redoak

Hee, hee.............you guys are easy! I mean easy!!!!
Do you know what the word "sensationalism" means? Did you read my entire post?
No kiddin...............that's a ZIPP**********???? I thought it was a DIPP...............or maybe that was

Bob Dopolina 

First let me say that there are some very good Chinese manufacturers who deliver quality products with no surprises. But I'm not there.

By that I mean I can't jump in my car and drive to their office and look someone in the eye or drive to their factory to do QC. I have to apply for a visa and get on a plane.

That's a big difference.

Aside from my personal experiences I have friends who own their own companies in other industries who do source from the Mainland. I have heard, for years, the problems they have had. I have heard the same things from those within my industry and I have done some reading on the subject as well.

Based on those experiences, that information and the fact that I am not on the ground I have decided that the risk was too great for my company and my customers.

Nothing I have experienced or heard since I made that decision has changed my mind.

And frankly, given the 20% rise in annual labour costs and recent political developments I think the shine is off that dime and China is over. More companies are pulling out and China is about to start another long gaze inward.

There are those that do but they are not the ones selling blems on eBay. They are the ones producing branded products people on BF ride every day.

fureshi

I've been hearing this more often lately. I don't know how many here are into dragon boat racing but one of the first makers of carbon fiber oars is by a company called BurnWater, started by a college friend of mine. He originally out sourced his production to China. Originally he was drawn to China by the low production costs but due to ongoing quality issues and having to travel there continually to resolve production issues, he decided to move production back to the States. Although production costs aren't as low as from the Chinese supplier, his current supplier's quality is better and easier to manage.

Bob Dopolina 

This is exactly what I am talking about.

If you have to send someone to China 2 times a year it quickly eats away at the bottom line. At some point the advantage of being there is gone.

mpath

I've done quite a bit of business in both Taiwan and China in the past - and was a regular attendee at the Canton Fair - travelling to most of the major cities visiting various factories. I'd agree that for the most part, Taiwan production quality is still quite a bit ahead of China. That being said, however, the adage, "you get what you pay for" rings true. If North Americans still expect to pay the cheapest prices, then that's what the Chinese will deliver. But I've been to many Chinese factories that built Honda and Yamaha motorcycles for their home market and abroad, and the quality was there there.

Bob, thanks for this thread - I found it very helpful.

HokuLoa

Operative word being "cheapest" in most cases. Low price yes but often low value as well...

toshi

Check out the tire hook on these clincher rims. Completely flattens out. Taiwanese or Chinese?

spectastic

can someone ascertain the difference between chinese and taiwanese carbon clinchers? or know of a good pair of chinese wheelset right now?

What I got from this thread was how they make the rims differently. But as far as functionality goes, I'm still at a loss between the two.

Bob Dopolina 

It's hard to tell from the photo but it looks like there was a problem in the mold and they tried to repair it during putty.

Regardless of where it came from it is an utter fail.

Bob Dopolina 

A few highlights:

1. Injected foam core sucks and soaks up heat.

2. Using cheap polyester resins leads to heat failures.

3. Running molds beyond their capacity leads to rims that are not straight and will always come out of true

4. High labour turnover yields inconsistent product

5. Competing solely on price yields the cheapest product possible which ultimately results in quality fade.

There were more points but I can't be bothered to go back and look.

spectastic

not trying to undermine your statements. just trying to find the most cost effective way to get some carbon wheels. If at the end of the day, the Chinese and Taiwanese wheels both do their job, and require about the same amount of maintenance, I'll go for the cheaper one.

himespau 

I don't doubt you're right (and value your experience having bought a couple of your dashboard things from you), but I think the question was more along the lines of "how does one identify the good ones from the crap ones while avoiding dropping the extra coin on paying for the sticker of a brand name (and theoretically having the brand make sure it's one of the good ones and stand behind it)?" Though I could have misread his question.

Bob Dopolina 

You can't.

Unless you have specific information about how the products are produced and the conditions surrounding production it is a matter of blind faith.

That's why the safe route is to go with a brand or manufacturer that has a track record. There are some Chinese vendors that do have a proven track record and who produce quality carbon goods. Most of them are OE only so end users have no direct acces to their products and most likely never will.

Most of the Chinese consumer direct brands claim to be factories but really they are not. They are just trading companies who source their carbon from various factories and brand it. There's nothing wrong with doing this other than lying about the fact. To me that's the first strike in terms of trust.

The other problem is that these trading companies could change suppliers without notice to save a dime. Literally. So a product that was once stable and proven could suddenly become an unknown again (since most of these trading companies lack the resources or the desire to do any real R&D or any other kind of testing).

There are long, long threads on other forums where this has played out.

Doing some homework can help alleviate some of the worry but in the end it is a leap of faith (but then again, aren't all ecommerce purchases a bit of a leap?)

Bob Dopolina 

I don't know how to quote your quote of my post but ill stick with the points as made, in order.

1. My meaning was that rims that have the foam still inside them after production have an issue where this foam becomes a heat sink. Not what you want.

In terms of temperature during production adding more heat is not an option. The temperature of the mold during production is very precisely controlled. The factories we work with recalibrate their ovens every 4 hours or so. Things like temperature, pressure and the timing of these is very, very precise.

2. Do some research on the composition of resigns. The information is out there. Mostly it comes down to the temperature at which the resins change state. Cheaper resigns do it at a lower temp. That's why it is desirable to us high Tg resins; the transition temp is much higher yielding a rim that is far less likely to suffer heat related failures. The problem is these resins are MUCH MORE EXPENSIVE.

So it is highly improbable that cheap knock off rims use these materials as the cost makes it virtually impossible.

3. Yes, this should be something that you can research.

What I mean by this is that molds need to cool in a controlled way between each use. That means you have to wait a fixed amount of time until you can pull the rim from the mold. One mold can only produce a handful of rims a day. If you rush the process and pull rims too early in an effort to increase the output you can get rims that just aren't straight.

The problem is once they are built into wheels it is hard to tell until, over time, you realize that your wheels need to be trued far more often than seems normal. There is a cost to this for most people so the cheap wheels aren't quite so cheap over time after all if they require considerably more maintenance.

Another problem is that molds need to be cleaned after a certain number of rims have been made. If the molds are not cleaned the rims will have blemishes and extra putty will be used to correct this problem. Putty adds weight. It is also done by hand so the problem of inconsistent finish comes into play.

Molds also have a lifespan. With each cleaning the tolerances are affected. Eventually the molds will produce rims that are out of tolerance. At this point they should be retired. Often they are not or they are passed onto another factory and they are put back into production producing rims that are no longer in spec.

4. Laying up carbon requires a semi-skilled workforce. This means training. That layup and idiosyncrasies of each rim means training and time laying up THAT SPECIFIC rim. I don't want to over state this factor but it is one that relates to consistency. Inconsistent products and lax QC means more poor quality or even defective product makes it into the end users hands.

How this plays out on the mainland is directly related to the high labour turnover in China. This is low paying and dirty factory work. Many factories have an annual labour turnover of 20% or more. This means they have a labour force that constantly needs to be trained and production lines that have a constant mix of experienced and inexperienced hands at work.

This leads to inconsistent products. See above.

I have first hand experience on how this can bite you in the arse. Hard.

5. Quality fade. I love this one.

There is a running joke about manufacturing in China. When someone asks you about your experience the reply is that the samples were great...

The underlying meaning is about quality fade. This is more of an OE thing but it plays out in the consumer direct market, too.

Some factories will produce samples that are absolutely top notch and at a great price. Once the buyer is committed to the product the factory will start to slowly cut corners to make a profit. The initial samples are often produced and sold BELOW COST so the only way to make the business profitable is to reduce costs. The only way to do this is by using cheaper materials and methods.

This means that over time the quality of the products slowly decreases to the point where it is nothing like the original samples, or in the case of the aftermarket, the versions of the product that the reputation of the brand is based on, until stuff begins to fail.

Again, there are long, long threads on other forums where this has played out.

So at this point you may be asking yourself why these same problems are less likely to exist in Taiwan?

1. The business climate is very different. Taiwanese factories have been supplying overseas brands for much, much longer than their Mainland competitors. The factories that are still around have learned to think, really think, about long term business and not "money now!" This means consistent quality.

2. The labour market is far more stable. The same issues are still a factor but to a much lesser degree. Turnover is nothing like the mainland.

3. Most Taiwanese factories that have survived the flooding of the market with lower cost Chinese products have survived by not playing that game and moving upmarket and producing goods at a level not possible by most of their Chinese competitors. This means more R&D, more real testing, and utilizing their long term foreign partners in terms of design, materials and standards.

As an aside, this gap is narrowing. There are more and more good carbon factories in China but they too are losing their competitive edge as things like labour and energy costs soar.

Anyway, sorry for the long answer. I'm having trouble sleeping and thought this might help. Next time I'll leave the iPad in the living room.

spectastic

thanks for the insightful answer. I'll take your word on how the market works. I'm a chemistry guy, and I'm thinking if Tg is low on these low quality polymers, can't the manufacturer just add a crystalline additive that raises that Tg? Also, I think if an epoxy has a low Tg, then that will manifest itself through lower stiffness in the wheels. I don't know by how much, but if it's significant, I think people would notice. But if excessive heating is the only issue with low quality epoxy resins, then I'm curious if this is really a practical issue. Say the Tg is around 80C, and my brake pads never go past 50, do I really need to be worried? I see where you're coming from though, with cost cutting, and bringing those quality parameters closer and closer to the redline. I don't know, I just don't want to pay for a pair of wheels with the same amount of money I can use to visit Europe.... and I really want to visit Europe

Hiro11

It seems like a lot of people on the internet are focused on mainland resellers. I'm surprised that there are so few smaller Taiwanese brands out that make it easy to buy their wares. I'm not talking Giant or Merida, I'm talking smaller brands like Velocite, Neo, Swift, Axman and the like. You can find these brands, but it's a bit of a pain. They all make some truly cool frames in the same factories (sometimes mainland) that top end European-branded stuff is made in. I think a lot of American cyclists would be willing to pay the premium over rock-bottom Xiamen pricing to get Taiwanese quality.

Campag4life

Its much more than that. Bob stated it well. Sample integrity versus process variability over time after making a thousand wheels in a row. Control plan. Process Failure Modes and Effects Analysis. As a Chemist, you need to read a book on Statistical process control. The robustness of any product is the ability to control the process such that there is always a safety factor. This is particularly critical on a safety related item like a wheelset or a carbon fork with carbon steerer or a carbon frameset. If corners are cut, catastrophic failures can result. Big name companies become big name for a reason. Plus they are putting it all on the line with their name out there. If a company like Zipp starts having catastrophic wheel failures due to lack of process control or faulty design nominal aka Tsubg due to lack of testing, it will bankrupt the company in recalls and law suits and they know it. All large companies do what they can to protect the bottom line and they do this with due diligence. It isn't altruism either...its to protect the bottom line. If you want to go for Chinese no name wheels and go downhill on them at 45mph riding the brakes on a 90deg F day, then go for it. The engineers that design them and scrutinize their process variation may have done all that they should. I personally would prefer to ride wheels and a frame where I know they have done their due diligence. But there is more. Even with all the due diligence and exhaustive testing there is no guarantee an outliar won't get out in the field. It happens every day and has cost big companies who sweat the details to protect the customer millions.

gc3

Please don't take this the wrong way, and I'm not purporting to put words in anybody's mouth, but if you take the time to find and read everything that Bob D has previously written on this subject....whether or not you'll get a set of chinese mainland clinchers that will be defective in some manner seems to boil down to "you pays your monies and you takes your chances"....personally I got "lucky" but for all the problems reported, there is still a better than 50/50 chance of getting a completely usable product...

Bob Dopolina 

The actual chemistry is beyond my pay grade. It may be a simple as you say as long as those changes don't affect the the other properties of the resign like flow rate. For the sake of argument lets say it is as simple as you suggest.

The issue is one of cost. I do know that the high Tg resins are more expensive than polyester resigns and that is the real issue.

It's hard to make a less expensive rims using more expensive materials.

Sixty Fiver

Bob - A couple of guys in Canada are pondering the possibility of building carbon clinchers... again.

The prototypes were perfected a few decades ago and wore out the testing machines, the design is disc only so would appeal to mtb,cross, and other applications where rim brakes are not used.

My partner understands composites like few others, he has worked in this field for over 30 years.

Mark Kelly 

Tg in epoxies is basically shorthand for crosslink density. Crosslinking occurs late in curing (after chain formation and branching) so it is strongly influenced by cure cycle - the epoxy must be warm enough for the chains to be moderately mobile or they won't bang into one another often enough to crosslink to the required degree. For a given formulation, Tg tends to follow cure temperature, at a first guess you can knock 20C off the cure temp to get the Tg but this is not universal; simple amine curatives won't achieve high Tg no matter what you do but can achieve a Tg above 50C with room temperature cure.

The curing behaviour also explains why people who want to cut corners won't use these resins: besides their extra cost they also impose significantly greater processing costs because the cure cycle must be tightly controlled to get the right properties. If there's not enough chain growth before it enters the crosslink phase the chains won't be able to crosslink properly, if they are too long they will be too immobile to promote crosslinking. Some of the higher spec epoxies have much more complex behaviour - one I use cures nicely at 50 C but then requires a post cure bake at 120 to achieve full properties.

A typical high end resin will use aromatic amine curatives: the aromatic ring gets in the way, slowing the cure right down so an elevated temperature cycle must be used. As above, this will result in a higher Tg but it also gives other benefits such as improved chemical resistance. Some of the simpler aromatics will give a high Tg at the cost of increased brittleness and some of them are quite toxic / carcinogenic so more complex aromatics (including anhydrides) are usually used and inevitably these are more expensive.

BTW resin Tg mostly affects strength and toughness, stiffness is 99% determined by the fibres.

Caveat: I'm not an epoxy chemist, just an end user. I'm actually a winemaker by trade, I just happen to like chickenwire.

Bob Dopolina 

I'm all ears. I have been looking at a disc specific application myself. I wanted to find a partner before committing to the tooling and that hasn't happened yet.

Bob Dopolina 

@Mark Kelly.

Thanks for the post. That I do understand. It is interesting especially when combined with what I know about baking temps and times. Now I want to go back and review some of the work we are doing in the OE.

I have some factory visits scheduled in 5 weeks including three carbon vendors. I like to have questions ready. This will help.

spectastic

i suppose phase separation becomes an issue if you mix in additives at high temperatures, as opposed to having something more uniform. makes sense

Bob Dopolina 

@ Mark Kelly

Any thoughts on Cup Stacked Carbon nanotubes in terms of the thermal and structural benefits?