Saturday, December 28, 2013

Reynolds 531: Classic Tubes

Look at great bikes from the classic era, and one thing you'll find on many of them is a little sticker announcing the manufacturer of the tubing used in the frame. And for a long time, more often than not, chances are that little sticker said "Guaranteed Built With Reynolds 531."

The history of Reynolds Tubing goes back almost to the beginning of the "safety bicycle." Alfred M. Reynolds invented the process for butted tubing in 1887 and went on to found the Patented Butted Tube Company -- later renamed Reynolds Tube Co. Ltd. Over the decades, the Reynolds name became virtually synonymous with quality bicycles.

The technical process of butting tubing is more than I want to get into in this article and can be found elsewhere pretty easily for those who are interested, but it essentially boils down to making tubing with a varied wall thickness -- where the tubing is thicker at the ends where more strength is needed, but thinner in the middle section to reduce weight. Many riders believe that butting also improves ride quality, resulting in a more "lively" ride, though that's a little harder to quantify.

Earlier versions of Reynolds tubing were called HM, for "High Manganese," but in 1935 the company introduced "531" which, after butting, was regarded as a major breakthrough in strong, lightweight bicycle tubing. Butted 531 was considered revolutionary and quickly became the tubing of choice for most builders. The 531 name is a reference to the metallurgical components of the tubing - five parts manganese, three parts carbon, one part molybdenum. In general terms, it can be referred to as "manganese-molybdenum" or "manganese-moly" but should not be referred to as "chrome-moly." Some of the legends associated with Reynolds 531 are that it was used in the chassis on Jaguar XKEs, as well as chalking up 27 Tour de France victories.

Interesting note: According to Reynolds, the "proper" way to refer to the tubing is to call it "Five-Three-One" -- not "Five Thirty One" or "Five Hundred Thirty One." (The Custom Bicycle, Kolin and de la Rosa, 1979) Now you know.

According to Classic Rendezvous,
Schwinn felt the wording on
the 531 label was misleading
 (only the main tubes are
 "butted," the stays and fork
blades are "tapered") so this
version of the 531 label
was used on Paramounts
Proponents of 531 claim that its real benefit is that it maintains more of its strength after heating, thereby building a stronger frame. Some people describe it as "forgiving," and so in the huge factories that were cranking out large numbers of bikes -- like Raleigh, Peugeot, and others -- the frames were still strong even if the attention to detail and care against overheating the tubing were lacking. In the hands of a skilled builder, there should be no question about frame integrity.

There were many variations in tube sets available in 531 -- such as DB, SL, Competition, Professional, ST, and more (and some of the names/designations changed over the years, so forgive me for not getting more specific!) -- all with different specifications or wall thicknesses to cater to particular applications -- whether general racing, time-trialling, touring, or even for tandems.

Reynolds was such a presence in France that
special French-language decals were made.
Without a doubt, Reynolds dominated the British frame building market. It would be difficult to find a British builder who used anything else (For those still building today, that is still true). In fact, for a long time, one could expand that Reynolds dominance out to most of the English-speaking world. Chicago-built Schwinn Paramounts, for example, used Reynolds exclusively. Reynolds also had a huge presence in France, despite the fact that there were several French producers of high quality bicycle tubing. Many French bicycle companies like Peugeot, Gitane, Motobecane, and others used Reynolds in their top models, and many of the great French constructeurs used it as well. While Italian builders generally preferred Columbus tubing, there were some -- Masi, Pogliaghi, Legnano, Frejus, and even some earlier Cinellis -- that used 531.

Another big development in Reynolds history was the introduction of 753 in 1975. This was a special heat-treated version of 531, which yielded much higher strength and allowed remarkably thinner-walled tubing -- only .3 mm in the center section! The claims by Reynolds were that it could save as much as 1 to 1-1/2 pounds over 531 (depending on the version). But to preserve the tubing's strength during frame building, it had to be constructed only with low-temperature silver brazing, and the necessary tolerances were so close that a builder had to be specially certified by Reynolds in order to use it. Not only that, but the tubing was so stiff that it could not be cold set after brazing -- which meant that the frame's alignment had to be perfect from the start. The certification process involved building a sample frame and sending it to Reynolds for destructive testing. Apparently, about one-half of those applicants seeking certification were denied (VeloNews 1983).

The dominance of Reynolds tubing started to fade some time in the 1970s. While most British builders continued to use Reynolds, Columbus tubing from Italy made huge market gains by the end of the decade, especially on racing bikes, and especially in the U.S. There is no one definitive answer for how or why that happened, but there are a few possibilities -- some of which were provided to me by members of the Classic Rendezvous group. Funny thing, I was told by more than one CR list member that asking about Columbus vs. Reynolds was opening a can of worms. That certainly was not my intent. Of course, there will be people who take sides and try to argue one is better than the other -- but I'm not interested in those kinds of comparisons. I simply wanted to figure out what led to the shift, and it seems there's no simple answer.

A big part of it was probably due to perceptions and fashions. Italy really dominated trends in racing bikes, and most of the Italian bikes coming into the U.S. were built with Columbus. Buyers in the US, seeing all those gorgeous Colnagos, De Rosas, Pinarellos, Guerciottis and more -- all with that little white Columbus dove decal on the seat tube -- couldn't help but associate the brand with great racing bikes. Racing legends like Eddy Merckx were riding on Columbus-tubed bikes, and that certainly helped the image too. The Columbo family eventually purchased Cinelli (no more Reynolds-framed Cinellis! -- although Cinellis were being being built with Columbus by that time anyhow) which meant that they also had the whole Cinelli lug business and a close relationship with Campagnolo -- and those factors may have played a role, too.

But as evidence of the change, note that when Schwinn moved Paramount frame production from Chicago to Waterford, Wisconsin, they also switched from Reynolds to Columbus. That was probably a big blow to Reynolds. Another builder I'll mention is Dave Moulton, who built almost exclusively with Reynolds when he was living and working in England. But when he moved his frame building operation to the U.S. at the start of the 80s, he switched to Columbus -- not because he felt it was better, but because it was what his buyers expected/demanded in a high-end bicycle frame.

So moving on, what happened? Where does the story go from there? The heat-treated 753, as great as it was, never gained huge success, being so exclusive and difficult to work with. And 531 suffered from one "flaw" that kept it from continuing its success in the current bicycle marketplace: It really is not recommended for welding -- and that is how most frames are built today.

There are several developments from Reynolds to answer the weldability issue. There are newer "air-hardening" formulations that stand up to welding -- like 631 which Reynolds claims is the direct descendent of 531, and heat-treated 853, which is supposed to have the benefits of 753, with even more strength, and without the need for special frame-builders' certification. There are also the 525 chrome-moly and its heat-treated cousin 725 -- which are claimed by Reynolds to have a lot of the characteristics of 531 and 753, but again can be welded. The newest additions to the family are 953 and 931 stainless steel tube sets that have tensile strength well in excess of 753. It blows titanium away.

One final note in the Reynolds history is that it has gone through some major ownership changes in recent decades. By the 1970s, Reynolds (by this time, called TI Reynolds) owned Raleigh and most of the British cycle industry, including Sturmey-Archer and Brooks Saddles. In 1996, the company was taken over by Boulder, Colorado-based Coyote Sports. Coyote then filed for bankruptcy in 1999, most of the companies were sold off to investors, and in the following year a group of Reynolds managers purchased the tubing company from within, returning its base to England. The company is currently called Reynolds Technology Ltd. and has interests in a number of sectors outside of the bicycle industry, including motorsports and even oil drilling. In 2008, a special limited edition of classic 531 bicycle frame tubing was released. As I understand it, it is all gone now.

Despite all the developments and changes in bicycle tubing, there are a lot of people who still cherish the classic Reynolds 531. I still have a soft spot for it myself, and have several bikes that were built with it. For Retrogrouches like me, that little "Guaranteed Built With Reynolds 531" sticker just defines an era.


  1. Thanks for all the info. This is the kind of thing we will be tested on before we can pedal through the Pearly Gates.

  2. Thank you for the nice article. I've not been to your blog before, but I'll check out your other postings.

    But there is one very common error. 753 is not stiffer than 531 or any other carbon steel. Yield strength is greater, so you can bend it further and have it spring back. But all steels have the same Young's Modulus (AKA Modulus of Elasticity) Because of their generally thinner walls, 753 tubes are usually less stiff, but may buckle before you can bend them far enough to take a set.

    Even some of Reynolds literature, written no doubt by some marketing type, not an engineer, repeats this common misconception.

    You can build a lighter yet stiffer frame using higher strength steels by making larger diameter tubes with thinner walls. Lesser steels would dent too easily if drawn to such dimensions.

    Mark Stonich

    1. Thanks for the comment, Mark. I based that statement on not only the VeloNews article from '83 which I cited, but also from the comments of some 753-certified frame builders in the Kolin and de la Rosa book, The Custom Bicycle. What can I say, I took it at face value. Thanks for visiting the site!

    2. As I said it's VERY common misconception.

      It's funny, because the emphasis on stiffness is marketing driven, while there is no evidence it makes you faster. Good to have stiffness for control in an all out sprint or when carrying a heavy load. But many of us believe a supple frame is more efficient.

  3. Did I miss it or what does the number system - 531, 753, etc. -- refer to, indicate or come from?

    1. 4th paragraph -- 531 refers to the alloying metals and their proportions. 5 parts manganese, 3 parts carbon, 1 part molybdenum.

    2. I knew it must have been in there somewhere. and yet, quick-reading it once and then scanning it again (though clearly not closely enough), I missed the reference..

      Maybe in this case it would be worth tossing Style aside and being more graphic in the text. So, as per your reply: "The 531 name is a reference to the metallurgical components of the tubing - 5 parts manganese, 3 parts carbon, 1 part molybdenum."

      That I expect would tie the lazy/casual reader's eye in more easily..

  4. "953 and 931 .....blows titanium away."
    Says who? based on what?

    1. Based on tensile strength. 531 has tensile strength numbers of roughly 700 - 900 MPa. Heat treated 753 has tensile strength of roughly 1000 - 1200 MPa. 6Al-4V Titanium is 900 - 1150. 953 stainless steel is about 1750 - 2050.

  5. Brooks,
    Your numbers only tell half the story. Assuming the middle of the strength ranges you quote from Reynolds' site then 6Al-4V is only 54% as strong but it's also only 57% as heavy. So only a slight win for 953. Easily negated by the fact that you can make a larger diameter tube for the same weight of the Ti.

    So I looked at stiffness. There is some minor variation in the Modulus of Elasticity of alloy steels as the alloying elements themselves have different stiffness. Stainless steels vary a bit more and are a bit less stiff than Chro-Moly steels. I don't have a figure for 953 but Ti is 53% to 55% as stiff as the various stainless steels I could find a modulus for.

    So, on a pound for pound basis, it's hard to make the case that 953 "blows titanium away".

    The two are close enough that the skill of the fabricator is likely a bigger factor.

  6. A nice discussion of the main component of most classic bikes. There are other steels, of course, but the basic information is good - you want a substance that is strong yet has some "give". Anyone switching between an alloy road bike and a steel frame road bike would feel the difference. In my opinion, alloy frames "buzz". They are so stiff they transmit all the road surface variations too directly. I find it annoying, but I agree you can get a good ride at a good price with a modern alloy frame.

    Knowing the English (and the history of the industry here) as well as I do, I suspect they got a bit complacent with their local-market success and ignored exports, leaving it to other to take advantage. It seemed the British bike industry was always boom or bust.

    I do like 531. I have one 531c frame (not built up) that is amazing light. I'm almost afraid to touch it. I've a recent hand-built 631 frame (24.5") that I can see (let alone feel) the bottom bracket move when I stand on the pedals. That's a bit too much, and reminds me why Reynolds 501 (not mentioned above) was a good option for the larger rider. It also gives a pleasing ride, but is heavier.

    I've two titanium bikes - one bought built up and then upgraded - made in Taiwan. Excellent workmanship and alignment - fantastic value. One of my favourite rides. The other was built up from a frame I bought second-hand (never used) which turned out to be of Russian origin. I don't know much beyond what claimed on the stickers (3AL-2.5V) but it rides well and has become my all-round bad weather ride. To my senses, a titanium frame is just a bit stiffer than 531.

    I've got a few Columbus-tubed bikes (Colnago, Bianchi) and of course the quality of steel used varies. In some cases, the steel is a proprietary brand of Columbus (for F. Moser or Coppi) and it's a bit difficult to make any direct comparisons - of course they all ride well enough. I even have one mystery frame, hand built in Cape Town, with the "fluted" tubing used on some Colnagos (Gilco, I think). Pretty and rides very well. Then there are the Japanese...

    I've just brazed up my first 853 frame. It's still off at the painters, so we'll see how it "shakes out" but I'm guessing it will be good. It's a large-clearance touring frame, so I'm not expecting it to leap about like the Ti frames. But we specced it up using oversized tubes for strength so while it has the classic shape it is more rigid than you'd achieve with standard size tubing.

    1. Obviously I'm a huge fan of steel, but you mention titanium. I feel like titanium is a good choice for bicycles -- a good mix of strength, stiffness, and weight, and super longevity. For me, though, the only drawback is purely aesthetic -- I just can't get excited about welds -- I love the look of a nicely lugged frame. I know that an expertly welded frame has a lot going for it, and some people even like the "industrial" looking quality. I simply prefer the look of lugs. But you won't hear me gripe about titanium the way I do about carbon fiber.

  7. this stuff is great. thanks

  8. For what it's worth, you can purchase a Pashley Clubman made of traditional lugged and brazed 531 Reynolds tubing with investment cast lugs. I believe here in the states, it can be ordered from Universales Cycles

  9. the discussion about strength is moot; once the tubes have been joined they will have a different strength right where the bending loads are liable to be highest. Brazing does different things vs welding and what happens varies quite a lot with the steel you are dealing with. Most forms of CrMo will become softer in the HAZ, and/or harder and much more brittle. Often you will see both things happen in a single weld HAZ. Most tubing manufacturers skate over this, but post-joining strengths are usually way down on 'as received values. Reynolds witter on about 'air hardening' etc and in truth there may be some cleverness in the microalloying in some of their steels but the reality is that the HAZ is utterly banjaxed vs the original state of the steel. IIRC the hardness data they present has the indents so far apart that in a TIG weld HAZ you could miss a narrow zone that is either much harder or softer...
    931 looks brilliant until you heat it up, and then it suffers badly. I have seen several 931 frames crack in the HAZ. Same goes for other similar steels from other manufacturers.
    Arguably the approach taken with 753 was (is) the correct one; if brazed correctly it retains a high proportion of its pre-joining strength and doesn't appear to be made unduly brittle or anything. Similar benefits can (of course) be had in 531 and 653 tubing if that is silver brazed (at low temperatures)too, BTW.


  10. Any info on Reynolds 531 Special Lightweight (SL) tubing? I have an 80's Super Mondia that has 531 SL Decals on the frame. Bought new from PA Bikes long ago (don't recall when). Nice light, responsive bike. Very stiff, yet comfy ride. Top tube 26.6 - Down 28.36 - Seat 28.17 Best I could uow/ on my digital caliper. Thx

  11. I built an Ultegra bike based around a 531 SL Kalkhoff professional frame. the frame weight is Frame 3.69 lbs or 1675 gm very light but it is a 51 cm small
    Fork 1.33 lbs or 603 gm.
    Total bike weight is 21 lbs including saddle and pedals. I weigh 190 lbs and frame is plenty strong, not much flex. Ride is good but still fairly stiff. I have an old Carlton Corsair that has more compliant ride, but weights about 27 lbs. I also ride a Zurich 853. About same weight as Kalkoff and similar ride. Nothing beats the Carlton, but it is a bit heavy.