Biercycle

A little context: I am 6'5 and around 215 lbs, give or take a few depending on the time of year, and just this past week had the frame of my main bicycle fail. It is an aluminum frame endurance bike from a name brand and developed a crack in the seat tube a few millimeters above the top tube weld (between the seat post clamp and the top tube weld). I have taken it to my LBS where I purchased the bike a little over a year ago and warranty procedures are under way.

This is the second bicycle frame I have had fail. Previously I had the seat tube on my old hybrid shear a few centimeters up from the bottom bracket. I was around 250 lbs when I purchased that bike and started riding. I put a good 5 or 6 years on it doing city commuting and weekend rides. I was a little surprised it broke the way that it did, but I put a lot of wear on it. Not so much with my newer road bike that just broke this past week. Summary over.

The guys at my LBS have been extremely helpful (even since before I purchased this bike from them) and I dont think they were giving me a line of marketing BS (they were not trying to sell me anything), but I wanted to get a second opinion from the community. I asked them what I could do to prevent these types of things in the future. I know I am a big guy, but I'm not huge. This failure rate seems a little too frequent (in my relatively uninformed opinion). They said there wasnt really an answer and that frames fail. They did suggest that the allowed flex in carbon fiber frames will cut down on stress fractures like what just happened to my road bike. They were also saying that CF bikes can be built more to purpose and adjusted based on the size of the bike and rider so that stressed areas get built up more.

Im just not sure what the answer is to reduce frame failure rates. Steel? Titanium? Custom built so that I actually get a properly sized bike for me?

Im curious if other people experienced in the industry have any thoughts on failure rates, merits of frame material X versus Y, or general advice for frame styles/types for those of us who barely fit 61cm mass produced bikes?

Thanks!

squirtdad

If you look at recalls it seems like certain designs/bike models have more problems than others.

My theory is that one contributing item is that there are fewer frame sizes and with the sloping top tube there is a lot more leverage/stress on the seat tube from the seat post.

My preference is steel. It is well proven, has slow faiilure mode. Steel also has a proven longevity, given minimal care

What is your budget for a bike? there are steel options out there and of course there is custom

Aluminum and Carbon are not bad materials, but both have sudden failure modes.

Carbon, especially in lighter builds, needs to have more care taken with it to avoide deep scratches, dents, over tightening of parts, all of which can reduce the integrity of the carbon/resin composite


Anectdotally, My wifes bike, aluminum frame had a headset crack. it was an electra cruiser and not ridden hard or abused. Manufacturing defect or design? A coworker (cat 1 racer) went through 3 carbon frames from either Trek or specialized (on warranty) due to cracks before he got tired and switched to Leopoard bikes.

as an extreme example, I have a torpado that sat outside in all weather for 2-3 years before I got it. A bit of clean up and big fight to get the seatpost out and I ride it almost daily. I don't think I would be comfortable riding a carbon bike that got the same treatment, especially UV exposure.

ymmv

10 Wheels

I had two Felts crack.

Stadjer

Steel frames usually need decades of unattended rust before there's a chance of breaking. I'm not into endurance biking and have no idea about those frame sizes, but I don't believe that frames for people of your height aren't mass produced anywhere. Where I live you're just 1 inch above the average size of an 18-year old male, that's the region, not the whole country, but there certainly is a demand for taller bikes. Normal commuter bikes here go up to 65 cm for the standard male bikes. So maybe it's cheaper to import one from Europe than to have it custom made.

jsigone

that area of cracking likely due to over clamping or the tube shape is slighly out of shape.

I wouldn't worry too much of it if they replace the frame. Use a TQ wrench on seat post clamps, stems, handlebars.

Biercycle

Thanks for the input folks.

First off, I do have a torque wrench and make sure that the bolts are tightened to the appropriate setting.

The more worldy and experienced I get, the more I am inclined to go with custom everything. The world is not built with people my size in mind and nothing out of the box works very well for me. Unfortunately, I am not in a place to go the custom route with a bicycle just yet. I will have to make due with whatever solution the warranty provides and keep an eye towards custom for the future.

I may be making a big deal out of nothing. I just tend to be overly cautious given my size, the wear that causes on bikes, and how much I have dealt with breaking things on bikes in what I dont consider to be a particularly large amount of time (many spokes, a seat post, some freewheel issues, and now two frames).

TrojanHorse

Well, you're definitely not too big for the bike, so put your mind at ease. I think you just got unlucky.

As for frame material, frames break and it doesn't matter what they're made of. Just get the warranty replacement and keep on keeping on.

pdlamb

If you're worried about light bikes under someone your (not all that heavy!) weight, have you considered getting a touring or 'cross frame and moving components over? Keep the light wheels, etc., and put an extra half pound to a pound of metal underneath you on the frame.

indyfabz

When you are in that place, go see Drew at Wissahickon on Germantown Ave. in Chestnut Hill. He will build you something like this that will fit you like a glove (I am 6'2" and was about 215 lbs. when I picked this up a year ago last May):

adrien

I'm 6'3, stable at about 212. Started a decade ago at 260 or so. i am now strong, BB, pace line rider.

It's the frame, not the material. I disagree on the odds of it being a clamping issue. It's a fatigue crack in a very high-stress area, based on a slightly under built frame (built that way to flex more and be comfortable, probably) and the result being it moved repeatedly outside of tolerance. If you tell us what it is, I can be smarter, but I respect your desire t not badmouth a manufacturer who is trying to do right by you. I did exactly the same thing to a cross bike that was not designed for me to be hammering on it for thousands of miles. It was replaced under warranty, and I promptly sold it. Once something has failed on me once, it's hard to enjoy the same thing without worrying about ever bump.

In terms of materials, any will work. Aluminum may be the worst choice, though the next one could be fine. Its issue is it can be relatively brittle with repeated stress forces applied, and it tends to be very stiff. So if it is built up enough to not flex and not crack under you, then it doesn't flex so it can be very rigid in how it rides.

BUT, and this is the big BUT...the vast majority of bikes are build for a 150-180 pound rider, and for that rider to do maybe a few hundred miles a year. Very different from a 215 pound rider putting on (in my case) 4-5,000 miles a year.

Steel is very nice, flexes a bit more and is less prone to stress fractures. It's also easy to manufacture for frame builders, and any number of great steel custom bikes can be had for not much more than production bikes. Yes, that would be a great choice.

Carbon is highly variable, and some people love them. I do not -- I've ridden dozens, and most (not all) feel relatively soulless to me. Very efficient and often very engineered, but it seems like they are trying to adapt a material to feel like another. Like the Roubaix, which is a great carbon bike engineered to feel like a classic steel bike. In terms of durability -- well, if you can be careless with things like the bike falling over or bumping into things, carbon can be a bit of a pain. But as long as you're not trying to get the lightest out there, it'll be fine.

Ti is lovely, but it's expensive and can be very hard to work on, so its builders tend to earn a premium. Top-end custom ti can get expensive, though still less than top-end carbon production bikes.

If the sport is one where you spend a lot of time, yes, custom may be in order. Not only can the tubing be specified for you, but you will also get a ride that is unique, so the new-model-year obsession won't hit. I got a second custom bike last summer, and it's still the best bike I've ever had, and I have no pangs to get the new model. That Engin is pretty, though I prefer Ti unpainted, I can certainly appreciate it. And you could choose whatever you want.

indyfabz

Thanks. Personally, I don't like bare ti, although I have seen some Engins with etched tubes that are sweet. BTW...That's not paint. It's Cerakote, which is a ceramic coating. Custom blend of Zombie Green and Glossy White. (The colors are matte, but if you mix them with gloss white you get a pearl finish.) Its main commercial application is coloring firearms. You spray it on and bake it in an oven. Enve even approves of its use on their forks. No priming and no multiple coats. As a result, it's cheaper (less labor) and lighter than paint. It's also as least as durable as paint. IIRC, the coating job cost me $300. It was done by Paint By Todd. The guy does great work on bikes and other vehicles.

PatrickR400

Just out of curiosity, was the seat post inserted below its maximum extension? I wonder why a crack would develop in this particular location without repeated flex, and how flex would be allowed if the seat post was sufficiently inserted.

jesspal

thats what i was thinking as well

Wilfred Laurier

I, too, was also thinking that as well.

I had a frame break (steel) at the same spot years ago. The frame in question had a fairly long (like 50 mm) seat tube extension above the top tube junction, so even with the seatpost's minimum insertion line completely inside the frame, almost all my weight was supported by the cantilevered extension above the top tube. The correct solution was to get a longer seatpost than the stock (and standard) 350mm one.

This also brings to mind another concern - at your height (same as mine) you are likely just on the edge of fitting correctly on the largest sizes most manufacturers offer. A bike shop might take out the largest bike they have and say 'good enough' because they don't have a better solution, but just because there is an 'XL' sticker on the bike doesn't mean it will fit you. Different manufacturers build different fitting bikes, so while an XL or 23" or 64cm from brand X might fit fine, an XL or 23" or 64 cm from brand A may not.

Out of curiosity, what brand of bike just failed on you? You can PM if you don't want to publicize it - all manufacturers have failures and a report of a single broken frame, if the warranty is handled correctly if applicable, is not an indication of a bad company or bad bikes.

Edit:
I did some super high-end online detective work (read the list of bikes under your avatar) and figured out what bike you are probably talking about.
Does this look familiar:

Because the unsupported rear of the tube is exactly the arrangement that I believe makes your type of failure more likely. You need to make sure your seatpost goes all the way down past the seatstay junction at least. I have been lusting over the carbon frames Jamis Renegade, but the arrangement of its seat tube cluster

gives me the heebiejeebies, even if they spent a million dollars on engineering and there have been zero failures.

sstorkel

Bull****.

ChuckD6421 

Well I'll pile on and say I thought the same thing. Fwiw I have a few years as a wrench in my past. I'm thinking at your height you're pushing the limits of the frame size, but more importantly I'm guessing you have your seat raised to about the limit (or past). You're not too tall for a stock bike, but if you want to pursue a custom job you should also know about Lennard Zinn. 6'6" and used to race Cat. 1.

dr_lha

Metal fatigue is the major downside of aluminum, so it's not really true to say it's "not the material". Steel and Carbon frames don't have that issue (carbon tends to just get more bendy as it gets fatigued, for example).

However that said, the frame designer should know how to design aluminum frames so that they are tough against metal fatigue, usually ensuring that the frame is super stiff so it can't bend in the places where it wants to, thus avoiding the metal fatigue issue.

To the OP: care to name and shame the brand?

Biercycle

I had about 2cm to the minimum insertion line. The seatpost was inserted well within the limits of proper use.

It is pretty clear to me that it was still the force put on the seat tube by the seatpost that caused the crack in the frame. But everything was within the limits as specified by the manufacturer of the bicycle.

Maybe it was just a lemon of a frame...

Biercycle

You are right on. That picture is exactly correct and a longer seat post is the correct solution. That doesn't change the fact that the frame should be warrantied as the failure was through no fault of my own.

I am right on the edge for the right size of the bike, which is a 61cm frame. I tried a few others in that size from other brands and it is a lot like buying a pair of shoes: just because they have the same number on the decal doesn't mean they are the same size. In my area, there was only one 64cm bike that had the groupo I wanted and it was at least twice as much as the bike I ended up with and thus out of my price range.

As an aside, I love the bike despite the failure, it fits me well, and I would recommend the brand to anyone.

dr_lha

OK forget it, it's Felt. Apparently I'm too stupid to read your bike list.

PatrickR400

Well, it sure looks like a bad design. If the length of seat post that extends above the top tube is greater than the length of seat post that is in the seat tube, you will get a bending moment, which overtime will fatigue the metal.

The type of metal influences the time it'll take to fatigue the metal, but it is a question of time. Of course you could use metal that is "soft" but then it'll bend before it breaks. Still no good.

Why not carbon fiber? I have a carbon fiber bike and I love it.

Jarrett2

If you like orange, Black Mountain Cycles offers a fairly light steel frame in size 60 & 62 for a reasonable price:

Black Mountain Cycles: Black Mountain Cycles Frames

I'm 6'1" and prefer a slightly smaller road bike. I built up a 56 and really like it.

Check out the "Road New" geometry at the bottom:

cyccommute 

Perhaps but I'd expect to see far more reports of broken seat tubes than I've seen. Sloping top tubes have been around for a very long time and mountain bikes have had used extraordinarily long seat posts for a couple of decades now and it's just not a problem that gets reported a lot here on the BikeForums.

It's fine if that's your preference but don't be under the mistaken impression that steel undergoes a slow failure mode. Have you broken a steel frame or steel parts? I have. The two frames I broke were both fine until they went "PING" and were broken. Spokes do the same. I've broken pedal spindles and axles as well. All of them steel and all of them failed suddenly without warning nor bending.

Steel is a ductile material and can bend but it is also brittle and will often just shear at a weak point. Look at the I-35 bridge collapse in Minneapolis. No warning.

No, they don't have "sudden failure modes". Welds and joint can fail suddenly but so can steel. A crack in an aluminum frame propagates slowly and the metal tends to tear rather than shear. I've also broken two aluminum frames and many aluminum parts. The aluminum cracked and creaked for a very long time before I noticed what was going on. In both cases, the aluminum never cracked all the way through. I've had a steer tube break on a fork recently and it was the same kind of failure mode. It was acting "funny" for a long time before I realized that it had cracked. I've had rims crack and fail but, again, there were warning signs and they never failed "suddenly".

I haven't broken bicycle parts made of carbon...yet...but I expect the failure mode to be more like that of aluminum than the sudden failure of steel. Carbon usually laid down as a fabric with the bias of the fabric running in different directions. A failure midtube is going to have to break across several fibers that are running in different directions. This isn't conducive to a sudden shearing failure.

I have broken a flyrod when I hit the rod with a beaded nymph. That break was like a tree branch break. It didn't shear off but cracked and tore. I've seen some carbon frame and fork failures at my local co-op as well. All of the ones I've seen are, again, more like a tree branch break. Even the bikes that have hit garages look more like broken sticks than like sheared off tubes.


Sometimes stuff just happens. That's why there are frame warranties.

You are, however, larger than most people so you put more stress on the bike. You say that you barely fit on the 61cm which has me asking if you had the saddle pushed back as far as it would go on a long set back seatpost? This puts a lot of leverage on the seatpost mast and can lead to breakage. I know because that's how I broke one of my aluminum frames.

I would suggest that you look to a beefier frame design and construction. I'm not suggesting that you have to do steel, just that you need to look at the construction a bit more. You want to look at the bike to make sure that it doesn't have a long seatmast sticking up above the top tube. You should also look at the seat tube and see if it flares out to a larger diameter to buttress the bottom bracket. Take a look at these bikes




to see how the seat tube flares out to support the bottom bracket. The first bike is a Cannodale Synapse and the second one is a Salsa Las Cruces. The Synapse is an excellent bike that surprised me with how good the ride was.

Here's another bike, a Cannondale touring, that approaches the problem is a different way



The downtube is much wider at the bottom bracket than at the headtube. This bike is a touring bike that is built for carrying heavy loads. It may not be quite as sporty as the Synapse but it's not as truck like as some touring bikes.

You might also want to consider something a cyclocross bike which are built a bit beefier than a "normal" road bike.

You should probably take the replacement bike, however and see what if you have problems with it again. It may have just been a fluke.

rekmeyata

Stress fractures will occur with CF frames if you buy a uber light frame, a good strong heavier cross bike should hold up fine, but steel or titanium is better on the long haul. The reason your LBS is saying that about the CF is because that's all they sell these days besides aluminum, and they want your business and they know you're frowning on aluminum.

Even most CF forks are only rated for 220 pounds, are you willing to push a CF fork's limits? I know that the Enve 2.0 fork is rated for 350 pounds which will be more than just marginally ok for you. I'm sure there's got to be other forks out there that are also rated for 350 pound range, you would have to research it.

Not sure why you keep breaking frames because at 215 pounds that shouldn't be an issue, however since it is I would consider looking into a cross bike instead, those bikes are built more sturdier than a road bike.

If you go with titanium by chance you don't need to get a real expensive one unless you have the cash and just one. Bikes Direct sells a really nice titanium cross bike that has gotten rave reviews by professional rags for not a whole lot of money, they 4 models starting at $1400 and go to $2,000; see: Save Up To 60% Off Titanium Cyclocross Bicycles | Road Bikes - Motobecane Fantom Cross Team Titanium | Cross Bikes (these are made by ORA of Taiwan not in China). Bikes Direct customer service is not all that great but they will take care of warranty issues, but for the price you can't beat the bikes. Of if you want an American made TI bike Lynskey has one on sale for $2,000 with 105 components called the R150 which is similar to my Lynskey Peloton, but if you get this bike you can upgrade by doing swaps BEFORE you take delivery if you get it through Adrenalin bikes; I was able to swap the stock fork for a Enve 2.0, the headset for a Cane Creek 110, and the rear derailleur for a Ultegra for a total of just $225 or so difference; Matt at Adrenalin Bikes is extremely helpful.

adrien

A good friend has a BMC. Lovely thing. Leaned it against a bike stand in a park. Wind blew it over, cracked the top tube. Had to ship it to Calfee.

Nice reference to livestock, btw.