this morning.  Three factors combine to make this work:
    
    1. There's some overlap between where the steering tube stops and
       where the top tube begins.
    
    2. The junction between the two tubes is built up into a curve
       (no lugs), giving more contact area.
    
    3. Some metal wraps around both sides of the stem from the top
       of the top tube to the end of the steering tube.  This keeps
       the handlebars from being turned more than about 70 degrees
       to either side, but it shouldn't hurt normal steering.
    
    I've tried to draw it below, using the limited capabilities of the
    terminal. (The reclining top tube is lost....) This is still probably
    not the stiffest bike in the world, but I bet it's adequate.  
    
    
    ----------  -----------------------------
       Stem   |////////// Top Tube
    ------|  ///////////
          --////////////
        ---/////////////
        |///////////--------------------------------
        |//////////
        |Steering/
        |Tube    |

    As a result of all this I am somewhat closer to being able to make
    some decisions. Close but not quite yet.  One of the next things
    to worry about is a source(s) of supply for materials (tubes, lugs,
    stems, etc).  I know just about any GOOD bike shop can supply the
    critical accessories such as brakes, cranks, pedals, headsets, etc.
    I expect that some of my decisions will be based on what is available
    for tubing and lugs. Are there any companies that issue catalogues
    listing frame materials?  I have located one, Quality Bicycle Products
    in Minneapolis.  The big catch there is that it is truly a wholesale
    to the trade only firm.  They will be sending out their new catalogue
    in December.  To get it you must supply your firm name and tax number.
    I imagine they would like to get it on company stationary as well.
    There must be some others that are not quite so fussy as to whom they
    sell.  WHO please?
    
    Bill 

I haven't seen their catalog in years, though.

MATT

    Talk to a local builder, ie: Wheel Works (Peter Mooney).
    
    There are also some bike shops that do frame repair such as
    Laughing Alley that must have access to this stuff.
    
    Does anyone know if a company named Proteus Design is still in
    business?  That is where I purchased my stuff 10 years ago.
    
    steve

>    Does anyone know if a company named Proteus Design is still in
>    business?  That is where I purchased my stuff 10 years ago.
    
If it's the same Proteus I used to visit a lot, they'd be in College Park 
Maryland ... a call to info (area code 301) oughta do it....

                                               ken

... and while you're calling Maryland, you might also try Alpine 
Bicycles in Rockville, MD. I'm still riding one of Ned & Fred's 
frames.....
                                   ken

    	Peter Mooney sold me some tubing and lugs, so I know that you
    can get them there.  There is also Nova Cycle supply, Proteus, Security
    Bicycle, Euro-Asia, and lots of others.   The main benefit to being
    a business is that you pay a lot less.  I didn't bother.  You can
    still get most everything except Reynolds 753 if you try hard enough.  
    
    	I found that if you get on Peter's good side and get him when
    is isn't busy, he will critique your lug work and offer some advice.
    It helps if you buy your supplies from him.  His jigs are pretty
    interesting, too.  He took a metal class at a local vo-tech school
    just to get access to the equipment that he needed to build his
    tooling with.

    Are there any standards about rear derailleur placement?

    I imagine that most derailleurs expect to be a certain
    distance back from the axle.  I could measure it, but
    those dropout adjustment screws allow a range.

    There's also a certain distance sideways from the
    plane of the locknut. This is probably a byproduct of
    dropout thickness.

    Anybody know where I could look it up?

    -Jeff Bell

re           <<< Note 1372.27 by TALLIS::JBELL "Zeno was almost here" >>>
>                          -< rear dropout standards >-

>    Are there any standards about rear derailleur placement?

>    I imagine that most derailleurs expect to be a certain
>    distance back from the axle.  I could measure it, but
>    those dropout adjustment screws allow a range.

	Well, its kinda fixed relative to the frame, i.e. its just a 
function of the dropout thats used.  If you're worried about where it 
hangs relative to the axle (relative to the CLUSTER might be more 
appropriate) ???  I think the answer is,  "adjust the drop out screws 
to get the axle centre line aligned with the seat stay and chain stay 
centre lines".  Or are you asking about dimensions to help you select
right rear drop outs ?   Either way, you probably won't find much
choice available. 

>    There's also a certain distance sideways from the
>    plane of the locknut. This is probably a byproduct of
>    dropout thickness.

	I think the outside face of the dropout is the reference face, 
everything  "works"  from there.  Variation in dropout(hanger) 
thickness is well within the adjustment range of most derailleurs.

>    Anybody know where I could look it up?

	I don't, but most of this stuff is intuitive once you sketch 
it out...........  errr, I'm making assumptions again (-:


	Reg

>	Well, its kinda fixed relative to the frame, i.e. its just a 
>function of the dropout thats used.

    The problem is that I'm designing the dropout.  It will be cut
    from 1/4 inch aluminum stock.  I've got an n-th generation
    photocopy of the outline, but I'd like to check it.

    I suppose that I could measure those peices that come with a
    derailleur in case you don't have a derailleur tab.  It would
    at least give me what one manufacturer expected.

    -Jeff Bell

re           <<< Note 1372.29 by TALLIS::JBELL "Zeno was almost here" >>>
>                     -< Ahhhh, but who makes the dropout >-

>    The problem is that I'm designing the dropout.  It will be cut
>    from 1/4 inch aluminum stock.  I've got an n-th generation
>    photocopy of the outline, but I'd like to check it.

	I have a couple hanging around that I could drop off (pun), or 
since you seem to be doing an alumin frame, you could trace around the 
near vertical drop out/hanger of my Vitus frame.

	Reg	{currently in BXB, just down the road a little from 
		you}

>	I have a couple hanging around that I could drop off (pun), or 
>since you seem to be doing an alumin frame, you could trace around the 
>near vertical drop out/hanger of my Vitus frame.

    I had been planning to use a non-vertical dropout (the normal kind),
    since this was going to be a touring bike with plenty of
    room behind the bottom bracket.

    Does anyone know of a good reason not to use a vertical dropout?

    I understand that they were invented so that racing bikes could
    have really short wheelbases.  Is there any reason not to use them
    all the time?

    -Jeff

re           <<< Note 1372.31 by TALLIS::JBELL "Zeno was almost here" >>>
>                            -< Vertical dropouts? >-

>    Does anyone know of a good reason not to use a vertical dropout?

	I can't think of one off-hand...

>    I understand that they were invented so that racing bikes could
>    have really short wheelbases.  Is there any reason not to use them
>    all the time?

	Yes, I think that was so - plus they found that the adjustment 
range of a horizontal/diagonal dropout isn't really used very much.

	I'd guess that the  "horizontal/diagonal"  drop out was 
developed in the pre derailleur gear days (~ '50s ?) so that chain
slack could be adjusted, just a guess.  Of course, you might have
difficulty figuring out where the hanger boss goes if you try to
design a very upright dropout.  Unless you're going to mount fenders
there's probably nothing "wrong" with designing your own track ends
with a hanger boss on - {could look  REAL COOL (-:, (-:} to make wheel
removal easier. 

	Reg

Strength and frame alignment are issues in the direction of a drop-out.

A vertical drop-out has to have a frame in alignment.  The regular, sloping
down and to the front, drop-out can be adjusted for a slightly out of alignment
frame like if you crash a touring bike with 100 pounds of camping gear on it and
help is 50 miles down the road.

Klein went to a rear-entry drop-out on this year's off-road racing frames to
strengthen the hanger area.  But then off-road bikes are expected to take a
beating.  Cannondale has had enough frames returned due to hangers breaking
that they now bolt the hanger on.  You might want to look at the new Cannondale
and do it that way.