---- ===== Tubing ===== Before the the coming of [[https://en.wikipedia.org/wiki/Carbon-fiber-reinforced_polymers|carbon]] in 1990, all mountain bikes started their life as a box of metal tubes. Before [[canon:start|Cannondale]] and [[klein:start|Klein]] made aluminum commonplace in 1984, 99% of all MTBs were built from steel tubing((Other early Al frames include: [[cc:start|Cunningham, 1978 -> 1993]], [[snr:start|Speed & Research, 1982]], [[crotch:start|Crotch Rocket, 1983]], [[kettler:start|Kettler, 1984+]]...)) from dozens of suppliers, from gas pipe to Reynolds. MTBs with a quality steel sticker were a cut above the rest, and probably a lot lighter as well. How important are these stickers, other than in dating the bike? A full materials science primer will follow, but for now, consider two bicycles: * A 2024 [[https://www.homedepot.com/p/Huffy-Classic-Deluxe-26-in-Men-s-Cruiser-Bike-26648/304490184|Huffy Classic Deluxe]], complete with fenders, basket, rack and a chain guard. Single speed. * Weight: 47 -> 52 pounds. * Cost new today: [[https://www.dickssportinggoods.com/p/huffy-mens-deluxe-perfect-fit-26-cruiser-bike-23hufm26mnsdlxcrscrs/23hufm26mnsdlxcrscrs?sku=25724169&srsltid=AfmBOop6CCvg6PdfFvCjor3Q1-L1n4-wOXyrxlaK82SQ4_28iHEPqrByrmI|$219.99]]. * A 1938 [[https://www.renehersecycles.com/80-years-of-rene-herse-cycles/|René Herse]] touring bike, complete with fenders, bottle cage, pump, racks front and back, light and bell. 10 speeds. * Weight: 17.50 pounds. * Cost new (reproduction) today: [[https://www.renehersecycles.com/shop/bikes/80th-anniversary-rene-herse-bike-down-payment/|$14,200]]. ((Comes with an optional reproduction [[https://www.renehersecycles.com/shop/components/derailleurs/11sp-nivex-rear-derailleur/|Nivex derailleur]].)) Have bicycles regressed? Is the metal in the Huffy that much denser? Solid iron, maybe? Did the [[https://en.wikipedia.org/wiki/Unobtainium|unobtanium]] tubing used in the René Herse make it weaker than the Huffy?

**Strong, Light, Cheap... Pick Two**. [[bontrager:start|Keith Bontrager]]

The René Herse was made of Reynolds 531 tubing, which debuted three years before, reducing some frame weights by nearly 50%. Double butting, tempering and careful blending of alloys can produce tubing which is **10x** stronger then mild steel, allowing for Reynolds 531 frames to weigh 3.75 pounds, where some of the original MTB klunkers had frames over 20 pounds. Any of the tubing manufacturers documented here make excellent tubing and any MTB with their decals is a cut above the heavy and weak gas-pipe bikes sold in [[https://www.walmart.com/browse/sports-outdoors/mountain-bikes/4125_1081404_5150992_7867034?max_price=110|certain]] department stores. So, is the best tubing simply what is strong and light? Well, yes... {{prehist:gary.jpg?300|Gary Fisher's 1942 Schwinn Excelsior}} \\ Gary Fisher's converted 1942 Schwinn Excelsior still holds the [[people:repack|Repack]] course record for a rigid bike. Weight: approximately 50 pounds. More info at: [[http://sonic.net/~ckelly/Seekay/mtbwelcome.htm|Charlie Kelley's website]]. {{herse47.jpg?300|1947 René Herse}} \\ 1947 René Herse, built with Reynolds 531 tubing. Since Reynolds 531 debuted in 1935, road bikes could often achieve weights under 18 pounds and remain reliable. The drillium saddle probably helped. Overall resources: * [[https://gravelcycling.wordpress.com/2016/07/07/steel-the-different-types-of-steel-in-bike-frames/|types of steel]] * [[https://www.bretonbikes.com/homepage/cycling-article-blog/163-steel-tubing-for-cycle-tourists|bretonbikes - tubing]] * [[https://www.bretonbikes.com/homepage/cycling-article-blog/200-stiffness-in-bicycle-frames|bretonbikes - stiffness]] * [[https://valvejob.wordpress.com/2016/01/18/bike-frame-design-the-influence-of-tubing-diameter-and-wall-thickness/|tubing sizes]] * [[https://valvejob.wordpress.com/2020/05/21/bike-frame-design-strength-of-steel-frame-tubing/|frame design]]

{{bundles.jpg?400|Ritchey Logic tubing}} \\ Bundles of Ritchey Logic tubing waiting to be mitered and TIG welded. [[ https://ritcheylogic.com/blog/the-ritchey-guide-to-butted-steel-for-bicycle-frames|ritcheyloggic]] \\ {{r953.jpg?400|Reynolds tube sampler }} \\ Reynolds tube sampler [[https://www.reynoldstechnology.biz/reynolds-attends-first-in-person-show-bespoked-2021/|reynoldstechnology]] \\ {{colframes.jpg?400|Columbus tubing}} \\ Columbus tubing on fresh frames at [[https://masoncycles.cc/|Mason Cycles]]. [[https://www.base-mag.com/steel-is-real/|base-mag]] \\ {{calc.jpg?400|Angelo Luigi Colombo and the Cannibal}} \\ Angelo Luigi Colombo and the [[https://en.wikipedia.org/wiki/Eddy_Merckx|The Cannibal]]. [[https://www.facebook.com/Columbus1919/photos/pb.100064599733161.-2207520000/3957729967588746/?type=3|facebook]]

---- ===== Manufacturers ==== ==== Choose ==== |< 100% 20% 20% 20% 20% 20% >| |@#F0F0F0:[[{tubing:r531_1989.png?0x100}reynolds:start|Reynolds]] | @#F0F0F0:[[{tubing:c2020.jpg?0x100}columbus:start|Columbus]]|@#F0F0F0:[[{tubing:t2024.jpg?0x100}tange:start|Tange]]|@#F0F0F0:|||

---- ===== Decal Timelines ==== {{page>:timeline_reynolds}} {{page>:timeline_columbus}} {{page>:timeline_tange}}

---- ===== Tech Tutorial ===== The first [[https://en.wikipedia.org/wiki/Safety_bicycle|Safety Bicycles]] of the 1880s weighed 42 pounds, with solid rubber tires and no gearing. The were built with steel tubing joined with soft iron castings. By 1897, before Reynolds double butted tubing, the safety bicycles were able to reduce their weight to as low as 22 pounds due to the creation of lighter and stronger steel alloys and [[https://en.wikipedia.org/wiki/John_Boyd_Dunlop|pneumatic tyres]]. When [[https://en.wikipedia.org/wiki/Reynolds_Technology|Reynolds]] introduced the double butting process, it started a new era in lighter and stronger bicycles. By 1938 [[https://www.renehersecycles.com/80-years-of-rene-herse-cycles/|René Herse]] was producing touring bikes, complete with fenders, rack, light and bell weighing a feather light 17.50 pounds, built using thin Reynold 531 tubing. \\ Reynold 531 was an alloy of 98.1% Fe, 1.4% Mn, 0.30% C, and 0.20% Mo. How is this alloy composition its secret sauce? How is 531 better than other tubing? Does it better resist breaking or crimping? Is it easier to work with? More expensive? What do other manufacturers, such as Columbus use? What is strength anyway?

{{rtub.jpg?400| Reynolds 953}} \\ Stack of fresh Reynolds 953 tubing. [[https://www.cyclist.co.uk/in-depth/reynolds-men-of-steel|cyclist.co.uk]] \\

---- ===== Material Strength: A Quick Primer ===== In the chart to the right --> * **stress** := the amount of force((Force is measured in pounds/in^2, or kilos/cm^2 (aka MPa, Mega-Pascals, which is 10kg/cm^2)) applied. * **strain** := the amount the material has deflected or bent. * **yield strength** := the point where the bend becomes permanent or deformed. Think of bent tube becoming dented or creased. * **ultimate strength** := the most stress a material can endure without breaking, aka "tensile strength" or "ultimate tensile strength." Bicycle owners should probably care more about yield strength instead of UTS (ultimate tensile strength), as a deformed tube is often thought of as a failed tube. Tubing manufacturers tend to publish UTS numbers, because they're much bigger. If the gap between the yield strength point and the fracture point is small, the material is considered to be **//brittle//**, such as glass. Else, it's **//elastic//** or **//ductile//**. For example, Reynolds 953 is 2.7 times stronger than Reynolds 531. Yet 531 is fairly elastic and is easier to repair than 953, such as by [[https://www.paragonmachineworks.com/frame-building-tools/tube-blocks.html|rolling tube blocks]] around the dent to squeeze it all back to shape ((Another problem with Reynolds 953 is that it's so hard that tools simply find it difficult to work or cut.)). **//Young's modulus//** is how stiff the metal is: how much force it takes to bend((All steel tubing has identical Young's modulus values. The difference is in the tube thickness.)). Bending is related to [[https://en.wikipedia.org/wiki/Fatigue_limit|fatigue limit]], which is the point where bending starts to wear on the material. For steel, this is often about half the yield point. Steel can withstand an //infinite//((A well designed spring should last billions of cycles. Not all springs achieve this. Think of the comparison between an internal combustion engine valve spring, which lasts about 20 billion cycles, versus a garage door spring, which is only 10,000 cycles. See [[http://springcalculator.com/Goodmandiagram.html|Goodman diagrams]] for a calculator on spring lifespan.)) amount of bending without wear until its bent near the fatigue limit. A well designed steel spring it will be springy until the end of time, or rusts claims it. Similarly, a well designed bicycle frame will never flex past its fatigue limit - which, of course, is very far from its yield and ultimate strengths. Aluminum has no fatigue limit at all, so that any bending will degrade the material and cause it to fail, eventually. Typically, aluminum frames and components are overbuilt with this in mind to keep them alive for decades. |< 100% 40% 20% 20% 20% >| ^^^^^ | @#F0F0F0:**Material**| @#F0F0F0:**Yield Strength MPa** |@#F0F0F0:**Tensile Strength MPa** |@#F0F0F0:**Frame Weight 56cm** | |Cheep steel |240 |320 || |4130 cold drawn |482 |655 || |Reynolds 525 (4130) |600 |700 || |Reynolds 531 |695 |803 |2200 | |Columbus Cromor |700 |750 || |Columbus SL, SP |735 |835 || |Columbus Niobium |750 |1150 || |Reynolds 725 |880 |1080 || |Reynolds 753 |900 |1100 |1502 | |Columbus Omnicrom |920 |1450 || |Columbus XCR |950 |1450 || |Reynolds 853 |1000 |1280 || |Reynolds 953 |1900 |2050 |1300 | ||||| |Carbon |N/A |1600 |1000 | |Ti |500 |620 |1542 | |6061 Al |270 |310 |1700 | === Densities === |< 100% 30% 30% 40% >| ^^^^ | @#F0F0F0:**Material**| @#F0F0F0:**Density (g/cm3)** || |Steel |7.85 |@#F0F0F0:| |Titanium |4.48 |@#F0F0F0:| |Aluminum |2.7 |@#F0F0F0:| |Carbon |1.75 |@#F0F0F0:| **Tech Resources:** * [[https://www.reynoldstechnology.biz/faqs-on-reynolds-steel-tubing/materials/]] * [[https://valvejob.wordpress.com/tag/bike-frame-design/]] * [[https://en.wikipedia.org/wiki/Reynolds_Technology]] * [[https://bike.bikegremlin.com/11144/bicycle-frame-materials-explained/]] * [[https://bike.bikegremlin.com/11843/metallurgy-for-cyclists/]] * [[https://www.framebuilding.com/Tubing%20Materials.htm]] * [[https://gravelcycling.wordpress.com/2016/07/07/steel-the-different-types-of-steel-in-bike-frames/]] * [[https://www.classiclightweights.co.uk/lightweight_extras/sculptured-in-steel-the-three-historic-lightweight-frame-designs-and-beyond/]] * [[https://donard.cc/blog/tech-an-introduction-to-capillary-motion-in-bicycle-joints]]

{{stress.png?400| Stress vs Strain}} \\ Stress vs. Strain Curve [[https://en.m.wikipedia.org/wiki/Ductility_(Earth_science)|wikipedia]] \\ {{fail_steel.jpg?300|failed steel}} \\ Double butted top tube crimped at the taper point. \\ [[https://www.peterverdone.com/the-bird-is-down-or-how-a-bike-frame-should-fail|peterverdone]]. \\ {{fail_al.png?300|failed aluminum}} \\ Aluminum fatigue failure at seat stay. \\ [[https://www.reddit.com/r/gravelcycling/comments/vfavmm/thursday_i_learned_about_flexing_aluminium/|reddit]] \\ {{fail_ti.jpg?300|failed titanium}} \\ Arc welding weakens tubing at the weld points. Titanium. \\ [[https://www.ebay.com/itm/115444170113|ebay]] \\ {{fail_carbon.jpg?300|failed carbon}} \\ Shattered carbon. \\ [[https://www.bicycling.com/bikes-gear/a43350616/should-you-buy-a-repaired-carbon-frame/|bicycling.com]] \\

---- ===== Butting ===== {{butting.jpg?600| Tange butting}} \\ Tange butting. The shorter butt side is marked with paint. [[https://www.tange-design.com/tubing_list.php?type_sn=1|tange-design]] All quality bicycle tubing since 1898 have included double butting, which have thicker ends than in the middle, saving weight while retaining strength. A 1948 Reynolds price list has the following available dimensions and prices for 1" top tubes((Reynolds 1948 prices were for 4 tubes in shillings & pence.)). |< 100% 35% 35% 15% 15%>| ^^^^^ | @#F0F0F0:**Gauge**| @#F0F0F0:**Millimeters** | @#F0F0F0:**Price in pence** | @#F0F0F0:**Quality** | |19 straight |1.07 |28d |A | |20 straight |.89 |38d |HM | |22 straight |.71 |40d |531 | |19 x 22 x 19 |1.07 x .71 x 1.07 |38d |A | |20 x 24 x 20 |.89 x .56 x .89 |56d |HM | |21 x 24 x 21 |.81 x .56 x .81 |60d |531 | This assumes that Reynolds was using the Birmingham Wire Gauge Standard((The BWG is averaged in [[https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/10.1046/j.1365-2044.1999.00895.x|The story of the gauge]]. There were 28 different Birmingham Wire Gauge standards. The Reynolds Tube Co. Ltd. probably had their own. See "The Story of the Gauge" and [[https://www.engineeringtoolbox.com/BWG-wire-gage-d_508.html|engineeringtoolbox]])). The shorthand for these buttings is written as 1/7/1 for "A" or 8/5/8 for "531" tubing. Bicycles are often made with a mix of buttings, depending on size, style and rider weight. Today, the thinnest Reynolds 953 is available .55 x .35 x .55mm for a 1 1/8" top tube((The mix of imperial and metric measurements for bicycles persists. Mountain bike wheel rim diameters are in inches. Mountain bike wheel hub widths are in millimeters. And frames are sized in cm or inches but frame tube widths are in inches.)). That is, if you can find 953, as production has been halted on that strongest of their tubing. Reynolds 531 is also no longer produced. Gauge is old British wire measurement ostensibly in units of a fraction of an inch. Sort of. There are 55 different sets of gauges from sheet metal to music wires. Some gauge examples in fractions of an inch: |< 100% 40% 20% 20% 20%>| ^^^^^ | @#F0F0F0:**Standard**| @#F0F0F0:**4ga** |@#F0F0F0:**12ga**|@#F0F0F0:**20ga**| |US steel sheet standard |.2344 |.1094 |.0375| |British Standard Wire Gauge |.232 |.104 |.032| |Birmingham Wire Gauge |.238 |.109 |.035| |US aluminum sheet standard |n/a |.0808 |.032| |US zinc sheet standard |.008 |.028 |.070|

The use of gauge number is discouraged as being an archaic term of limited usefulness not having general agreement on meaning. ASTM International, as cited in [[https://en.wikipedia.org/wiki/Sheet_metal#Gauge|wikipedia]]

Gauge Resources: * [[https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/10.1046/j.1365-2044.1999.00895.x]] * [[https://en.wikipedia.org/wiki/Sheet_metal#Gauge]] * [[https://www.engineeringtoolbox.com/BWG-wire-gage-d_508.html]]

{{butt2.jpg?300| single butting}} \\ Single Butted Tube [[https://www.fairing.com/butted-tubing|fairing.com]] \\ {{butt4.jpg?300| double butting}} \\ Double Butted Tube [[https://www.fairing.com/butted-tubing|fairing.com]] \\ {{butt3.jpg?300| bulge butting}} \\ Bulge Butted Tube [[https://www.fairing.com/butted-tubing|fairing.com]]