kbarch

That's not what I was saying at all.

If all a product offers is crap, even if it's 100% crap 100% of the time, it's still crap. If you think 100% crap is higher quality than a flawed masterpiece, you should be interested in a deed for the Brooklyn Bridge I have to sell you; it's perfectly valid, and you'd have to say it's quality is impeccable. I, however, would not say it's quality was very high.

If something meets a spec, it's not high quality, it simply has that quality. In the sense of an attribute, the notion of a quality exists independently of standards, but yes, the establishment of a standard is what determines the extent to which something has it or not, and standards are either dependent on context or essentially arbitrary.

What you describe as "the way quality works" pertains when one is comparing things that are supposed to be similar. For instance, "tall" is a quality in the sense of being an attribute, for which standards are typically contextual, e.g., a hill is not tall if it only measures nine feet, but if a man measures only eight feet, he is VERY tall. The same holds true for things that are somewhat, but not entirely similar, and standards are arbitrary. For example, if all Huffy bikes met their spec all the time and all Argonaut bikes met their spec all the time, it would be unreasonable to say they were therefore of equally high quality, simply because there is the notion of an ideal bike, a sort of over-standard beyond the arbitrary specifications that the manufacturers set for themselves. Both makers set standards above garbage, and both set attainable standards, but they didn't set them at the same point, and it is the point at which they set their standards that determines whether one is higher quality than the other when they both meet their own specs as you describe.

joesch

+1 my thoughts exactly. I only have 1 CF bike and hope Cervelo has better fabrication. I was also considering a BMC and was told they do not warranty the frames which is why my LBS stopped selling them.

RPK79

If anyone in this thread is looking to unload their BMC frame for cheap let me know.

pvillemasher

That MTBer probably crashed off a cliff, landed on the pedal, and it broke.
So probably not Shimano going too thin, and probably not a manufacturer defect at all.

But it sure is fun to speculate...

MidTNBrad

I'm in the exact same boat. I was looking at a BMC a couple of years ago and the LBS told me they only warrant their frames for 5 years. Cerverlo warrants theirs for the lifetime of the original owner. That was one of the reasons I got an R3.

Edit: I would speculate that if someone cut open an R3 it would look pretty similar to the BMC.

woodcraft

I thought, watching the video,

that there is no functional benefit to the fancy tube shapes.

Slick Madone

Was this frame ever verified to be a factory original frame or a copy?

rpenmanparker 

You must have had different quality training than I did.

kbarch

Excellent insight. It reminded me of motorcycles, and how high-performance bikes cost an arm and a leg to maintain. The fact the out the door cost didn't seem much higher made them seem attractive at first to a lot of folks, but once they realized how often they'd be bringing them back in for valve adjustments and such, and how much all THAT would cost, they thought again.

It's all about priorities.

Bob Ross

When I bought my first carbon frame in 2006 I chose a Cannondale over a Bianchi for that same reason: Cannondale offered a lifetime warranty, whereas Bianchi only offered a 5 year warranty.

But I later found out that this discrepancy had more to do with European liability laws than the manufacturer's confidence in their product. At that time (and perhaps still?) no European frame manufacturer offered a >5 year warranty.

Kontact 

A better question is whether the manufacturer has any idea whether that great a departure from the design is safe or not. They likely have no method for modeling that kind 3D variance with any accuracy, so the whole frame becomes a big roll of the dice.

The statistics of failure rates are pretty immaterial if you are in the hospital after your seat sheared on hard bump. Quality control is not an engineering variable that can be controlled for other than by paying insurance premiums.

memebag

Say what? Quality control is a tangible process. You can buy as much or as little as you want.

pvillemasher

Is what was shown in the video a departure from the design?
What if you cut up another of the same frame, would it look different?

mstateglfr 

A few comments, even though this is deep into the thread.

- The BMC frame looks significantly worse inside than a Cannondale frame and a Giant Defy I saw in person. The section where the top tube and head tube join looks like my 1st grader built it.

- I have 0 idea if the inside at all affects performance or reliability. If it doesnt, then it just isnt important.

- The fact that other frames are able to be much cleaner inside shows its possible and if the bikes cost comparable amounts, then comparable quality is expected.

- I find it deliciously ironic that the OP has made unsubstantiated claims about quality and declared unknowns to be known at various points in the thread, all while hedging that he hasnt.



Carry on with the Engineering speak.

Kontact 

Sure, but when you 'buy' lower QC you are choosing less control. Less control is essentially random results.

I don't see how you could produce those kinds of internal voids consistently. Can you? That one area looks like a sectioned snail shell.

chaadster

The guy in the video has probably a dozen frame cut-up videos. Go watch 'em. You can clearly the see the differences in production quality...well, some of you won't know you're seeing differences in production quality (some of you have no idea what quality even is), but that's what it looks like.

If a carbon fiber expert cutting up a variety of frames in the same way from different manufacturers and explaining to you what you're seeing doesn't substantiate the notion of production quality differences, then you really have a problem with understanding. If your only critique of his process and findings is that you've never heard of the guy, that really says more about your shortcomings than his.

As a favor to everyone in this thread, I'm offering custom bike paint jobs at a real great price. Just send me your bare frame and I'll paint it for $100. Any Krylon color you want! It's gonna look like crap, but it'll be to spec, i.e. covered in paint, so real high quality. I probably won't miss a spot, I promise!

memebag

Alternatively, we just don't believe everything we see on the internet.

I'm willing to learn. I don't know how many miles that bike has on it. I don't know if it's been in a crash. I don't know if the void was there when it came from the factory or developed later. I don't know if the wrinkles matter. I don't know if the inconsistent wall thicknesses are by design, or if they matter.

If someone can answer those questions then I will know if this video means anything. Until then I remain skeptical.

memebag

Right. But that isn't what you said. You said quality control couldn't be controlled, and all a manufacturer can do is buy insurance.

Kontact 

And you're not understanding what I mean:

Lowering QC is not like increasing a tolerance - you aren't settling on a known decrease in layup compression, for instance. You are settling for an increase in random flaws of unknown impact.

So you can control your level of QC in terms of increasing it, but you can't control how lower quality manifests in the product.

Another way of looking at this: If you can't control every process, you can't have expectations of quality for those uncontrolled processes. Not having any expectations, you can just buy insurance and hope the number of failures is low enough to not affect your bottom line.

To my eyes, the seat cluster looks like the tooling design does not effectively match the frame design, and the layup ends up a random mess of unconnected layers.

02Giant 

From the video, I can see why they don't.

95RPM

What kind of forks do you use? What do you trust? It is hard to find a good metal fork, and carbon forks have that same trust issue as the frame.

chaadster

I do hope you're getting through to someone! I honestly cannot believe this understanding is over people's heads...

Seattle Forrest

You could cut the Cervelo open and find out. How's it ride?

79pmooney

[QUOTE=95RPM;20051467]What kind of forks do you use? What do you trust? It is hard to find a good metal fork, and carbon forks have that same trust issue as the frame.[/QUOTE

Steel. Two 531, two unknown (but probably 531) and a mid-range ~'83 Trek. Trek has a good record with steel forks, three of my 531 or maybe are custom and the last is a 531 Raleigh. I did not trust the workmanship on the Raleigh so I had the paint stripped and inspected carefully by a good frame builder.

Steel forks may not be sitting in every shop but in the US there must be several hundred framebuilders who can crank out exactly what you want for not much more than a high end carbon fork. (And you get to choose the type, crown, geometry, braze-ons and paint or chrome. And it will be compatible with your favorite headset. Threadless or quill. Any carbon forks offer so many choices?

I will never own a carbon fork. I've had a non-steel fork do the sudden/no warning fail and it cost me a lot. Knowingly chancing that again when I have a choice? Nah. (And carbon steerers? Wrong material for the job. Yes it is strong enough in ideal conditions and much lighter. But in the real world, stuff happens. Makes no sense to me to not use a material as perfect and idiot proof reliable as steel. (Though I would consider titanium as part of a well made and engineered titanium fork. I loved the ride and feel of the aluminum fork that cost me so much. I think the right titanium fork could get close to that feel and keep the reliability of steel.

Ben

joesch

It rides great. Im pretty sure it will not last longer then my columbus frames from the 80s but its the best short term for riding fast. I will be sad when it cracks from an accident that would only scratch paint on a metal frame.