What is meant by "open mold'?
 

I keep seeing that term used relative to carbon wheels like it's old school versus a better method used today. What does it mean?

Designs for wheels that OEM manufacturers hold/build off of, and add graphics/changes to accommodate a manufacturer/distributors specifications. To be honest.. there probably isn't that big of a difference between a product sold by Reynolds, or another manufacturer who builds a similar product, except with a open mold design.
open mold: any bidder willing to sign a contract with us, we will build the wheels for you.
proprietary: legally (and I mean, "legally" we aren't supposed to make this design except for whoever gave us the specifications.)

And in some cases the buyer actually owns the mold and installs it at the molder only to be used for himself.

That's why I said, "legally" lol.

A lot of frame designs are also supposed to be proprietary (BMC, Colnago, Pinarello, Specialized, you name it) but counterfeits often appear. It's possible the counterfeiters reverse engineered an actual bike..but more likely, the molds or schematic that were supposed to be kept in-house were released, on purpose or accidentally.. and that is probably why counterfeit bike frames exist, also.. the design is often different in some details because the molds could have been altered for easier manufacturing or they were a an earlier mold/prototype.

Molds may be costly to make, but it's the lay-up that makes all the difference; which prepeg where, and how much dramatically alters the performance of the design. So while two frames may share the same look because of the mold, they can be very different bikes in terms of ride quality and durability.

not to be rude but, where did you hear this from/ is it repeated info you are repeating?

i know it sounds logical but i always wondered if it was mostly horse dookie.

i would like to hear it from someone who isn't trying to sell a bike and whom isn't just repeating what they heard.


thanks

Bdop, who has extensive industry experience has made this point in numerous threads.

I that in boat building that the material chose, how it is laid up in the mold, etc, have a huge effect on the end product. I would assume the same is true in bicycles.

Coming from a physics/engineering background I can confirm that this isn't just horse dookie.

Open mold wheel. . .
http://img.photobucket.com/albums/v8...pssy4hzm4r.jpg
of cheese!

With proprietary fungi. :D

Yes. Dimples for extra aero.

Blue cycles' new disc?...

One doesn't even need industry experience to know this; anyone who knows anything about carbon fiber knows it cannot be any other way.

I'm one of those rare specimens who has actually ridden both an $8,000 genuine article and its $800 Chinese reverse-engineered counterpart. And for me, there is NO discernible difference in the ride quality of the two!

I built up an $800 replica aero carbon frame I bought from China. It's a beaut!

A bike shop let me test ride the $8,000 genuine aero-framed road bike on which my $800 replica is modelled. That was after I'd returned - after renting it for a week - a $2,000 roubaix-specific road bike made by the same company that makes the $8,000 aero one. The rental bike was 4 levels down from the $8,000 one on that company's pecking order of bikes. I couldn't tell any difference in the ride quality between those two either.

I don't believe there is more than 2% of the entire universe of bike riders that can honestly sense the subtle nuances of difference that a few micrometers thickness (or whatever) might make in the layup of a carbon fiber bike! I like to think of myself as a pretty perceptive person. But I certainly can't perceive those subtle differences. And I'm grateful that I'm in the majority on that score.

I don't race. Never have. Never will. I may not have ridden thousands of bikes in my life. But I know when a bike's riding quality feels nice to ME and when it sucks to ME. And that's what I go by. How a bike feels TO ME! I'm not persuaded one iota by what the glossy bike porn in the magazine ads try to persuade me to believe. And the Poindexters in white coats and pocket protectors might as well be talking Latin for what all their arcane jargon means to how a bike feels to ME.

In my opinion, I suspect there are a lot of people who disparage lower-priced Chinese carbon bikes that have never themselves actually ridden an $8,000 genuine Trek in a side-by-side comparison to its lower-priced Chinese cousin - "Chrek". Instead most people take the lazy way out and unquestioningly swallow the ad men's Kool-Aid. I'd like to turn those easily suggestible people on to this fascinating episode of Nat Geo's Brain Games. Watch it if you ever get the chance. And learn!

I wouldn't rule out the possibility you're just indiscriminate, though.

In electronics you can find a lot of ebay special knockoffs from china. They look the same as what they copy, they function the same as what they copy. 99% of the time, the difference is pretty minimal.

But when you crack them open, you often find price cutting shortcuts and bad design, that can sometimes turn them into deathtraps waiting to happen. Designers don't understand, don't have the budget for, or simply don't care about safety, so it gets left out. Some are designed by people who clearly have no idea what they are doing at all.

When you buy a noname clone, that's a risk you take. Do you know what, if any, engineering went into the layup? Do you know where they cut corners? If something ever does go wrong, will you ever be able to track anyone down?

I too own a chinese frame and 2 big name frames.

the china frame is more flexy but other than that it's a great frame.

I think the flex is partly due to the frame design that it was copied from.

i won't say what frame they may have copied but it rhymes with Cervelo R5.

Yes. Reverse-engineering! Are you suggesting that laying up carbon fiber is some kind of unknowable black art that can only be learned by the uber-elite? Or are you saying that Chinese people are incapable of learning how to layup carbon fiber? On what do you base these assertions?


Yes. They've cut costs by cutting several levels of middlemen out of the distribution chain by selling direct to customers!


Yes I would. What makes you think I wouldn't?

Now that I've answered all of your questions, how about answering mine. In particular: Do you now or have you ever owned - or even ridden - either an open mold frame or a reproduction Chrek, Chiant, Chinervelo or Chinarello?

I thought not!

You can see on Busted Carbon instances of frame failures of every single name brand bike. Stuff happens! Just ask Romain Feillu (of Team Bretagne-Séché Environnement):

http://www.rtbf.be/video/detail_romain-feillu-casse-son-velo-en-deux?id=1900354 What happened there was called "The Luck of The Draw"! It had nothing to do with the country of origin of the bike. But for the record, the bike's a Swiss/Italian KEMO. That happened last week in the 2014 GP Le Samyn.

Statistically, more people are injured in their own homes than are injured on Chinese carbon bikes. You're statistically more likely to die at the hands of your wife than by the mythical exploding Chinese carbon you so fear.

@ BikeLockHolmes,

I'm glad YOU enjoy YOUR bike and I hope you continue to enjoy it for years to come.

Regarding your assertions about the differences between frames, a couple quick questions:

Have you ever done destructive testing on any carbon frames? Have you even seen how two frames from the same run can fail at drastically different points and under vastly different load or cycles? That's not usually a good sign.

Have you ever cut stuff open to see how well the lay-up was executed and what the inside of the tubes looked like? How the resin had flowed? Or if perhaps cores or bladders had shifted in the mold causing uneven areas or imbalances in the cooked carbon? Seen voids?

Have you ever been involved in manufacturing and seen how many steps are involved and how much labour is needed to produce a good? Most involve many unseen steps that deal with minor details that, collectively, affect the consistency of the final product.

Have you seen how many bakes, at what temps, for what durations carbon frames go through and wondered how consistant that was or if perhaps frames were removed from the mold a bit too early each time to increase the capcity of the mold by one more frame a day messing up the alignment?

Or wondered how well the prepreg was stored? At what temps? Or if it was cut with the correct bias or if shortcuts were taken to reduce the amount of wasted prepreg? Or wondered how closely the factory followed the expiry dates on their prepreg?

If you had done any of these it might give you pause to wonder is there is more to making a carbon frame than materials and lay up schedule.

I completely agree with you that most of these things can be leaned and copied by those Chinese factories that decide to steal intellectual property and knock off frames. The real issue is executing all of these tiny steps correctly and consistently, with an annual labour turn over pushing 20%.

I look forward to your thoughts.

Comeon, don't introduce logic into this, they look the same! Can't you see that? Seeing is believing! A sample size of 1 is good enough, as long as I get the good one!

Like I said. You might as well be speaking Latin, Bub.

Listen. I'm just a regular Schmo who builds and rides bikes for my own enjoyment. I don't ride in any pack, group, team or club. That's because riding my bikes to impress other people is not my schtick. I don't have any patents, trademarks or copyrights registered in my name. So somebody else's stolen intellectual property doesn't keep me awake at night. That's the intellectual property owner's problem. About which I honestly don't care. How to not spend thousands of dollars when I don't really need to? Now that's something I care about a lot!

But you seem like a nice old fellow who knows a thing or two about carbon fiber. So here's my answer to all of your "Have you ever...?" questions in one fell swoop: No. I have never. But I have a guy who is expert in that field that has! His name is Yong. Cycling Yong. If you're ever in Dongguan China, drop in at his factory and say hello. You will be impressed with what you find!

If you rode faster those things that you can't discern might be important.

I have been to a dozen carbon factories. It would take a lot to impress me at this point. And, quite honestly, I don't get impressed by dog and pony shows anymore.

What does impress me is product with consistent quality, within spec, delivered on time, for the price agreed upon container after container.

Let me know when your Mainland 'friends' figure out how to do that.

Translation: I have no idea what I am talking about but I am adamant in my uniformed opinion that supports my purchasing decision.

And it's Bob, thanks.