Look equipment failure

I assume the handlebars were CF? If so there's the problem! CF is very particular about having the right amount of torque applied or it will crush the fibers if too much clamping force is applied which will lead to eventual failure. Look won't guarantee that sort of the thing because they will blame the error on whoever installed the bars...and they would be right, also the bars are not generally made by the bike manufacture, they could be TTT bars or some other brand and thus the bar manufacture is the one to be blamed. The bike arrives at the dealer with a lot of stuff to be installed and the bars is one of those items, so the dealer is suppose to install the bars according to the manufacture of the bar recommended torque, if the the dealer can prove they installed them correctly and the bar was flawed then the problem would be on the bar manufacture.

Trying to get anyone to stand behind their product is like trying to pull teeth out of your own head! I had an Orbea Scandium bike that cracked the top of the headtube after only 8,000 miles, Orbea called it fatigue and bowed out of their warranty!! I could have obtained an attorney but my attorney said the legal fees plus expert testimony on how and why the headtube cracked would cost more than the bike was worth to try to fight it.

Look does its own carbon. From the manufacturing of the weave, itself, to the layup.

https://roadbikeaction.com/features/rba-features/being-there-inside-the-look-factory

https://roadcyclinguk.com/news/look-factory-visit-photo-gallery.html

https://www.lookcycle.com/en/technologies/carbon-technology/

Regardless of the material...I have snapped a Campagnolo Super Record alloy crank arm into two pieces. Other riders have done likewise and no brand is exempt from having had many aluminum cranks break.

For that matter, there's a website featuring a boat load of pics of snapped steel crank spindles from various manufacturers.

As far as alloy bars go, I've known two guys to snap them. One was a Sakae, I'm pretty sure. It was on a tandem and how he got it stopped without crashing is story we still re-tell to this very day. Steering and braking a fast tandem with half a handlebar!

The other guy went down, like Yojimbo did. I can't remember the specifics of his injuries, but he had a lot of road rash.

Time bicycles, the other French carbon fiber manufacturer, also manufactures its own carbon weave and pre-preg.

Yojimbo, any more details of what happened? Bar material? Rider weight and power? History of the bike? Riding style? Monocoque bar-stem aero combination? Did the steerer tube, stem, bar or bar/stem one-piece combo snap?

OP here.

It snapped off at the steerer tube. My theory is that it was overtightened and over time the carbon failed. There was just enough time to think "Oh [censored]" before I hit the road.

I'm not a heavy guy...165 lbs at the time of crash. I ride, including commuting, maybe 6000 km a year. It gets cold here in Toronto else I would ride more. I'll be on the Sufferfest and Swift when it gets really cold.

In hindsight, I suppose there was some warning. The bars felt like they were flexing at times which was something new. I guess this was a crack in the steerer tube opening and closing - and then it finally reached the point of failure.

I obviously didn't think of this as a failure mode at all or I would have checked. The night before the crash I even redid the bar tape and adjusted the brake hood on one side - didn't notice anything was wrong.

10 weeks now - going to start some physio for the collarbone next week. Lost a lot of fitness - not that I had a lot to start with but I suffered a lot to get what I had.

I have to buy a new bike now. I'm thinking a Cervelo S2 with Ultegra (not the electronic version) with Kysrium Elite wheels. I had those Ksyriums on my Look and they seemed pretty good. The black S2 frame looks pretty cool to me.

I've been hit by cars 3 times, broken 3 helmets over the years, broken my femur, had a few crashes with nothing broken, and like everyone else, so many close calls I can't even remember them. I've never been afraid to ride before but I am after this. Cars and rain are one thing, but structural failure of the bicycle is something else.

Safe riding to everyone who reads this. And check your bike

I guess you're talking about that one piece stem and handlebar combination. I've been warning people away from those for some time. ALL of these carbon fiber parts have a learning curve and Look got into those far too early. They were built in multiple pieces slathered together and cost a small fortune. The same sort of bars built today from the Chinese cost 1/10th the price and are all built in one piece. They appear to me to be safe but you cannot have light and safe in the same sentence.

Here's some interesting info about the pros and cons of AL vs CF bars: http://www.colbypearce.com/handlebars-carbon-vs-aluminum/
And here's a break test done on AL and CF bars:

Of course that last one doesn't take into consideration if the CF bars were not torqued correctly.[/I]

Froze said:

Here's some interesting info about the pros and cons of AL vs CF bars: http://www.colbypearce.com/handlebars-carbon-vs-aluminum/
And here's a break test done on AL and CF bars:

Of course that last one doesn't take into consideration if the CF bars were not torqued correctly.[/I]

Raise your hand if you think even good bike mechanics use torque wrenches. And even if they do I have three torque wrenches that tighten to different values when turned to the same setting.

Interesting video. Of course the video isn't about all CF vs all AL bars, because it only compares two specific model handlebars from Controltech. The GCN narrator is really stretching when he tries to generalize the results to all CF vs AL bars. EG, if Controltech had a CF model that weighed as much as the AL one, what would the comparative results be? What about bars from different manufacturers?

I like the part at the end about building handlebars with essentially infinite fatigue life, where he states these would be too heavy and stiff for road bikes. Too heavy for whom? I'll gladly take bars and stems that weigh a 100g more to get unlimited fatigue life. Since I'm not a racer, and now weigh 30 lbs over my best race-weight, I'm not worried about saving a few hundred grams. I'd rather spend my money on strong stuff I don't have to worry about down the road.

So...it was the fork STEERER TUBE that failed and not the handlbars? Or did the BARS fail at the steerer clamp area?

Lots of fork steerer tubes have failed due to improper stem clamping force, not having the Expander plug located directly under the stem clamp's lower edge, improper exclusion of a spacer under the clamp in some cases (see manufacturer's specs).

There was a Look one piece bar and stem combination that would breaks right at the steering tube intersection. I've seen two of them - which were the only two I've ever seen since Look was asking more than $200 for that piece. They were made in the bar, the stem and a separate steering post clamp. This was made in a couple of pieces. The two I saw broke at the steering tube clamp. From talking to the people who had them they could see the cracks forming for months before they actually broke.

cyclintom, you apparently know a couple of brave cyclists. If I found any crack in my stem clamp, stem or bars, I'd be replacing them before the next ride. I have a lot of curiosity about the mechanics of fatigue failure, but not at the expense of becoming a crash-test dummy.

Meh. One of my Wilier's cracked are the right rear chainstay / dropout area where the tube and dropout were joined.It cracked and I continued riding it for a couple of weeks, keeping a close eye on it. It never got worse or failed and Wilier replaced the frameset under warranty.

Anybody here remember the infamous 'Modolo Death Stems' from the 1980's? The were aluminum and caused a bunch of crashes. Like Tom said, the Look bar/stem/clamp setup was probably just [censored] poor design and build quality.

I'm still waiting to hear from Yojimbo to find out if it was the one-piece bar that failed or the steerer tube.

"I guess this was a crack in the steerer tube opening and closing"

dhk2 said:

cyclintom, you apparently know a couple of brave cyclists. If I found any crack in my stem clamp, stem or bars, I'd be replacing them before the next ride. I have a lot of curiosity about the mechanics of fatigue failure, but not at the expense of becoming a crash-test dummy.

Remember that too many people equate expensive with reliable. These Look single bar combinations hadn't broken all the way through but were cracked between a couple of the colors that Look applied around the clamp area. They were not particularly noticeable except to someone that has had so many carbon parts break.

Again I'll repeat - I have been convinced by mechanical engineers that you can build reliable carbon fiber frames and forks and components. But they would have to be designed for reliability and the top end bikes are designed for minimal weight.

Totally agree. But remember metal frames and forks can also be designed to be ultralight with limited fatigue life. A few years ago, I recall the Cannondale manual clearly stated that their CAAD race bikes may only last for a season or two of hard racing and training, and that fatigue failures are normal for any ultralight equipment under hard use.

So the key to safe riding is to educate the user to practice a good inspection program. Carefully looking the bike over while cleaning, and being aware of any creaks or flexing. The major brands urge customers to bring the bike back for free inspection if anything is found, or any new noises or flexing is experienced. Doing so, the ultralight bikes can still be reliable and safe during their life, even if that lifetime is limited.

cyclintom said:

But they would have to be designed for reliability and the top end bikes are designed for minimal weight.

Define 'reliability'.

I'm honestly not trying to pick an argument, but...

They are designed for both. Top end bikes use the very strongest carbon fiber and can actually be stronger than heavier, less expensive models. The may suffer less abuse than a heavier frame or component, but in normal use even the sub-kilogram frames have been holding up to heavier riders, high Watt output riders and what I consider to be one of the devices known to break frames...the fixed mount turbo trainer. I can not think of a manufacturer out there right now that would deliberately sell any level of racing bike that wasn't safe and reliable. In error? Of course they have. And they generally correct their errors in spades as their reputation can't afford anything other than high marks. Brand loyalty isn't what it used to be...just sayin'.

Look clearly designed the part in a faulty manner or built it in a faulty manner...or both. 'IF', indeed, it was Tom's bars that failed and not the steerer tube as a result of the causes listed above. We'll see.

Zwift is full of guys putting $5,000-$10,000 bikes on $1,600 Tacx NEO's or Cyclops Hammer's and racing the daylights out them. The stresses imparted directly into a restrained set of ultralight tubing is insane and they seem, for the most part, to hold up to the abuse well.

Having broken a steel Colnago and snapped an alloy Campagnolo Super Record crank arm as well as the carbon Wilier, I can testify that all materials can and will break and science has proven carbon fiber to be the most fatigue resistant of all the traditional bike building materials. And my Douglas, being a very thin wall thickness 2006 vintage carbon frame has 25,000-30,000 very reliable miles on it...queue Froze and his million-mile old steel horse! LOL!

Now...drill a guardrail at 20 MPH with any of it and my guess is the trash dumpster will have a crumpled wheel made of (insert material of choice here) and / or a wrinkled-shattered-beer canned-severely deformed frame made of (insert material of choice here) in it.

dhk2 said:

Totally agree. But remember metal frames and forks can also be designed to be ultralight with limited fatigue life. A few years ago, I recall the Cannondale manual clearly stated that their CAAD race bikes may only last for a season or two of hard racing and training, and that fatigue failures are normal for any ultralight equipment under hard use.

So the key to safe riding is to educate the user to practice a good inspection program. Carefully looking the bike over while cleaning, and being aware of any creaks or flexing. The major brands urge customers to bring the bike back for free inspection if anything is found, or any new noises or flexing is experienced. Doing so, the ultralight bikes can still be reliable and safe during their life, even if that lifetime is limited.

And the older aluminum frames are still riding. After 25 years we are beginning to see the Cannondale early aluminum frames beginning to fail. Vitus and Alan's with 100,000 miles and more of them can still be raced with the best.

And they very rarely fail catastrophically. That is, it starts becoming hard to pedal, you stop and take a look and you can see the chainstay is broken. After they switched to aircraft aluminum they started building bikes almost as light as CF. These bikes are not showing signs of fatigue for the most part and again it is usually not catastrophic and most of the time after you find a failed frame part you can ride home.

Now the early Al bikes were really soft frames. The later aircraft Al were so stiff that they were a problem to ride.

CAMPYBOB said:

Define 'reliability'.

I'm honestly not trying to pick an argument, but...

They are designed for both. Top end bikes use the very strongest carbon fiber and can actually be stronger than heavier, less expensive models. The may suffer less abuse than a heavier frame or component, but in normal use even the sub-kilogram frames have been holding up to heavier riders, high Watt output riders and what I consider to be one of the devices known to break frames...the fixed mount turbo trainer. I can not think of a manufacturer out there right now that would deliberately sell any level of racing bike that wasn't safe and reliable. In error? Of course they have. And they generally correct their errors in spades as their reputation can't afford anything other than high marks. Brand loyalty isn't what it used to be...just sayin'.

Look clearly designed the part in a faulty manner or built it in a faulty manner...or both. 'IF', indeed, it was Tom's bars that failed and not the steerer tube as a result of the causes listed above. We'll see.

Zwift is full of guys putting $5,000-$10,000 bikes on $1,600 Tacx NEO's or Cyclops Hammer's and racing the daylights out them. The stresses imparted directly into a restrained set of ultralight tubing is insane and they seem, for the most part, to hold up to the abuse well.

Having broken a steel Colnago and snapped an alloy Campagnolo Super Record crank arm as well as the carbon Wilier, I can testify that all materials can and will break and science has proven carbon fiber to be the most fatigue resistant of all the traditional bike building materials. And my Douglas, being a very thin wall thickness 2006 vintage carbon frame has 25,000-30,000 very reliable miles on it...queue Froze and his million-mile old steel horse! LOL!

Now...drill a guardrail at 20 MPH with any of it and my guess is the trash dumpster will have a crumpled wheel made of (insert material of choice here) and / or a wrinkled-shattered-beer canned-severely deformed frame made of (insert material of choice here) in it.

There is absolutely no doubt that CF is stronger than steel and much lighter. But it is also much thinner. This along with extreme rigidity means that what would be some minor defect meaningless in another material grows huge. A bubble in the layup can cut the resin thickness in half greatly reducing the strength in that area. And there are a very large number of critical places in a bicycle frame and fork to have defects in or around.

Resin hardens to something like 90% of its finished strength (depending on type) in between a couple of hours and weeks. Bicycle frames usually harden in several hours under UV lamps I seem to recall.

So over the rest of the useful lifespan of the frames it continues to harden. Unfortunately it also continues to grow more and more brittle.

The old Treks and the like were so heavily built that it would take forever for the embrittlement to cause sufficient weakness to fail. But the newer and much thinner layups not only have the resin embrittlement problem but depending on the molding method can have focused forces - where a thick spot appears in the layup due to the inflatable mold having a bump or some such in it. This can focus the riding forces on either side of the heavier spot.

Now some of the manufacturers are not putting color in the resins so that the layup is transparent and errors are more easily identified. As time goes on they will grow more and more technical but as I said elsewhere - you cannot get "light" and "safe" into the same sentence.

I have outgrown my total distrust for CF but I won't personally use it again (though my aluminum Ridley has a CF fork)

Just a few thoughts to make you less nervous about riding a CF fork. Not trying to change your preference for material. I actually prefer metal frames over CF too, but not because CF is unsafe. OK, here goes:

Yes, CF can make designed to be very thin and light, but the same goes for steel. What you and I might say is "too thin, too light" is just what someone else wants to buy. High-tensile steel at 0.3mm wall thickness has to be manufactured to high quality standards and handled carefully to be strong and safe.

Degradation of CF due to heat, humidity and UV exposure is a concern for aircraft, but unless you have to store the bike outside in the sun, I wouldn't worry about it.

Good you are learning to trust CF. Anyone riding a CF fork needs to have trust in CF, the fork being critical to safety. I've seen a guy ride with a failed chainstay weld (on a cheap Fuji al frame) and barely notice, but having a fork leg separate is a whole different thing. The bending loads on forks are extreme (potholes, limit braking with 100% weight on the front wheel) yet high-quality CF forks have proven to be up to the job.

Not sure what you're talking about with the stiffness. Stiff and strong is good. Going to a high-tensile newer aluminum alloy such as 7075 T6 allows for triple-butted tubes to be made lighter and stiffer than 1950's era metal...that's good.
I've got a custom frame from 2003 made from Columbus Zonal megatubes with a CF rear triangle and Reynolds Ouzo Pro fork. I rode it for 13 years, 40K miles, including lots of hard climbing, with no evidence of any problems.

So, I'd say don't worry about your frame materials. Pay attention to any noises or flexing, inspect carefully after any big impacts, and go ride.

dhk2 said:

Just a few thoughts to make you less nervous about riding a CF fork. Not trying to change your preference for material. I actually prefer metal frames over CF too, but not because CF is unsafe. OK, here goes:

Yes, CF can make designed to be very thin and light, but the same goes for steel. What you and I might say is "too thin, too light" is just what someone else wants to buy. High-tensile steel at 0.3mm wall thickness has to be manufactured to high quality standards and handled carefully to be strong and safe.

Degradation of CF due to heat, humidity and UV exposure is a concern for aircraft, but unless you have to store the bike outside in the sun, I wouldn't worry about it.

Good you are learning to trust CF. Anyone riding a CF fork needs to have trust in CF, the fork being critical to safety. I've seen a guy ride with a failed chainstay weld (on a cheap Fuji al frame) and barely notice, but having a fork leg separate is a whole different thing. The bending loads on forks are extreme (potholes, limit braking with 100% weight on the front wheel) yet high-quality CF forks have proven to be up to the job.

Not sure what you're talking about with the stiffness. Stiff and strong is good. Going to a high-tensile newer aluminum alloy such as 7075 T6 allows for triple-butted tubes to be made lighter and stiffer than 1950's era metal...that's good.
I've got a custom frame from 2003 made from Columbus Zonal megatubes with a CF rear triangle and Reynolds Ouzo Pro fork. I rode it for 13 years, 40K miles, including lots of hard climbing, with no evidence of any problems.

So, I'd say don't worry about your frame materials. Pay attention to any noises or flexing, inspect carefully after any big impacts, and go ride.

I will say that if you aren't worried about the possible failure modes of the material you are riding, you shouldn't be riding high performance equipment.

There are broken CF frames all over the Internet. Most of these I wouldn't count because they are from collisions with cars and such. The the numbers of broken VERY expensive CF frames that simply failed compared to other materials is statistically relevant. Showing me a picture of a 1956 Peugeot bike with a broken seat tube made from straight gauge cheap steel does not compare since this bike today would sell in a Target for $150 and you're comparing it against a $10,000 carbon fiber bike that broke in the very first week of ownership.

https://www.forbes.com/sites/kevinmurnane/2017/01/11/new-materials-have-advantages-over-carbon-fiber-for-bike-frames/#1d0ea9e10d64