Thursday, November 10, 2011

Carbon 29"er Wheels: Black Magic Or Bad Disco?

Easton EC-90's
As carbon fiber components continue to encroach upon seemingly every part of our bicycles, particular fear and resistance has been aimed at mountain bikes frames and wheels made from the substance. Oddly enough, the arguments against carbon are contradictory with regards to frames and wheels. One says carbon frames are too fragile for mountain biking, while the other claims that, although carbon wheel strength is almost never questioned, the prices are sky high and "not worth it" compared to aluminum rimmed wheel sets.

That in itself could be its own blog post, but what I wanted to cover was that carbon fiber wheels are revolutionizing the way riders are looking at 29"ers. One only has to go back several years, (or read British mountain biking magazine articles from the present day), to remember that a common argument against 29"ers was that their wheels were to heavy and weak. Not anymore.

Take a quick gander at those Easton EC-90's there. Light? How about a real world weight, (weighed on my scale), of 1450 grams for the pair. (Easton claims just a touch lighter than this.) Okay, but how stiff are these? Let me tell you something- If these rims were aluminum, I would kill them in fairly short order. I happen to be a fairly smooth rider, and wheels last longer under me than with some folks, but if I had banged the aluminum rim like I have banged these, well......the rims would be pretty dinged up by now. 

That's the thing here though. Yeah, so what? Carbon is tough, stiff, and all that, but at what price? The price. Well.........expensive would be a nice way to put it here. $2500.00 is not cheap by any stretch, and you could probably source some hand built aluminum rimmed wheels for a quarter of that price that weighed close to these wheels.

UST rim bed = tubeless ready
Then it all comes down to longevity and performance. Hands down, the carbon wheels win. The thing is, you would have to go through four sets of high end aluminum wheels to equal the price of one set of the carbon rimmed wheels. The other thing is could you put up with slightly flexy wheels through all of that?

Finally- Do carbon rims hold up? If you buy from the leaders in the technology today, the answer is yes. They do hold up. Are there carbon rim failures? Sure there are. But you have to ask yourself: Would an aluminum rim have survived that accident/crash? Not likely. If you have a good company behind you, there are some warranty/crash replacement policies to help you out.

Those are a lot of things to answer and consider, but one thing would make all of this much clearer. That would be if the price of carbon wheel sets comes down. If the performance aspects can be kept, and the weight can be kept low, and the prices brought down to well below 2G for a wheel set, the equation gets a lot easier to balance. I suspect this will happen sometime.

Especially when you consider high end aluminum wheel sets can be as much as 1G or above, a cheaper carbon hoop set would strat to make a whole lot more sense. Time will tell..........


rideonpurpose said...

It is odd that people worry about the frames being fragile, but have faith in the wheels.

I wonder if this is due to a couple of large manufacturers recently trying to go too light with some high profile frames? I know we've seen a ton of broken bikes here in town from one particular manufacturer.

It would be sad if their mistakes hamper adoption of new technology.

Guitar Ted said...

@rideonpurpose: I agree. carbon has been proven to withstand quite a bit of abuse when designed right for the task. However; a fear of anything carbon, and especially frames and seat posts, seems to be prevalent in mountain biking.

Handle bars and wheels made out of carbon seem to get a free pass though. It is a strange thing to observe.

Jim said...

Aluminum rims might fail, but when they do your wheel will taco at worst. When impacted the right way carbon is guaranteed to fail catastrophically, that means "in several pieces, and right now". And the rider will be on the floor. Carbon stems and handlebars and seatposts are usually heavier than aluminum because of the additional material thicknesses required to make them safe. I don't see the point but that's marketing at it's very best.

Guitar Ted said...

@Jim: It is dangerous to make generalizations on materials and how they may, or may not, fail. We have several examples of carbon frames here at the shop where I work that have been damaged, but didn't come apart in shards or separate, and I have an aluminum wheel in front of me as I type this at the shop that split completely in half due to a poor design.

So, when speaking of companies with reputations and lots of money and livelihoods on the line, I think it is safe to say they have done some "homework". Some others, maybe not so much, and outsourced products have another layer of uncertainty.

To make a blanket statement on how materials may fail and on weights of products, and to blame this on "marketing" seems a dubious thing, at least to my mind.

rideonpurpose said...

I've never seen a carbon wheel break while riding in a manner which lead to a fall... maybe those old spynergy wheels?

Aluminum as a material is more prone to complete failure certainly.

show me some full carbon bars or posts heavier than al? regardless the point is ride quality.

Jim said...

Well, my comments weren't about frames. Even so, your "damaged" carbon frames need to be thrown out right? Part of the "homework" these companies have done requires that they provide disclaimers that recommend retiring carbon parts that are so much as suspected of being damaged. I have only ever seen one aluminum rim fail and that was because it had been ridden for so long that the sidewalls were worn so thin that the tire exploded the rim apart. I have seen more than one carbon rim explode in pieces resulting in serious injury.
As for stem weights, let's see:
Ritchey WCS 4-Axis= 125 grams
Ritchey WCS 4-Axis 44 carbon= 124 grams.
OK carbon is lighter by one gram, but also double in price.
Deda Elementi ZeroNero carbon= 150 grams
Deda Elementi Zero 100 Servizio Corse alloy= 140 grams
Deda Elementi Newton 31 alloy= 125 grams
Deda Elementi ZeroUno alloy= 140 grams.
3T Arx Ltd. carbon= 120 grams
3T Arx Team alloy= 120 grams at 1/4 the cost of the carbon.
generalization? blanket statement?

Guitar Ted said...

@Jim: Fine. I am not here to argue the point, but your first comment left me a bit unconvinced, and your second one shows me a few examples, which I would grant you specifically on weight, but the opposite examples can easily be found as well. This only proves that design and engineering can use any material well, or not. It doesn't say one is worse than the other, which is what your original comments implied. Make sense?

Jim said...

rideonpurpose, you say "Aluminum as a material is more prone to complete failure certainly." Really? Carbon fiber bike bits are made of layers of material held together with glue. If any of those bonds or laminations is compromised, by, for example, a fall on a mountain bike where the rim is impacted on a rock, or a rock dinging a carbon mountain bike rim while j.r.a. , the part is prone to failure. Look at the disclaimers provided by ANY carbon fiber part supplier.
You also say "show me some full carbon bars or posts heavier than al? regardless the point is ride quality." OK, I redact the statement about bar and post weights. But, how does a carbon post or handlebar or wheel improve ride quality?

Guitar Ted said...

@Jim: Carbon does stiffen up structures beyond what seems to be capable of for aluminum, steel, or titanium for a same weight-to-same weight comparison.

So, in terms of wheels, (that I have personally ridden), and structures like frames, carbon makes the ride better by eliminating unwanted flex at an attractive weight.

The intangible of ride quality is a very subjective thing, but I do think there is something to it.

Structural stiffness is definitely the biggest advantage I see, however. My Edge carbon rims are simply amazing in this regard.

rideonpurpose said...

I race and ride repaired carbon frames and wheels. They do not need to be thrown away- mail them to me if you distrust them.

Carbon can be made very stiff- it also has a much longer fatigue life than aluminum. It can be made so that it flexes without wearing out prematurely. It also has a deadening effect on vibration. Obviously, people who just spent way too much money on bars, stem or seatpost are likely to have a placebo effect and think it vastly improved their ride quality... but it's inarguably real with the good stuff. It would take a lot of cynicism to think the manufacturers have gone this way because it doesn't work.

Ever see the way aluminum things break?

Don't get me wrong- I trust my aluminum parts too...

Carbon isn't exactly layers glued together either- but those layers and strands are actually what does make it fail in a more controlled manner than most metals.