'recent' and 'reynolds 531' in the same phrase?? Reynolds 531 dates back to the late 60s if not earlier. Thats pretty much ancient history in bicycle technology terms.

Reynolds 531 was introduced in 1935 and was used in WW2 British fighters, specifically the Supermarine Spitfire and ther Hawker Hurricane.

You're completely missing the point. Strength isn't the issue; failure mode is.

Ancient, in bicycle terminology for me, at least, dates back to before the Wright boys
put that flying machine together in the back of that bike shop of theirs.

I think you understand my point, that airplanes originally borrowed from bikes and
that after the big money started chasing altitude, bikes have gotten considerable tech
boost from the aerospace industry.

And I was born in 1949, sonny Jim, so don't tell me how ancient the 60's were, cause I was there.

How long is an ear? What is a whole now?

I have sweaters that are older than your bicycle, Bubba. But hey, you win the internet on this one.

hey, I'm only 5 years behind you, and I remember the 60s kinda-sorta, even if I was a bit too young for the best of it.

This thread is all making it quite clear to me...

Here are my findings:

Steel... The unsinkable Titanic was made of steel...it sank because of ice and water.

Carbon Fiber... As said in a previous posts some Airbus plane crashed because of it.

Aluminum... In the cosntruction industrty, aluminum ladders are used daily. Their failure rates have led to deaths among thousands of workers.

Lead... Acute lead poisoning from a gun or just regular lead poisoning from licking paint.

So... I propose we start building framesets out of Tightbond III glue (because it's waterproof) and popsicle sticks. I assume this is by far the most safe material on the planet to build anything. Kids eat popsicles (they love them) and kids eat glue (they love it too) but we (the popsicle and glue eaters) have all grown up just fine! I will be working on a prototype and a patent!!!

The one absolute proof that you were there is the vagueness of your recollections of the period.

Bamboo..........several billion Asians have enough building and design experience
that it is now the trendy frame material of choice.

............Save the whales with bamboo bikes !

Now that is funny!

Did I mention I lived IN San Francisco in the 60s?

I was riding a bike in 1949. Now I ride 2 road bikes, both have carbon fiber frames, forks, and steer tubes.
Rode 4706 miles in 2012 before the flu stopped me.

I'll lift my glass to that.. CONGRATS! Beat me my 600 miles... albeit I missed 3+ weeks with a bad cold.

GENTELMAN's: Tone of this thread is heading far south.. c'mon. Reminds me of an old tale I heard living in the sandhills of NE back when. Couple of bar flies get a load of brew onboard... go behind the establishment.. and see who can whiz into the strong north wind w/o getting their jeans wet. Give it some rest.............

Anybody know someone who works at a LBS who has to replace the recall forks? What I wonder.. what's the main problem/s with why their recalled? Those recalls more a function of rate of manufacture.. or design?

Some frames are made from magnesium or alloys with magnesium in them.Magnesium is very flammable so I won't ride them due to the risk I 'd catch fire....what was this thread about again? Oh nevermind.

That's sort of true. It's only flamable in powder or shavings...not frames or blocks.

This reminds me of all the old stories of why a VW engine catches fire so easy...I am sure it had nothing to do with plastic fule filters and pumping gasoline into a into the engine compartment!

Being tandem riders and having pedaled over 230,000 miles on tandem bicycles since 1975 we have had only one bad experience with a fork.
It was steel (Reynolds custom 531) and broke/failed at 13,000 miles.
Together we tip the scales at 238 lbs so we are right in your weight category.
Currently have 34,000 miles on carbon fiber (Alpha Q) fork on our full carbon fiber tandem.
Have also broken 2 steel tandem frames. One break at 50,000 miles and the other at 56,000 miles.
Have ridden steel alloys, aluminum, titanium, carbon fiber and bamboo bicycles.
Amy material will eventually fagtigue/fail/break.

Bold mine.

That is rare.. very. Unless one gets said slug shot into them... the kind of instant 'lead posioning' that kills.. slug's effect. Sometimes slugs are left inside a body.. with no apparent ill effects. I know of the old timers who shot tons of lead bullets in an ENCLOSED environment.. and they all tested LOW for lead levels.

One has be completely ignorant and careless to get real lead levels up.. like in the 2nd case mentioned.

Ok Very basic Chemistry fans,


Mg, is diffrernt from Mn, and Mo.

atomic #s 12, 25 & 42 1 each in Period row, row 2, 3 & 4

as I recall Reynolds 531 alloy is C, Mn, Mo, in of course, Fe.

The phrase acute lead poisoning doesn't refer to a toxic event. It's a play on words referring to being shot, ie. infused with lead and suffering immediate ill effects or death.

In any case metallic lead is rarely toxic. It's various oxides and organic compounds of lead that toxic. If lead is left in the body, it tends to become encapsulated and not dissolve into tissues or the bloodstream. Generally lead poisoning is a slow chronic process as small doses accumulate in the body. You can do this ingesting lead shot, but the more likely causes are lead dust, or ingestion of lead oxides. Dust is a problem because the small particle size is easy to inhale and the increased surface area makes for rapid oxidation.

An interesting occupational lead risk is to dive shop employees. The constant stacking and banging of lead dive weights flakes the surface oxide into fine dust which is then inhaled.

That's the thing - titanium and steel (and alloys thereof), do not fail due to fatigue if the stresses are kept low enough, unlike aluminium and magnesium (and alloys thereof), which will eventually fail by fatigue regardless of the magnitude of the stresses.

Magnesium, manganese and molybdenum.

And all three are used in bikes - 531 is a manganese-molybdenum alloy steel, 4130 is chromium-molybdenum alloy steel, and magnesium alloys have been used for bike frames, so it's no wonder the names are getting hurled about.

But that's a bit like saying to a weight lifter that he will never injure himself as long as he doesn't lift more than X amount of weight. Obviously steel and ti are very good frame materials, as are others, but the "no fatigue limit" characteristic of those materials is obviously only a part of the equation, because steel and ti frames do fail from fatigue sometimes.

I was told by my materials lecturer (I'm a first-year mechanical engineering student) that a lot of structures aren't designed to always keep the stresses below the fatigue limit, because they'd be quite a bit heavier if they were. I'm not sure traditional steel frames and forks are "designed" in that sense anyway, but if I was designing a fork that I was going to be riding, I might put up with a bit of excess weight in order to keep the stress below the fatigue limit for a decent proportion of the time. I don't know if that's actually how manufacturers do it, though.

I think you've hit on a key point in mentioning weight concerns and restraints.

Me too, but given the typical endurance limit for steel 10^7 to 10^8 how much riding would it take to stress a fork beyond the fatigue limit that many times? The fatigue limit for steel is roughly around half of its tensile strength right? (I'm not in a materials class, so seriously.) If that's right then it takes pretty big jar to pass that limit. Doing that 10 million times I think you'd have to be riding rough trail really hard, eight hours every day, for ten years. So it's not really a factor we'd need to worry about much imo, for steel.