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  1. #1
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    Where to learn about tubing choice?

    I can't seem to find much info on-line about tube selection. I've found some general info about differences between different materials, but nothing to the extent of how to actually decide on a tube set for a particular rider/frame design. Any suggestions on where I can learn more? In print?

  2. #2
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    google Reynolds tubing, columbus tubing, true temper tubing, etc., you'll find a lot.

    Brian

  3. #3
    Randomhead
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    are you thinking about building your first MTB frame? 9/6/9 is all you need to know for that. Build some more frames and you will start to have different ideas, but maybe not for mountain bike frames.

  4. #4
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    I created a handy online tool to help you pick tubing.

  5. #5
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    you should have one that alternatese between 9/6/9 "but it's for a road bike" 7/4/7 "but it's for a mountain bike "9/6/9"

  6. #6
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    Where to learn about tubing choice?

    No comments about diameter?
    mtbtires.com
    The trouble with common sense is it is no longer common

  7. #7
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    I am a few frames past my first frame and would like to learn more. Starting with just basic stuff like tube diameter/thickness in relation to rider weight/size. For example while 9/6/9 might be a reasonable rule of thumb, what if the guy/girls is 250 lbs and 6 foot 4, or on the other end 95 lbs and 5 foot 2? I have some general appreciation that the big guy needs larger diameter tubes with thicker walls, but I haven't been able to find any more specific guidelines. Seems like this kind of info must be available? I do see that in the PDF from columbus there are some suggested combinations for either road or MTB, but it's not very detailed.

  8. #8
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    Quote Originally Posted by rpiontek View Post
    I am a few frames past my first frame and would like to learn more. Starting with just basic stuff like tube diameter/thickness in relation to rider weight/size. For example while 9/6/9 might be a reasonable rule of thumb, what if the guy/girls is 250 lbs and 6 foot 4, or on the other end 95 lbs and 5 foot 2? I have some general appreciation that the big guy needs larger diameter tubes with thicker walls, but I haven't been able to find any more specific guidelines. Seems like this kind of info must be available? I do see that in the PDF from columbus there are some suggested combinations for either road or MTB, but it's not very detailed.
    On the Henry James site in their pdf for ordering tubing, there is a chart at the end that has recommendations for "kits" based on the type of bike you want and rider weight range. It is for True Temper tubing specificially, but it's a good place to start.

  9. #9
    Plays with tools
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    snake oil makes tubing so much stronger!

  10. #10
    Who turned out the lights
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    Quote Originally Posted by dr.welby View Post
    I created a handy online tool to help you pick tubing.
    PVD says it suck, try again! Classic.

  11. #11
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    Quote Originally Posted by rpiontek View Post
    I can't seem to find much info on-line about tube selection. I've found some general info about differences between different materials, but nothing to the extent of how to actually decide on a tube set for a particular rider/frame design. Any suggestions on where I can learn more? In print?
    You are getting a bit of a ribbing for asking this Question. This is actually a very fair question.

    A bit of history. From the time the safety cycle became the design of choice, frames have been made using 1" Toptube, 1 1/8" Downtube and Seattube. It WAS the industry standard until the 1980's. Then the tube Dia's where upped to OS, this better suited the growing MTB demands for stronger frames due to the nature of off road riding. Then came XOS, larger again.

    If you use the 'old style' as a reference as a starting point for the minimum you need to use (there is history to support this) then any diameter tube that is larger will give a stronger frame.

    Bikes have diversified now to such an extent that using a formula that simply gives you what you want to use is really not possible. This is where you surf the Net and look at anything that moves to get an idea of what builders are using and being observant of bikes you see in real life around you to guide you.

    The True Temper site has the only chart that gives any form of guide.

    If at this point, you have only purchased 'Tube-sets', the step up for you is to mix and match tubes to various characteristics that you are looking for in a frame in its intended performance parameters. This takes time and experimentation, and does challenge the grey matter.

    As a starting point, you will not go wrong if you use the strong DT through to rear dropout route. Seat tube and Top tube Dia's are not so critical when starting out.

    Eric
    BRAKES...? I'm trying to go FASTER!!!

  12. #12
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    the reason he took some ribbing is that it is a very, very broad subject. And the direct answer to his question is that there is no single source of information. The primary interest of a framebuilder is that the tube should not be so weak as to break. After that, it starts to be a matter of taste. I happen to think that the most ridiculous thing about bicycles is weight weenie-ism as applied to frames, particularly steel frames. But a lot of people are starting to think they like more flexible frames, and that's harder to argue with.

    The only thing I can add for the OP is that don't discount the use of straight gauge 4130 for large/tall riders. And you can go with thinner tubes for smaller bikes, but don't forget small/light riders can ride a bike hard too.

  13. #13
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    Tubing choice? This is where you, the custom framebuilder, come into the equation. It's up to you to decide the material, diameter and wall thickness to achieve the strength and ride qualities you (or your customer) is looking for. Yes, True Temper offers a chart as a guideline, but what's the fun in that? Engage your brain, take chances, be a designer, for crying out loud!

  14. #14
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    Just go big or go home. Just use the fattest tubes you can get.

    Uber Oversize for road frame.

    42mm downtubes for mtb.

  15. #15
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    Quote Originally Posted by golden boy View Post
    Tubing choice? This is where you, the custom framebuilder, come into the equation. It's up to you to decide the material, diameter and wall thickness to achieve the strength and ride qualities you (or your customer) is looking for. Yes, True Temper offers a chart as a guideline, but what's the fun in that? Engage your brain, take chances, be a designer, for crying out loud!
    If I am understanding the OP correctly, he has built a frame/frames. He is wanting to branch out and spec frames of varying sizes and is finding it hard to get the relevant information to achieve that task. It can be a daunting task to understand all the information and achieve an acceptable choice and meet customers expectations with little info to work with. This is a transition period for him and a considerable step up from just producing a frame for his own use.

    There is no magic bullet here. Any option becomes an experiment and adventure.

    It does cost to play around and develop optimal combinations of tube mixes - tube, weld materials, freight, machining if needed, some form of coating etc. For me in New Zealand, that price is NZ$800. Not to be lightly considered. This why I think this is a very relevant question that he has raised and should be of interest to us all really.

    Possibly, it may be more helpful to the OP if you were to describe the design brief and put it 'out there' and see what responses you get. Being specific will zero in on that "type" and add to your knowledge base. Despite the ribbing, it focuses the brilliant minds here to serious answers, thought and consideration. Use only experienced builders info.

    Happy Hunting

    Eric
    BRAKES...? I'm trying to go FASTER!!!

  16. #16
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    Ok, thanks very much for all the responses. I appreciate it. I just thought there would be more info out there somewhere but I guess not. I will take a look at the Henry James PDF and go from there, and maybe post some designs for comments.

  17. #17
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    Quote Originally Posted by dr.welby View Post
    I created a handy online tool to help you pick tubing.
    Dr Welby, I thought the 'tool' was brilliant....lol

    Eric
    BRAKES...? I'm trying to go FASTER!!!

  18. #18
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    one thing that starts to limit the choices for most of us is available tube lengths. Can sometimes get frustrating.

  19. #19
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    I mentioned about becoming aware of what is being made by others around us to give us a cue as to what is being used. This has a few flaws, such as how do you know where butts are on a tube of a bike when you have an an evenly rounded tube and don't have X-ray vision?

    Prior to this wonderful information source of the inter-net, living in the most outer-most place in the world, and having only links to a supplier here in New Zealand who imported Reynolds 531 tubesets in old school 1" & 1 1/8" sizing, I had a customer who wanted me to copy his Columbus SL tubed road frame. I knew that this would be difficult, not that I could not copy it, but that it would 'feel' different. I had previously cleaned tubes and measured the Reynolds butt lengths, internal taper sections and centre sections. (No print info was known to me) and I knew Columbus would not be the same. Out came a tuning fork, and tapping the tubes and using a non-permanent marker pen, established where the butts were and was able to compare the differences.

    At this point, would the 2 frames be the same? Contacted the client, we discussed the variations first hand with pen marks on every thing so he knew I could not replicate his beloved bike and proceeded with the 531 build. Interesing outcome was that the 531 was heavier (expected that, not by much though) but also stiffer as the Reynolds that I was using at that time had short centre sections which equals a stiffer tube. He did like his build and we learned alot. 2 frames externally indentical, different personalities.

    Such was the old day's, and it was a simple task then. We discuss so much about Geometry, Robot welds, Jigs etc, but I believe the real science is in the structural engineering of which tube selection is a complete mystery, especially for those who are now entering this wonderful world of frame building.

    It would be wonderful if those Design Engineer types could unravel some of the science behind this subject so those now coming into this field of the bike frame can resource and get their heads around these challenges.

    Eric
    BRAKES...? I'm trying to go FASTER!!!

  20. #20
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    Quote Originally Posted by rpiontek View Post
    I can't seem to find much info on-line about tube selection. I've found some general info about differences between different materials, but nothing to the extent of how to actually decide on a tube set for a particular rider/frame design. Any suggestions on where I can learn more? In print?
    Have a look on this site: Easycalculation.com/engineering calculations/mechanical engineering/deflection of round tube beams.

    Don't try to use the figures for anything other than understanding the correlation between tube diameters and wall thicknesses. I understand that this subject can get as murky as thick mud, and I prefer to eat pie rather than calculate using pi, but this calculator does shorten the heavy maths involved. I made up a 1 page chart for myself to compare. Eg: DownTube: a 26" x 1 1/8" x 0.028 wall using 10lb force vrs 1 1/4" x 0.020 gives the same deflection, but the thicker 1 1/8" has slightly better bending stress. In a frame, if you could build one this way, the 'feel' would be similar. I would use the larger dia, as it is lighter in weight.

    However, we don't tend to build this way as many builders will use Double-butted tubes, and boy, does this get the head spinning!!!!!

    If I compare True Tempers Hoxgold-DT3 tube to Columbus Zonm12650 31.7mm downtubes, the TT .7/.45/.7 x 650mm vrs Col .7/.5/.7 x 650mm have differing Butt sections of 102/51/345/51/102 for TT and 40/40/430/40/100 for Col. The 'feel'given by the TT will be stiffer than the Columbus due to the shorter centre section/longer Butt at the head tube over the Columbus tube. The calculator cannot give you the answer, and there are just a huge number of options/combinations if you really look hard and mix and match between tubing providers. The Deflection as used in a frame is limited in its use as a frame does not really experience this sort of loading except at brake location points. A frame under riding stress has pedal inputs and shock loads as bumps are encountered, this why I suggest using this info comparitively only.

    Hope this will help you a little.

    Eric
    BRAKES...? I'm trying to go FASTER!!!

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