Reynolds 531 (pronounced 'five-three-one') is a

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Reynolds Technology Reynolds Technology is a manufacturer of tubing for bicycle frames and other bicycle components based in Birmingham, England established in 1898. History The Reynolds Tube Company was founded in 1898 by John Reynolds in Birmingham, England, b ...

Birmingham Birmingham ( ) is a City status in the United Kingdom, city and metropolitan borough in the metropolitan county of West Midlands (county), West Midlands, within the wider West Midlands (region), West Midlands region, in England. It is the Lis ...

in the United Kingdom, for a

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

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molybdenum Molybdenum is a chemical element; it has Symbol (chemistry), symbol Mo (from Neo-Latin ''molybdaenum'') and atomic number 42. The name derived from Ancient Greek ', meaning lead, since its ores were confused with lead ores. Molybdenum minerals hav ...

, medium-carbon

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

tubing that was used in many quality applications, including race car chassis, aircraft components and, most famously,

bicycle frame A bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. The modern and most common frame design for an upright bicycle is based on the safety bicycle, and consists of two triangles: a main triangle ...

tubing. It is one of a number of tubing types developed by Reynolds. Reynolds 531 "was the standard of excellence for many decades" among bicycle frame-building materials. And because of the availability of a wide range of butting, diameters and thicknesses of tubes, along with different stays and fork blades, it became the tubing of choice for most frame builders.

Details

Introduced in 1935 and for many years at the forefront of

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tubing technology, 531 cycle tubing has been superseded by more complex alloys and heat-treatment/ cold-forming cycles as Reynolds continues to compete with other manufacturers of steel for the bicycle industry.Reynolds Technology FAQ, retrieved 23 October 2011, http://reynoldstechnology.biz/faqs/materials/2 531 tubing became the tubing-of-choice for most framebuilders at least partly because of the huge range of butting, diameters and thicknesses of tubes along with different stays and fork blades available – helped by the willingness of Reynolds to make special tubes for certain manufacturers. Reynolds also made up complete 'sets' of tubing for different cycling applications – for example 531c (Competition), 531st (Super Tourist), 531ATB (All Terrain Bike) and so-on. This flexibility made 531 still competitive even after the introduction of more advanced alloys. The widespread use of TIG and MIG welding in cycle manufacture became a problem as 531 reacted poorly to the higher temperatures produced and 531 has been gradually phased out as a result. The most common like-for-like replacements for 531 are Reynolds 520 and 525 – a chrome-molybdenum tubing with very similar characteristics, but in addition to brazing, can also be welded. The 520 and 525 tubing are essentially the same thing. The difference being that 525 is made at Reynolds headquarters in Birmingham, England while 520 is made to the same specifications in Taiwan, saving transportation costs when supplying Taiwanese frame builders. The approximate alloying composition of 531 tubing is 1.5% Mn, 0.25% Mo, 0.35% C, and is similar to the old British BS970 En 16/18 steel (EN 16 is similar to grade BS970 605M36). Its mechanical properties and response to heat treatment are broadly similar to the AISI 4130 standard alloy steel, also used for bicycle frames, motorcycles, as well as aviation and motor-sport. This material was used to form the front subframes on the

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of the 1960s. Reynolds 531 is now only available by special order. The nearest available stock material is BS4t45 to Bs5T100 in accordance with BS6S100 conditions.Pro Formance Metals Ltd, http://www.proformancemetals.co.uk (T45) Reynolds has superseded this tube set with a number of innovations such as Reynolds 753 and the more current 853. Reynolds also produces stainless steel tube sets for bicycle frame building – these are 925 and 953.

References

{{Reflist Bicycle parts Steels History of science and technology in the United Kingdom