Talk:Bicycle frame

Aluminum vs Steel debate
I've removed some inaccurate references to this ongoing bicycle techie arguement from the Steel section. There are a lot of subtle references to this debate in the steel section (I've removed it) it said that steel was old fashioned, heavy and cheap. There is some of this in the Aluminum section where is talks about Aluminum being "generally agreed" to be heavier. There is also a lot of emphasis on Aluminum fatigue which is probably from people taking a pro-steel perspective. And all the stuff about frame flex doesn't look NPOV. Anyway, perhaps we should have something that objectively describes that there is debate about the benefits of each material... Though this would have to be done at the same time as removing the excessive sideways references to the debate that are all over the place elsewhere in the article. Also it's really only a Sports biking argument as the vast majority of utility and commuting bike are steel, all other materials are unusual with some pluses and minuses to them.

Frankly, after cleaning all that up, I'd like to see more in depth steel discussion of the types of steel and properties. I've added mention of 4130 steel which is very common, at least on the bikes here in Canada.

Perhaps we should make this article more managable by ***MAJOR PROPOSAL*** cleaving off the materials discussion into it's own seperate bike frame materials section? I actually stumbled upon (and then got caught up editing) this article trying to find a nice list of various types of tubing in both steel and aluminum bicycles. I'm trying to research tubes. But really this information isn't here at all but a materials article could include it, have space for encompassing material debates, and not bog down the whole notion of what a frame is in the main article. Rusl (talk) 05:02, 23 September 2008 (UTC)

Image added to frame size section
I added the diagram of common bicycle measurements because these are terms that abound bikeswaps and ebay's bikes for sale, etc. I hope that this is not seen as redundant as the other diagram addresses actual parts and this one addresses accurate measurements. --Circlemaker 06:16, 04 July 2006 (UTC)

Tone of Aluminum section
The forth paragraph of aluminum section needs work. Although I largely agree with the opinion of the author regarding the aerodynamic effect verses structural compromise of non-round tubing, the "beware" statements are not appropriate for wikipedia. I think this statement of such a controversial nature certainly needs a source if anyone can think of one. Bdentremont (talk) 05:34, 28 July 2008 (UTC)


 * I have placed a "inappropriate tone" template on it.


 * Frankly, I believe that the entire section on the weakness and failure properties of radically hydroformed Aluminum tubing are completely bullshit and have absolutely zero technical basis - you don't have to look very far or delve heavily into the engineering analysis (which has obviously not been done by the author of this section) to find race winning, acclaimed framesets that use said types of tubing. Many of them also have varying thickness profiles in the tube cross section to mitigate any losses in cross sectional strength.
 * Panzerjager88 (talk)


 * I've rewritten the section, and hopefully people find it an improvement. I've taken alot of the detail out as it sounded like a how-to, was unreferenced, unnecessary and probably untrue.  I took the inappropriate template off, as it seems unnecessary now.  Really the section needs more work as it doesn't flow, but it's a step forward.  Input?  Keithonearth (talk) 06:51, 25 June 2009 (UTC)


 * Much better, I really do not like the general tone or construction of this entire article though - there is a ton of supposition floating around about stuff for which there is vast quantities of data and research availlable for verifying facts. I think it is very important to discuss hydroformed tubing for the alu section as this is one of the huge advantages of the material as well.  You've made an excellent start thought - many of the previous entries in this article sounded like they were written by a steel obsessed and ultra biased Luddite. ;)


 * Another thing to consider is that stiffness goes hand in hand with power transfer - you simply cannot optimize power transfer and comfort compliance at the same time so frames that are stiffer transfer power better (trope put out by manufacturers aside), acoustic tricks like polymer inserts in carbon frames can dampen some base vibration however.

Panzerjager88 (talk)

Minor edit of Aluminum section
I added the bit about alloying extends the fatigue life to many years. The original text made it sound like aluminum frames will just break on you. While this may happen, it usually takes quite a few years of intense riding. I still see Cannondale CAAD 3 frames on the road. Comatose51 02:45, 29 August 2005 (UTC)

Should bicycle frame construction be merged into this? --Christopherlin 02:48, 13 Nov 2004 (UTC)


 * Steel frames can and do fail on you after "many" years as well keep that in mind in any discussion. Panzerjager88

Merged in material from bicycle frame construction
Whew. That took a while.

Could anybody add in material about geometries (road vs. comfort vs. hybrid vs. mountain) or any historical information? --Christopherlin 06:24, 17 Nov 2004 (UTC)

Triangle vs. trapezoid
195.179.206.165 notes that the front/main "triangle" is technically not one, as the top and down tubes don't intersect. However, most references I've seen call it the triangle nonetheless. Thoughts? --Christopherlin 03:38, 24 Feb 2005 (UTC)


 * Triangle. --Kit transue 21:01, 10 Apr 2005 (UTC)


 * Triangle as well, if one is to go on what The UCI has to say, in rule 1.3.020, "the frame of the bicycle shall be of a traditional pattern, i.e. built around a main triangle." even though their later definition of the main triangle clearly leaves room from forming of a trapezoid. see http://www.uci.ch/imgArchive/Rules/1gene-E.pdf --Chinakow 05:51, 21 April 2006 (UTC)

frames vs. geometries?
Suggest the geometry discussion be moved more to the cycle types category, and it be made more clear that the various frame components talked about here (or scheduled to be moved into this article) are based on the tubing-constructed safety bicycle.

I guess it seems that the article presumes the only frame is a safety frame, despite efforts to make it more inclusive. --Kit transue 20:05, 25 Mar 2005 (UTC)


 * I'm all for being more inclusive. Feel free to add mentions of less common frame types. The safety bicycle is the predominant one today, of course, so it does get the most mention.


 * I noticed that you made an article for Mixtie, which is but briefly covered in the main article here. The main article size isn't too big right now. I think that things about geometry should stay here. Duplication/expansion within each cycle type article would be good.


 * The reason I put merge notices on the various tubes is because of the short length of those articles, with little room for expansion as individual articles. Going to clarify the focus of the article, similar to the end of the first paragraph of mountain biking in a sec. --Christopherlin 21:23, 25 Mar 2005 (UTC)


 * The tube argument makes lots of sense. Still in favor of putting detailed descriptions of the different frame types in the cycle types category; the mixtie is an example of why I think it's wise to have those elsewhere.  The mixtie isn't described here at all--yeah, it's got a lower standover height, but it achieves it in a way that puts less stress on the seat tube than the open frame described here.  I find those details interesting, but fear putting all them in would detract from the readability of this article.  --Kit transue 21:01, 10 Apr 2005 (UTC)

What do folks think about detailing the effects the geometry variables have on the performance/utility of the bike? Something like:

Bottom bracket height: determines clearance of pedals and center of gravity. High BB height for fixed gears and mountain bikes, lower BB for touring, road, etc.

Standover height: the distance between the top tube and ground. Lower for moutain bikes where you might need to step on uneven terrain, lower still for convenience mounting the bicycle (clothing, touring). Higher moves the frame elements further apart to make the frame stiffer.

Head tube angle: steep for livelier steering, shallow for self-centering. (surely there's something about camber somewhere.)

Wheelbase: long for touring to keep racks out of the way, move the CG forward, allow for more water bottles :-) Long to reduce pitching over uneven surfaces.  Short to increase responsiveness.

Suspension: heavier multi-link for controlling bob, lighter single pivot for long travel, simplicity, and weight, none for....

and so on, covering riding position and the like.

That would lay the groundwork for better understanding the cycle types.... --Kit transue 21:01, 10 Apr 2005 (UTC) I think this is a major subject that is very difficult to research on-line currently - partially due to so many conflicting opinions. In example: I would like to take exception to the current article's discussion of seat tube angle. It ignores the effect that changing seat tube angle has on the relationship of the riders leg bones and muscles to the pedals. Traditional road triangle racing, sports touring and nearly all "touring" bicycles have nearly identical head and seat tube angles seldom being more than one degree difference. My personal finding is that regardless of the seat tube angle of my (many) bicycles, I end up positioning the saddle at exactly the same position relative to the bottom bracket - sometimes requireing a seatpost with more or less "setback". Without some consideration of the ergonomics of the rider, a discussion of frame geometry is very incomplete. (vidjunkie) Vidjunkie (talk) 19:23, 21 April 2010 (UTC)

from seat stay
A Single seat stay refers to seat stays which merge onto one section before joining the front triangle of the bicycle, thus meeting at a single point. A dual seat stay refers to seat stays which meet the front triangle of the bicycle at two separate points, usually side-by-side.

Frame geometry specification
In addition to saddle height, reach, etc., what about bottom bracket height and wheelbase? I don't know if the latter is spec'd as axle-to-axle, tire contact-to-contact, or bottom bracket-to-axle. Perhaps someone more knowledgeable could fill in here if these are useful? --Kit transue 21:01, 10 Apr 2005 (UTC)

Focus on racing bicycles
I have some issues with the pictures used on this article. It seems to me that judging just by the photographs, road/racing bicycles are over-represented. Maybe use more Utiliy or MTB type bike photographs more, since the former vastly outnumber racing/road bikes, anywhere in the world except perhaps in North America. —The preceding unsigned comment was added by Chicbicyclist (talk • contribs).


 * Yeah, all the other types of bicycles and cycling are underrepresented. Perhaps you'd like to help out with what you know. --Christopherlin 02:58, 20 April 2006 (UTC)

Carbon fiber as "primary" non-metalic material
While I was unable to find a source that explicitely lists carbon fiber as the primary non-metallic material, I have listed three sources, including a page from the highly-regarded and often cited Sheldon Brown's web site, that compare frame materials. All three include carbon fiber as the only non-metallic material in their discussions. Another way to look it this would be to list all the major manufacturers that offer carbon fiber frames (Trek, Specialized, Giant, Orbea, Felt, Raleigh, Scwhinn, Look, Seven, even aluminum frame pioneer Cannondale) vs all the major manufacturers that offer frames of any other non-metallic material. If there are any sources that indicate that any other non-metallic material is commonly used, or even currently in production (other than beautifully hand-crafted wood and bamboo), I would love to see it. -AndrewDressel 14:46, 13 March 2007 (UTC)


 * Hello Andrew, I have taken a look at the most recent references you added to the article bicycle. The are excellent references for much of the material. Unfortunatelly, I coudn't find, out of the 3 links, anything that mentions "carbon fiber" is the most popular non-metalic frame. Of course it is an "increasingly popular frame material". I will change the word "primary" to "popular." Perhaps, you could also place your references at various appropriate locations throughout the paragraph since having them all at the begining doesn't seem as relevant. Thank you! --CyclePat 17:11, 13 March 2007 (UTC) Copied from User talk:AndrewDressel


 * Seems silly, but okay. There isn't a source verifying that the frame is the main component of a bicycle. There isn't a source confirming that the most common frame design is based on the safety bicycle. There isn't a source specifying that the rear brake cable is most commonly routed along mounts on the top tube. There isn't a source corroborating the claim that a more economical method of bicycle frame construction uses cylindrical steel tubing connected by TIG welding. Why you let these slide while questioning the preponderance of evidence supporting the claim that carbon fiber is the primary and most commonly used non-metallic frame material is beyond my understanding. Does this somehow strike you as original research? Do you have support for a counter claim? -AndrewDressel 17:29, 13 March 2007 (UTC)


 * Please take note that there is strict policy regarding inclusion of material. Wikipedia articles must be based on reliable sources. Instead of trying to find counter exemples to this rule you may wish to try improve the sections of the article which you highlighted as lacking proper citations. --CyclePat 06:02, 15 March 2007 (UTC) Copied from User talk:AndrewDressel


 * If there is some question about the reliability of the sources I cite, please tell me what it is. I believe there is no point in looking for citations for the examples I highlighted because the points are widely agreed upon and there is not likely to be any source that bothers confirming them. That is why I chose those examples. The same is true of the primacy of carbon fiber among non-metallic frame materials. Due to your objections, I'll leave this discussion here and let readers draw their own conclusions. -AndrewDressel 14:48, 15 March 2007 (UTC)

Weird image that appears to be some sort of vandalism
Does anyone else see "Image:Foreskin penis cr07.jpg" at the top of the article page? The image does not exist, so it doesn't show, but a transparaent box covers the first paragraph of the article. I can find no trace of it when I edit the page nor in the history. It does not appear in a preview of the page and it does not appear in my view of any previous version, just in the current version of the article. -AndrewDressel 19:26, 7 November 2007 (UTC)
 * The vandalism was in the transcluded template: Template:TOCleft. SeveroTC 10:11, 14 November 2007 (UTC)
 * Phew! Glad you found it and got rid of it. -AndrewDressel 14:52, 14 November 2007 (UTC)

Reorganization
Any objections to moving most of the frame geometry section to the existing Bicycle and motorcycle geometry article? That would enable a more-comprehensive discussion of the topic in one place. This article is already 31k long, and moving some material out would help bring it back down to size. -AndrewDressel (talk) 23:24, 18 February 2008 (UTC)
 * Seems like a good idea :) SeveroTC 23:30, 18 February 2008 (UTC)

Fatigue
The current article states that "in contrast to some steel and titanium alloys, which have unlimited fatigue life, aluminum has no endurance limit" What is meant by this? The fatigue life of aluminum is *much* shorter than that of ti or steel. But Neither ti nor steel have an unlimited fatigue life. Aluminum, while not having an 'endurance life', as long as steel or ti certainly has an endurance life. I have bikes that have seen millions of load cycles and are still in one piece. Ender8282 (talk) 20:32, 3 April 2008 (UTC)
 * The endurance limit is the maximum cyclical stress that can be repeatedly applied without fatigue ever occuring. Aluminum doesn't have such a limit (a stress limit not a lifetime limit) so any repeated stress, no matter how small will eventually lead to failure. I've taken out this term because it's probably misleading as you say.Kallog (talk) 09:34, 4 April 2008 (UTC)

I see you took out the mention of unlimited fatigue life. It's true we can't know that it really is infinite, but this is how it's usually described. It's distinctly different from the finite-but-long life of alloys without an endurance limit. See here Bicycle frames may not be designed for unlimited fatigue life, but steel parts typically are so it seems safe to generalize to bicycle frames. Kallog (talk) 04:05, 28 April 2008 (UTC)
 * Before trying to address the issue here, I've spent some time trying to clean up the Fatigue (material) and Fatigue limit articles. It appears, from the authors I've cited and ASTM International that fatigue life is only defined in terms of a specified stress. Without specifying the stress, fatigue life is meaningless. In that case, either fatigue limit or endurance limit are the terms that should be used here to distinguish between the nature of steel and aluminum. Steel has a clearly defined stress limit below which prevailing current practice assumes that fatigue failure will never occur. Aluminum does not. I found no mention, in any of the textbooks I examined, of the new research that suggests that this limit does not actually occur even in steel. That doesn't mean I contest the new research, but suggests that this article on bicycle frames need not take it into account.-AndrewDressel (talk) 18:48, 28 April 2008 (UTC)
 * Looks good, you've managed to avoid having to say how it applies to bicycles, which we probably don't know. Kallog (talk) 00:08, 29 April 2008 (UTC)

humbert
The {{for| template at the top of this article mentions Humber (bicycle). The article referred to is short, but seems to refer to a bicycle manufacturer who made a number of novel frame types, but not a frame type in itself. Could someone clarify this?--Keithonearth (talk) 06:50, 1 October 2008 (UTC)


 * That is true. Articles about the frame types would be ideal, but the Humber bicycle article makes the only mention of those frame types that I know of. If we remove the Humber bicycle article from the bicycle frame article, I think the information about other frame times will be essentially lost. -AndrewDressel (talk) 11:23, 1 October 2008 (UTC)


 * That's a good point, I'd say your right and the humbert link should stay, but could we make it more clear?

{{for-text|frame designs other than the diamond frame|step-through frame, recumbent bicycle and others as manufactured by Humber (bicycle)}}


 * But maybe it's getting too wordy.--Keithonearth (talk) 18:28, 1 October 2008 (UTC)

Claims in "Carbon Fibre" section
"The ability to design an individual composite tube with properties that vary by orientation cannot be accomplished with any metal frame construction commonly in production."

This is false; any tube that does not have rotational symmetry (e.g. one with a rectangular cross section) has properties that vary by orientation. If the statement were qualified to say "a symmetrical" instead of "an individual", this would be rectified. However, the sentence would still read "The ability to design [...] a composite tube [...] cannot be accomplished with any metal frame construction." —Preceding unsigned comment added by PaulKishimoto (talk • contribs) 06:12, 21 October 2008 (UTC)

Steel Generally Used
I added a request for a reference to the claim that 'generally frame tubes are made of steel'. My experience working at a bicycle shop in Tucson, AZ is that most new bikes are being made of Aluminum. I would say that this is true both of bicycle shop brands and department store brands. I believe the statement to not reflect the current trends of the last 5 years. Historically I don't argue that bicycle were made of steel but I don't think that this is the current trend. Please add a reference to back this up or remove it. Ender8282 (talk) 20:25, 12 February 2009 (UTC)


 * While I agree with you for the most part, I do think this is another example of how difficult it is to make global statements on how one bike thing is more common than another. Surely Chinese and Indian roadsters are some of the most common bikes globally?  They're made from "gas pipe" steel, lugged.  How about saying that steel and alu are the most common frame materials?--Keithonearth (talk) 06:55, 13 February 2009 (UTC)

What is this article about?
A resent change to the opening blurb of this article has specified that the article is only about Diamond frames. This seems unnecessary to me, and even undesirable. I would suggest that we should have an article that is an overview of bicycle frames in general, and that we shouldn't exclude other frame types from this article. I'd also say that it is appropriate for an article giving an overview of bicycle frames in general, to mainly talk about the most common one: the diamond frame. The second most common one, the step-through frame shares many characteristics with the diamond frame, and all the tubes have the same name, construction technique and materials are virtually identical. Of the 3 links provided in the header: step-through frame, recumbent bicycle and Humber (bicycle), Step-through is nominally about a bicycle frame, but in fact discusses the type of bicycle in general. The other two articles are not about bicycle frames at all: the recumbent article talks about a wide range of characteristics about this style of bicycle, but on skimming through did not have any info about the frame construction, materials, or anything else. The Humbler article is about an obscure and obsolete bicycle manufacturer that at one time made a non-standard frame. It has little info. I propose changing the header to "This article describes bicycle frames in general with emphasis on diamond frames. For more non-diamond frames see step-through frame, recumbent bicycle and Humber (bicycle)."--Keithonearth (talk) 06:52, 9 April 2009 (UTC)


 * I like your suggestion. -AndrewDressel (talk) 13:43, 9 April 2009 (UTC)


 * Ok, I've done it, with the minor modification that I said ...with emphasis on diamond and step-through frames. I did this because there is so much overlap between the two.  If anyone feels this is inappropriate and thinks my first suggestion is better, feel free to edit it.--Keithonearth (talk) 18:54, 10 April 2009 (UTC)

Track bike bottom bracket height
I've copied this here from the Track bike article in hopes of finding an answer. -AndrewDressel (talk) 13:41, 2 May 2009 (UTC)

"higher bottom bracket for additional cornering clearance." I've often heard this, but have never heard how much higher.


 * All I can find in UCI regulations (http://www.uci.ch/imgArchive/Rules/1gene-E.pdf) is:
 * Technical specifications
 * Except where stated to the contrary, the following technical specifications shall apply to bicycles used in road, track and cyclo-cross racing.


 * 1.3.015 The distance between the bottom bracket spindle and the ground shall be between 24 cm minimum and maximum 30 cm.


 * Cannondale (http://www.cannondale.com/bikes/03/geo-40.html) lists the bottom bracket height for their track bike is 28.2 cm.


 * Fuji (http://www.fujibikes.com/geometry.asp?bike_id=17) lists the bottom bracket height for their track bike is 29.2 cm.


 * Others, such as Bianchi and Surly, just say "track legal". What does that mean exactly?

I get the general "heigher for pedal clearance with a fixed gear", but it would seem also to depend on crank arm length. Does anyone know what the real requirement is? How would a particular bicycle at a track event be found to be legal or illegal?-AndrewDressel 00:03, 20 October 2007 (UTC)


 * Crank arm length affects the leverage on the gear. So if you have a long crank arm, it has to be mounted high enough to clear corners. I belive there is a mathematical formula but I do not know it. I personally use 65 size crank arms and a bottom bracket that messures 11 and 3/4" from the ground to center of allen bolt attaching crank arms. —Preceding unsigned comment added by Mrmike23 (talk • contribs) 18:12, 9 December 2007 (UTC)


 * We sure would like to see that formula. Anybody? -AndrewDressel (talk) 13:29, 2 May 2009 (UTC)


 * I'm confused by the reasoning here. Surely a track bike will lean less relative to the surface on which it is riding; the whole point in a banked track is to stay more perpendicular to a leaning bicycle than a flat surface? 86.0.203.120 (talk) 15:27, 24 August 2008 (UTC)


 * That a track bike leans less on a banked track is only true when the bike is following a line concentric (I suspect that is not the correct word, but I don't think parallel is correct either, and I can't find a better alternative) to the track. During turns to avoid another cyclist, or when the bike leans from side to side during a sprint, the bank of the track is not a factor, and it is important that the pedals, which are of course forced to rotate by the forward motion of the bike, not strike the track surface. The questions remains: "What exactly does 'track legal' mean?" -AndrewDressel (talk) 17:32, 25 August 2008 (UTC)

Reynolds 531 vs 4130 Chromoly
While Reynolds 531 is similar to 4130 Chromoly, and they both have Manganese, Rynolds 531 has nearly twice as much.
 * {|class="wikitable"

! SAE grade ! % Mo ! % C ! % Mn Its mechanical properties and response to heat-treatment are broadly similar to the AISI 4130 standard alloy steel. -AndrewDressel (talk) 14:21, 25 September 2009 (UTC)
 * + Alloy composition (by weight)
 * 4130 || 0.15 - 0.25 || 0.28 - 0.33 || 0.40 - 0.60 ||
 * 531 || 0.25        || 0.35        || 1.5   ||
 * }
 * 531 || 0.25        || 0.35        || 1.5   ||
 * }
 * }


 * More importantly, it's not "Reynolds 531" unless it's made by Reynolds and says 531 on it. Particularly for UK bikes in older decades, "Reynolds 531" is also a notable product brand in its own right, as recognisable as Reynolds themselves and far more recognisable than a 4130 SAE code. Even if these had been identical alloys by definition, any article around cycling still needs to preserve use of the term "Reynolds 531", on account of its familiarity with so many of the readers. Andy Dingley (talk) 14:42, 25 September 2009 (UTC)


 * It was my impression that many tube-set branding refered to not just the alloy itself but also to the wall thickness, both at the butts and in the middle. Does anybody know if this is true with 531 as well?  --Keithonearth (talk) 18:25, 25 September 2009 (UTC)

BB shell width
At one point the article says "The shell width influences the Q factor or tread of the bike." I can see how the spindle length affects tread, but not shell width. If others agree, could this sentence just be removed?

Thanks, Stuart H. Alden (talk) 12:37, 2 January 2010 (UTC)


 * Here's a quote from The Q-Factor, by Warren Beauchamp with emphasis added by me:


 * If you still need to get narrower, you can use a custom BB. Phil Wood makes a 96mm BB as a stock item, which requires a narrowed BB shell, and a special Phil tool to install it.


 * A sufficiently narrow bottom bracket will not fit in a sufficiently wide brottom bracket shell. -AndrewDressel (talk) 13:02, 2 January 2010 (UTC)

Titanium Brazing References
There is an interesting general history of working with titanium, as I think it's relatively new and techniques may have been guarded by industry or the military. In industry, Ti is often brazed, including to dissimilar metals. Bike frames are usually welded due to the cost of brazing in a workspace purged with inert gas, and possibly a larger brazing surface area requirment. Here are some links that might get this started.


 * http://www.classicrendezvous.com/USA/Pino_Moroni_main.htm
 * http://www.titaniumexposed.com/titanium-bicycle-frame.html
 * http://www.titanium-brazing.com/

Cantiliever?
Where does the term cantilever frame come from? It is technically incorrect, since there are no cantilevers in the frame that aren't in just about every other type - namely the handlebars, front forks and seat post. Is it in common use? If not, a more accurate term should be used. --Triskele Jim 17:22, 2 January 2013 (UTC)


 * "Cantilever" is a term in bicycle marketing, not engineering. These are the people who gave us "melt forging" as a pseudonym for casting, because forged parts were seen as more prestigious than cast.
 * In engineering terms, it seems to be a consideration of the bike frame as a simple combined top tube and seat stay, balanced on either side of the seat post. This would class as a balanced cantilever, much as the Forth Bridge.
 * The distinction is that the "classic" double triangle frame is avoiding the structural problems of building a robust cantilever (it needs an extra-strong tube) by instead moving towards a two-dimensional spaceframe (It doesn't achieve this, but it's a move towards it). In these, bending moments in tubes (which tend to make the tubes crimp, fold and collapse) are replaced by compression forces along a perpendicular tube (much stronger, for a comparable tube).
 * There are other bike frames with a better engineering claim to being cantilevers, particularly most swing-arm rear suspension frames. Andy Dingley (talk) 18:19, 2 January 2013 (UTC)

Cardboard
Recently a section on cardboard bike frames was added, with a reference. Then it was deleted, presumably because it was not notable and/or not in production.

It is quite notable, I believe, as evidenced by the extensive and mainstream news coverage it received:
 * NPR
 * The LA Times
 * CBS news
 * Christian Science Monitor
 * The Economist
 * SlashGear

That isn't necessarily the only inclusion criteria. Is it? Maybe it is. We already list Magnesium, Thermoplastic, and Wood, but I don't believe those materials are "in production" now. At least the article currently doesn't suggest so.

What say ye? -AndrewDressel (talk) 19:59, 26 January 2013 (UTC)
 * Quite notable bikes have been made in large numbers of thermoplastic, magnesium and wood. The cardboard bike is yet a one-off. Strictly speaking it is just another composite material, with a main material (cardboard) and a reinforcing agent (the resin), just like carbon bikes are really resin reinforces woven carbon strings. Not sure the cardboard technology requires a whole section in the article, perhaps just a small note? Keanu (talk) 20:15, 26 January 2013 (UTC)


 * I'm the one who erased the section on cardboard bicycle frames, with the comment "removing non-notable non-production cardboard bicycle". I believe in the interest of keeping the article focused it's better not to include the cardboard  section.  While the prototype has been in the news a fair bit over the last few months, I do not believe that it is worth mentioning as it is only a prototype.  The examples in Andrew's comparison (Magnesium, Thermoplastic, and Wood), while rare, have made it beyond the prototype stage, in to production -- though not to commercial success.  As such I'd like to see cardboard left out unless it actually makes it into production.  --Keithonearth (talk) 01:44, 27 January 2013 (UTC)

Sounds good. Thanks for the quick feedback. I think I'll try to put together a cardboard bicycle article anyway, to take advantage of all the notoriety. It is at least significant as the Shweeb. -AndrewDressel (talk) 15:35, 27 January 2013 (UTC)

Open frame
It appears that "open frame" is used as a synonym for step-through frame, as the article currently states. It is difficult to find any references for this, however, that are not private listings on tag-sale sites or advertising copy on commercial sites, which are not suitable references. Never-the-less, one reasonable reference has been found, so the mention can stay. That does not mean, however, that the synonym deserves undue weight. There is no reason to insert it every time "step-through", the name chosen for the article title, is used. -AndrewDressel (talk) 16:04, 2 April 2013 (UTC)


 * Agree with Andrew. Also, open bicycle frame redirects to step-through frame, so never need to wikilink both in close proximity. Murray Langton (talk) 16:24, 2 April 2013 (UTC)


 * (copied from User_talk:AndrewDressel) My contributions to the bicycle frame page were both constructive and argumented. Please restore the changes to make Wikipedia useful to its readers. As I stated, Open frame is the accepted term, both on commercial websites and colloquially.  People searching should be able to find it.  Here is also an old reference for its use, -90.38.132.97 (talk) 17:23, 2 April 2013 (UTC)




 * Funny thing about that reference you cite: I found it and inserted it. Thus, I have a pretty good idea how hard it was to find. As things stand now, Wikipedia readers will have no trouble finding "open frame bicycle". Any further insertions of that synonym will simply be giving it undue weight. Further discussion of this topic belongs here. -AndrewDressel (talk) 18:27, 2 April 2013 (UTC)


 * Thank you Andrew for finding the old reference, since it gives it some legitimacy in non-commercial circles as well. In commercial sites ladies' and open frame are the accepted terms (and open frame was the more PC, gender-neutral of the two). It's not too clear why commercial sites are not good references for a common use of a term, but I also see the point that there are now enough references to open frame, so people who look for it will find it. Overall it seems a reasonable description has been made. Thanks again. 90.38.132.97 (talk) 21:58, 2 April 2013 (UTC)

Cross frame vs Truss Frame
Someone who knows a bit more about this than me might like to do an edit. But in my opinion the photo illustrating a modern "truss frame" (something I'd not heard of before) looks very like what I know of as a cross frame. For example, this is a picture of a 1917 Cross-Frame Raleigh: http://www.oldbike.eu/museum/wp-content/uploads/2012/04/1917_Raleigh_Crossframe_03.jpg. And someone else might wish to add that the cross-frame stayed in the UK market as the police continued to use it, in the belief that it was that much stronger (policemen back then being fairly large!).Thomas Peardew (talk) 18:41, 1 April 2014 (UTC)
 * Isn't a truss frame (old or new) generally a doubled top tube? Often the lower top tube is curved upwards and tied to the upper in the middle. Andy Dingley (talk) 20:19, 1 April 2014 (UTC)

Downtube?
Somebody should add a picture showing the names of the different parts of the frame. The article talks about a "downtube" in a couple of places, but doesn't explain which part that is. I'm guessing it's the diagonal member going from the handlebars to the crank, but maybe it's the vertical member that the seat sits on top of? -- RoySmith (talk) 20:50, 1 November 2014 (UTC)


 * Do you mean something like the picture currently in the frame tubes section of the article? -AndrewDressel (talk) 21:15, 1 November 2014 (UTC)


 * Hmmm, uh, yeah. My bad.  I searched for "downtube" and didn't find it.  Should have searched for "down tube".  -- RoySmith (talk) 22:49, 1 November 2014 (UTC)

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Weird frames
It seems that first three have different parts that are "loose" Not sure if they fall in any of the categories in the article or are new category so I put them here. 95.178.222.9 (talk) 02:18, 23 April 2020 (UTC)
 * swingbike (1970is)
 * Wobblebike, name coined in 2000, street performer's bike that bends in the middle.
 * Тhe Trocadero Fixie, experimental bicycle (at first) that features a twisting frame in the middle, it's for tricks and drifts but it also shrinks the turning radius by a lot, maybe inspired by wobblebike (around 2016)
 * helyx bike, described as twin steer bike
 * Kevin Scott's "bike that bends around a post" (around 2010)
 * frames for bikes like varibike fr3 or twicycle that have hand and leg cranks
 * flying rider seatless bike
 * nitro rail bike
 * frames like one on The Bicymple