Ottrott Tubing Fatigue Over Time??

[Sandy]

I own 2 bikes, one a Serotta CSi and one a Serotta Ottrott ST. There have been debates within the forum in the past about whether steel bicycles fatigue. Some have said that if steel bikes do fatigue, it will occur at a rate that is so slow that the rider will be gone before the bike fatigues. Others say that the fatiguing can occur much faster. Others have said that steel bikes will not fatigue. Most have said that titanium bikes will simply not fatigue and will ride the same in 30 years as they ride now.

I recently spoke to someone who I would consider extremely knowledgeable in the field, and he said that ALL metals fatigue, varying with the metals, cycles, and application of the metal.

Now the Ottrott ST with the ST rear uses both a lot of titanium and carbon fiber. I had a Specialized Allez Epic carbon fiber bike before my first Serotta. I certainly believed that I fatigued that frame. Of course, the older carbon framed bikes were not as advanced as the newer ones.

The Ottrott uses carbon fiber in both the down tube and the top tube, and I believe that Serotta has performed tests, indicating that the Ottrott outperforms the CSi in the number of repetitions of pedal revolutions before there is failure. I am certainly not sure of precisely what testing was done, nor what criteria were used.

I am not a little guy, as some of you know. Unfortunately my weight is now 220. I will never be a small cyclist. I feel confident that the titanium tubes will be very resistant to fatigue over time. But what about the carbon tubing? What about the joining of the carbon tubes to the titanium tubes, using titanium lugs?

I would appreciate any comments relative to my questions. I have found the Ottrott ST to be the finest riding bike that I ever tried, but one must remember that I am STill Serotta Sandy, so what do I know??

[Kevin]

Sandy,

Serotta guarantees the carbon for life. That is good enough for me.

Kevin

[Sandy]

But does that even apply to fatigue? Seems like that would be much harder to discern or measure than other types of tubing or frame failure.

Sandy

[Kevin]

Perhaps Serotta Alyson can answer the question. Maybe we should bring back the question of the week.

Kevin

[Sandy]

She won't talk to me anymore since I sent her 3 week old roses.


Sad Sandy

[Kevin]

Did she know that you took the roses from a cemetery?

Kevin

[va rider]

Sandy, just send your Ottrott to me and I will ride until it fatigues.....

There is alot of years of experience on this forum. Has anybody even heard of a frame fatiguing? I have only been riding for about 10 years and in have lived in 3 different states. I have never heard of a a rider complaining that their bike, no matter the material, has fatigued.

[Needs Help]

I had a Specialized Allez Epic carbon fiber bike before my first Serotta. I certainly believed that I fatigued that frame.

I have never heard of a a rider complaining that their bike, no matter the material, has fatigued.

[vaxn8r]

I'm skeptical about fatiguing a CF frame. Sandy, my honest guess is that you got stronger and more comfortable on that Specialized Epic, thus making it feel more whippy or whatever made it "feel" fatigued. That Specialized was not a stiff frame be any measure. Of course some of the older aluminum/CF bonded frames were...not good and failed. But that was because of poor design. CF typically fails because of mechanical damage to the tube or because of improper joining of tubes. This usually presents early on. If you got a bad one you'll know it soon.

If you can wear out your Ottrott you deserve a new one anyway. Better get busy. I've got about 27K miles on my OCLV without a problem and I'm working on wearing out my Tetra Pro.

[va rider]

okay, other than Sandy, I have never heard of a rider fatiguing a frame.

I stand/sit corrected.

[Needs Help]

Technical White Paper
Bicycle Frame Materials Comparison with a Focus on Carbon Fiber Construction Methods

Presented by Craig Calfee and David Kelly
Originally presented in 7/94, updated in 10/02
http://www.calfeedesign.com/Calfee_TWP.pdf

-----
Steel, aluminum, titanium and carbon fiber all attempt to achieve the above criteria(ed: for the ideal bicycle), but differ from each other in strength, stiffness,weight, fatigue resistance, corrosion, etc. For example using aluminum or titanium in the same tube dimensions as a traditional steel frame would reduce weight but would produce excessive flexibility. So non-ferrous metal frames typically have larger tube diameters than steel ones to gain rigidity. Metal frames usually do not fail due to a single catastrophic load but because of small, repeated stresses (called "fatigue"). Steel and titanium have defined minimum fatigue limits—if the stresses are smaller than these limits, these smaller forces generally don't shorten the fatigue life of the frame. Aluminum has no such specific endurance limit, so each stress cycle, however small, takes the material that much closer to fatigue failure. This sounds worse than it is, however. Designers realize this limitation and attempt to "over build" their frames for a lifetime of use.

The 6061 and 7000 series aluminum used in bike frames is roughly one-third as heavy as steel, one-third as stiff, and, at best, is about 80% as strong as the 4130 cro-moly steel used in most bike frames. Titanium is roughly two-thirds the weight of steel, one-half as stiff, and about 60 percent as strong as steel. The carbon fiber composite most used by bicycle manufacturers is less than one-quarter the weight of steel, but it is about as stiff (which makes it almost four times as stiff on a weight-to-weight basis), and it is roughly four times as strong in tension. Carbon fiber also has a better fatigue life than steel, titanium, or aluminum, and the resins typically used to bond the fibers offer extremely good vibration damping.
-------

Also, Serotta says that UV damage to carbon fiber is a problem and that they use special UV protectants. I know Calfee recommends at least SPF 30 for their frames. :)

[Kevin]

According to Calfee:

Carbon fiber also has a better fatigue life than steel, titanium, or aluminum, and the resins typically used to bond the fibers offer extremely good vibration damping.

Kevin

[Climb01742]

something tells me we'll fatigue of our frames before our frames fatigue of us.

but on a more serious note, pro racers would be a good test i think. i wonder how CF frames have held up for Look, Trek, Time and so on? i haven't heard or read of unusual fatigue rates. jerk, any insight there?

[zap]

Sandy,

many years ago when pro racers rode steel, they claimed that they could tell when a frame became "fatigued". Usually a steel frame would last one (1) year.

Of course if you rode a steel frame that used Excel's excellent tubing, it would probably last 2-3 years.

All materials today are superior to what was available even 10 years ago. Carbon is best with the only limiting factor being the epoxy. Titanium does last a long time as well. But so do some of the modern aluminum alloys.

I have an excellent article from a German magazine that tested a wide variety of frames and materials. You can come by some time to review the stats.

Bottom line, according to this article, design and craftsmanship are more important elements to longevity than material choice. Some of the aluminum frames lasted much longer than some of the highly regarding titanium frames. Ummm, a Cannondale frame out lasted the Merlin Extralite by a huge margin. Actually they stopped the testing Cannondale after 200,000 cycles and it was still going strong. Another surprise, tested steel frames on average were the worst!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Needs Help]

Konnen Sie ein translation geposted? :)

[Dr. Doofus]

The Doc Says:

1) Weight. Ok, if you really are riding a beer can, you body weight will significantly fatigue the frame, as soon as you sit on it. However, body weight isn't much of an issue for a custom-made frame (or for most high-end production frames...) becuase...

2) Its not weight, its watts. A 145-pound pro puts more strain on a frame in one year than a 190-pound recreational rider (who rarely cracks the 25mph barrier) does in five. Not scientific, so don't get techno-weenie slide rule out on the doc, but you get the point. Rolling around chatting at 170-200 watts doesn't put much stress on a frame, even if you weigh 200 pounds. Putting the 500-watt smackdown on the Bosberg for the third time in a month does. So...

3) Unless one is riding a 2.5 pound aluminum (or scandium especially) frame, you're not going to fatigue it anytime within the next ten years, unless you have no job and you log 800 hours on the bike each year, plus racing, in which case you better be riding free bikes *or* you better do a reality check, becuase if you're training that much and not gettng free crap, you suck and you should take up a second hobby along with riding your bike. Therefore...

4) The stuff this guy or that guy who builds bikes says is great to talk about after the ride or when you're constipated and sitting on the crapper looking at pictures of Johan and talking with your bike buddy (who doesn't know you're only talking to him to help you take a dump, because that works for some reason, but he won't be your buddy anymore if you tell him his only real purpose in your life is to be, in turns, laxative and wheel to suck) on the phone, but, as many before the Doc have said, you'll get tired of your bike before it gets tired of you. Which is why...

5) The Doc still wants that Mercian. Obsolete, non-gourmet, but the Doc digs them like he digs Dodge Darts, which are sort of their bike equivalent...or maybe a badass Vauxhall, as much as that's possible....

[Andreu]

There is alot of years of experience on this forum. Has anybody even heard of a frame fatiguing? I have only been riding for about 10 years and in have lived in 3 different states. I have never heard of a a rider complaining that their bike, no matter the material, has fatigued.

Same here. Never heard of it.
Maybe the molecular or atomic (or whatever :confused: ) structure of the metal does change with time but I have never experienced this with steel (I only have about 15 years experience of riding and racing). I know plenty of guys who ride aluminium, carbon etc and I have never heard them complain. Maybe its too small to detect or we change our bikes before it gets to a stage when we can detect it.
I suspect that my legs are fatuiging faster than any frame that Serotta or any other company can build.
A :bike:

[sam235813]

Someone once told me that the average first-rate bike is designed to last between 25,000 and 35,000 miles. He feels that most manufacturers shoot for this regardless of material (save for carbon). If you ride 10 miles a day for 350 days out of the year, your bike should last you about 8-10 years. I know very few serious cyclists who hold on to their bikes for more than 5 years regardless of condition. Commitment to a frame, therefore, seems far shorter than the potential life span of the frame. So, he suggested that I simply not worry and enjoy the ride.

His closing question to me (which was in response to my continuing interrogation) was "OK, fine, when was the last time _you_ broke a frame?" Sage words indeed...

--Sam

[Big Dan]

I read David Tesch (the late bike builder) said that the best way to deal with frame fatigue was buying more bikes. In that way you won't use one up....

Sandy time to order another Serotta.............. :banana:

[Kevan]

Thanks Pal.

[mikemets]

...who's manning the grill?

[Kevan]

until after the sheepskins been doled out. Nothing like attending a highschool graduation when it's 95 degrees and we're under a tent on the athletic field. Thinking Bermuda shorts and Knee-highs might be a fashion risk, but the thought of wearing a suit... well, that's just plain'o murder.

When I get home, I'm takin' orders!

[wasfast]

Also, Serotta says that UV damage to carbon fiber is a problem and that they use special UV protectants. I know Calfee recommends at least SPF 30 for their frames. :)

Virtually any quality clear coat (automotive finishes) will provide UV filtering. I'm talking polyurethane, polyester etc, not lacquer.

Ever notice how all the sunglasses say they are "specially made to filter UV rays"? Polycarbonate filters the UV spectrum even in the clear. It's a property of the raw material.

[shaq-d]

His closing question to me (which was in response to my continuing interrogation) was "OK, fine, when was the last time _you_ broke a frame?"

3 days ago. crashed out my pinarello 1983-or-so. wheels and components all intact. _Down tube_ screwed, dented on both sides it looks like it was hammered up and in, even though the fork didn't hit it. good times.

so: columbus SL 1983 steel that's been used in all kinds of weather and conditions, can fail. in a crash. heh.

sd

[dirtdigger88]

:no:

Jason

[Skrawny]

I was wondering about this recently. The Discovery team had some prototype Trek bikes out on Paris-Roubaix which had CF chainstays and an elasomer shock in the seatstay (wishbone). The shock apparently had about 17mm of travel. Made me wonder how many cobbles one could ride over before the chainstays failed...
-s

[dirtdigger88]

Cannondale Scapel (http://www.cannondale.com/bikes/05/cusa/model-5VP3.html)

these bikes have nearly 3 inches of travel using a carbon fiber chain stay and no pivot

Jason

[Serpico]

I was wondering about this recently. The Discovery team had some prototype Trek bikes out on Paris-Roubaix which had CF chainstays and an elasomer shock in the seatstay (wishbone). The shock apparently had about 17mm of travel. Made me wonder how many cobbles one could ride over before the chainstays failed...
-s

take a look at Klein's SPA suspension on the Reve, same stuff

not sure if it's chainstays they are worried about, or increased rider fatigue due to vibration/impact

[Serpico]

Cannondale Scapel (http://www.cannondale.com/bikes/05/cusa/model-5VP3.html)

these bikes have nearly 3 inches of travel using a carbon fiber chain stay and no pivot

Jason

since you mentioned this I have a related question. How does this (below) work? Competitivecyclist says it's an scandium/aluminum frame with pivotless 1" suspension. I always thought bending aluminum, even an inch, was bad.

[dirtdigger88]

I have never seen these before you posted so take this with a grain of salt- but the stays are not aluminum- they are scandium- so what ever the properties of that metal are- I am guessing they dont break like aluminum-

other than that I dont know

Jason

http://www.eastonbike.com/downloadable_files/fab_instr/fab_instructions-sc.pdf

read what easton says about scandium- at the end the comment about its excellent fatigue life

[jl123]

I think John Castellano of Ibis Silk-ti fame, invented the above design; whereby chainstays are made flat so as to allow for a good deal of pivotless travel at the rear-when combined with a shock-elastomer or air. Castellano is now getting back into the act, and making a silk-ti for the road like the Klien Reve with about .5 to 1 inch of rear travel.

I truly wonder if the suspension on these rigs will work better, than for instance the simplest systems such as Moots Vamoots Ybb? I've got to believe that with such great designers and cad programs, that such systems will improve and actually work exactly when bumps occur and not work when the road is smooth. Note, some of these designs once dialed in may eventually surpass Serotta's systems- I mean a controlled suspension once perfected on any passive wheeled machine has got to work better than the inherent spring of a lever- especially when a bit more suspension travel is called for. And thats my hypothosis, that indeed .5 to 1 inch of travel can at times be useful to a road rider. I think we will be seeing a huge increase in the number of rear suspension road bikes made in the next 2 or 3 years; because they really can work. Hint to Serotta, get back into the suspension game to stay competitive in the riding for recreation market. Just my opinion.

[Darrell]

man

I have an excellent article from a German magazine that tested a wide variety of frames and materials. You can come by some time to review the stats.

Another surprise, tested steel frames on average were the worst!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The articale in question has a few flaws, one major one is that they tested steel frames that were built using steel tubes that made their first appearance in 1977. The metallurgy of the tested frames is now approaching 30 years old.
One must ask why they performed the tests on old frames that used tubes that were no longer in production for 10 to 15 years. I did ask the question and recieved no reply. {Circa 2001}
Lets test a 1977 titanium Speedwell next to 2005 titanium frames and see the results.

[zap]

Darrel, are you referring to the article floating around the internet?

The article I referred to last year (never did see this one on the web) is a bit old (mid 90's) and featured steel such as Serotta's CSI & frames built with Columbus EL-OS & Genius OS. From what I recall, the steel frames (including Columbus EL-OS) that failed quite quickly probably failed due to poor craftsmanship. I believe this is true for any bicycle frame made from other materials as well.

[pdonk]

I think John Castellano of Ibis Silk-ti fame, invented the above design; whereby chainstays are made flat so as to allow for a good deal of pivotless travel at the rear-when combined with a shock-elastomer or air.


Here is a link to his site and the pics from FEA to show how it works.

http://www.castellanodesigns.com/tech.html

[Tom]

All I know is my legs are carbon based and they fatigue real quick. They wouldn't fatigue nearly as fast if they were metal, I am sure.

And this post is, my friends, if not the most useless contribution today must definitely be on the podium.

[davep]

Cannondale Scapel (http://www.cannondale.com/bikes/05/cusa/model-5VP3.html)

these bikes have nearly 3 inches of travel using a carbon fiber chain stay and no pivot

Jason

Jason,

In the interest of accuracy, on the page you have referenced above, it states:

"The Scalpel’s pivot is located at a precise point on its carbon fiber chainstays, dictated by the stays’ shape and the lay-up of the fibers."

[dirtdigger88]

Jason,

In the interest of accuracy, on the page you have referenced above, it states:

"The Scalpel’s pivot is located at a precise point on its carbon fiber chainstays, dictated by the stays’ shape and the lay-up of the fibers."

it is a virtual pivot though- picture an intended point where the carbon chainstay bends but there is not a pivoit with a bearing like say a full suspension MTB- look at the picture the stays bend where the stays get thin at the mid point- so the carbon is flexing up and down like a diving board with no piviot

Jason

[dirtdigger88]

as apposed to the specialize (or any 4 bar suspension) with an acutal piviot-

jason

[dirtdigger88]

http://www.cannondale.com/bikes/innovation/scalpel/

follow this link- there is a button on the left side at the top that will show how the suspension works- so yes there is a piviot "point" but no acutal piviot or maybe it would be better if I said no bearing

Jason

[Darrell]

Darrel, are you referring to the article floating around the internet?

The article I referred to last year (never did see this one on the web) is a bit old (mid 90's) and featured steel such as Serotta's CSI & frames built with Columbus EL-OS & Genius OS. From what I recall, the steel frames (including Columbus EL-OS) that failed quite quickly probably failed due to poor craftsmanship. I believe this is true for any bicycle frame made from other materials as well.

Nope, the one you refer to is one I have not seen.
I would like to have a look? Links?