Table of Contents

c2020.jpg t2024.jpg Created with GIMP t81.jpg Created with GIMP t84.jpg Created with GIMP t93.jpg Created with GIMP Processed By eBay with ImageMagick, z1.1.0. ||B2 c95.jpg


Tubing

Before the the coming of carbon in 1990, all mountain bikes started their life as a box of metal tubes. Before Cannondale and Klein made aluminum commonplace in 1984, 99% of all MTBs were built from steel tubing1) 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:

Have bicycles regressed? Is the metal in the Huffy that much denser? Solid iron, maybe? Did the unobtanium tubing used in the René Herse make it weaker than the Huffy?

Strong, Light, Cheap… Pick Two. 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 certain department stores. So, is the best tubing simply what is strong and light? Well, yes…

Gary Fisher's 1942 Schwinn Excelsior
Gary Fisher's converted 1942 Schwinn Excelsior still holds the Repack course record for a rigid bike. Weight: approximately 50 pounds. More info at: Charlie Kelley's website.

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:

Ritchey Logic tubing
Bundles of Ritchey Logic tubing waiting to be mitered and TIG welded. ritcheyloggic
Reynolds tube sampler
Reynolds tube sampler reynoldstechnology
Columbus tubing
Columbus tubing on fresh frames at Mason Cycles. base-mag
Angelo Luigi Colombo and the Cannibal
Angelo Luigi Colombo and the The Cannibal. facebook


Manufacturers

Choose


Decal Timelines

Maker1970 1980 1990
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
Reynolds rlogo.jpg
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
Maker1970 1980 1990

Notes:

  • Decals after 1973 had “Reynolds Tube Co Ltd”
  • Decals after 1981 had “Ti Reynolds Ltd”
  • Decals after 1985 had “Ti Reynolds 531 Ltd”
  • Decals after 1989 had split “Reynolds” logo
  • Decals after 1995 had un-split, simple “Reynolds” logo
2024/03/12 17:01 · mtbtimeline
Maker1970 1980 1990
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
Columbus collogo.jpg c70.jpg Created with GIMPCreated with GIMPCreated with GIMPCreated with GIMPCreated with GIMPProcessed By eBay with ImageMagick, z1.1.0. ||B2c95.jpgProcessed By eBay with ImageMagick, z1.1.0. ||B2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
Maker1970 1980 1990

Notes:

  • Early rectangular decals did not say Columbus at the bottom.
  • Decals after 1972 were a red dove on gold foil.
  • Decals after 1975 had a white dove on a red background.
  • Decals after 1978 had a fatter dove with no name.
  • Decals after 1984 often had the tubeset name.
  • Decals after 1988 put Columbus at the top with a funky background.
  • Starting the 1990s, decals started using some English, as in “differential shape butted.”
  • Decals after this use the ® symbol, funky backgrounds, Columbus at the top and white dove. Other colors and words will change depending on the tubset. Dating these requires a set of Columbus catalogs.
2024/03/16 14:19 · mtbtimeline
Maker1970 1980 1990
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
Tange t81.jpg t84.jpgProcessed By eBay with ImageMagick, z1.1.0. ||B2t88.jpgt93.jpgt94.jpg
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
Maker1970 1980 1990

Notes:

  • 1984: Prestige introduced
  • 1985: Prestige MTB introduced
  • 1986: G & E letters attached in the middle, N & G partially attached
  • 1993: G & E letters attached at the top, A has no cross
  • 1994: Blue label
2024/03/22 20:37 · mtbtimeline

Tech Tutorial

The first 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 pneumatic tyres. When Reynolds introduced the double butting process, it started a new era in lighter and stronger bicycles. By 1938 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?

 Reynolds 953
Stack of fresh Reynolds 953 tubing. cyclist.co.uk


Material Strength: A Quick Primer

In the chart to the right –>

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 rolling tube blocks around the dent to squeeze it all back to shape 4). Young's modulus is how stiff the metal is: how much force it takes to bend5). Bending is related to 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 infinite6) 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.

MaterialYield Strength MPa Tensile Strength MPa 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

MaterialDensity (g/cm3)
Steel 7.85
Titanium 4.48
Aluminum 2.7
Carbon 1.75

Tech Resources:

 Stress vs Strain
Stress vs. Strain Curve wikipedia

failed steel
Double butted top tube crimped at the taper point.
peterverdone.
failed aluminum
Aluminum fatigue failure at seat stay.
reddit
failed titanium
Arc welding weakens tubing at the weld points. Titanium.
ebay
failed carbon
Shattered carbon.
bicycling.com


Butting

 Tange butting
Tange butting. The shorter butt side is marked with paint. 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 tubes7).

GaugeMillimeters Price in pence 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 Standard8). 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 tube9). 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:

Standard4ga 12ga20ga
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 wikipedia

Gauge Resources:

 single butting
Single Butted Tube fairing.com
 double butting
Double Butted Tube fairing.com
 bulge butting
Bulge Butted Tube fairing.com

2)
Comes with an optional reproduction Nivex derailleur.
3)
Force is measured in pounds/in^2, or kilos/cm^2 (aka MPa, Mega-Pascals, which is 10kg/cm^2
4)
Another problem with Reynolds 953 is that it's so hard that tools simply find it difficult to work or cut.
5)
All steel tubing has identical Young's modulus values. The difference is in the tube thickness.
6)
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 Goodman diagrams for a calculator on spring lifespan.
7)
Reynolds 1948 prices were for 4 tubes in shillings & pence.
8)
The BWG is averaged in 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 engineeringtoolbox
9)
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.