Schwinnrider

The recent thread about commuting on carbon has me thinking. I've always had a Jones for a carbon bike but they've always been too expensive. Prices are coming way down and carbon is a possiblity, either new or used.

Ideally, I'd find a carbon bike that could be used as a commuter. Rack mounts, fender eyelets, etc.

But I'm concerned about carbon's longevity. I've seen Spinergy wheels which have self-destructed. When carbon fails, it fails catastrophically, right?

Is there any truth to the rumor that carbon fiber degrades with UV exposure? I live in Florida, and UV is a year round concern?

AEO

that's what the paint/clearcoat is for.

but is there a carbon frame that accepts rack mounts?

Mooo

Yes, UV is something to be aware of year round.

My understanding is that it's the epoxy that tends to degrade in UV. However, the resin also (according to WEST epoxies) has some issues with heat. In one of their manuals, there is a discussion on the relationship between colors & temperatures (and thus strength).

The boating industry deals with this by generally overbuilding, and/or using generous amounts of gelcoat.
In the sailplane subset of the aircraft industry, there is again a reliance on gelcoat. Since the overbuilding is minimal for sailplanes, you'll almost never see a composite glider any color other than white. I've known guys to be paranoid about even blue wingtips.

Finally, read the disclaimers and warning labels provided by Trek & others. They typically have a comment to the effect of "since damage may not be visible, if you suspect the frame has been hit or involved in rough use, return it to the dealer for inspection and/or replacement." I cannot guarantee that my bike doesn't get knocked over when I'm not watching, so I'm not interested.
Someday, someone will develop a molded commuting frame with extra layers and a white UV/IR barrier. That might be worth looking at (IMO) if the price is low enough.

BCRider

If the frame is painted with a lighter color paint rather than exposing the carbon weave then it should be fine.

However I think you have a right to worry if the carbon is open to the sun. One of my other sports is windsurfing and I've got carbon masts that are just finished in clear resin just like some bike frames. When left in the sun they get STINKING HOT in a very short time. It's like the sun goes through the resin and hits the carbon underneath and heats the darn thing from the inside. It's worse than the buildup of heat you get with something that is painted black.

I don't think you need to worry about the actual carbon but there's no doubt that the epoxy used in the layup is sensitive to heat and will age faster if it has to go through a lot of cycles. But if the frame is painted then that'll reflect it away and there's no harm done. Or at least it'll take a lot longer before it's an issue if ever.

One thing though. Carbon lives or dies on the "community" of fibers. Nicks and dings to the frame that would chip paint on a regular frame may cut deep enough to cut some of the fibers. Or a local ding may flex the frame locally to the point where some fibers snap. So a carbon frame would require more care in handling than a metal one. But if you can pretty well ensure that you won't be tossing it around like some messanger rider's I've seen or a kid with his BMX that mom bought him then again there's nothing to worry about.

thirdin77

Why do you want a carbon bike as a commuter? I have a Cannondale Synapse carbon and I don't like it so much for commuting because commuting to me means: often carrying lights, often carrying clothes work clothes and dealing with differing temps at day & night which means bringing cooler weather accessories for my night ride home.

My bike has no rack or fender fittings and given how carbon has so little tolerance for concentrations of pressure, I won't take the risk of zip-tying a rack to it.

If I were you and I wanted a lightweight road bike for commuting, I'd find a rack & fender mount-compatible sport road bike or cyclocross bike. Get one that either comes with lightweight wheels & components or install them on the bike once you get it.

It seems to me that carbon road bikes are still being made only for recreational riding & racing and at least for now, there won't be any that come with rack & fender mounts.

Schwinnrider

Actually, I think the Trek Pilot has rack and fender eyelets. It's the only one, as far as I know.

Brian Ratliff

Yea... I wouldn't get a carbon bike for commuting. It'll survive the riding loads just fine. But I'd be worried about the non-riding dings and scrapes more. Keep your current commuting bike and if you want carbon, ride it for racing/training. You'll appreciate having more than one bike. You always have wheels, and it spreads the wear and tear amongst multiple bikes.

Don't worry about UV. That clear coat on top of the carbon, or the paint job on the bike, will protect against the UV rays hitting the epoxy and degrading it. Don't worry about heat either. If you can still touch the frame of the bike, the epoxy plastic holding the carbon fibers together are perfectly fine. Epoxies are all good to withstand temperatures greater than 100C. Unless you throw it into the fire, the hottest it'll get is 40 or 50C: well under the maximum use temperature of the temperature.

nasiralpharia

I have a specialized Tricross sport and it has a carbon fork, and the fork has mounts for a low-rider rack. Right now I only have a rear rack installed. I figure though that if it can handle the rigors of a cyclocross race, then my commute should be a breeze.

The rest of the frame is aluminum. I've had steel bikes in the past, but now I have 3 aluminum, and i like the ride quality of them all. Carbon is used in Aircraft and cars more and more, and I don't see failures everyday.

crhilton

I dunno. I have nothing against carbon I'm just not a fan of bikes that cost over $2k. And many of the carbon bikes under that price range I wouldn't touch with a ten foot pole due to quality issues. I won't mention what particular company makes them.

What's so wrong with steel and aluminum anyway? Or if you must spend oodles of money, how about ti?

tjspiel

The Boeing 787 "Dreamliner" that's going to be flying soon will be made largely of carbon fiber. Some of the same concerns that have been raised in this thread have been raised about that plane. Boeing of course claims that a crash in a CF plane will be just as survivable as in an aluminum one. Time will tell. I believe it's the first airliner to made of CF but there are smaller planes (personal jets and such) that use it extensively.

Not all CF is the same from what I understand so the durability of CF may be hard to categorize universally.

I wouldn't spend a lot of money on a CF bike just to commute on and I usually get used bikes anyway. There was a used one that popped up on CL last fall located in a small market a few hours away from me. It was under $500 but I didn't like the components. I'd have bought it for my triathlons, but I would have used it for commuting as well.

I have a CF mast for my sailboard and you have to take some precautions clamping a boom on it, but overall it's pretty durable. I don't baby it and I've had it for years.

InTheRain

Yep, the specialized tri-cross. You can get the S-works for about $5500 and it's a full carbon frame that will take racks on the back and front. Seems a little pricey for a commuter, but hey, I'm sure it would be one nice ride. I actually looked at the tri-cross (aluminum with carbon forks) and considered it for a commuter. I eventually went with a touring bike but for the type of riding that I like to do, the tricross would have met all my expectations.

Mr. Underbridge

Very true. If there is a theme to CF though, it's that defects can be harder to see, and spread faster. This gives it the reputation for catastrophic failures - some of that reputation deserved. Also, it probably depends just how tight the manufacturer pushed the engineering tolerances of the material.

CF developed for consumer applications should be fairly flexible. I don't know if I'd trust a carbon frame after any decent crash, though.

As for UV: I don't think it should be especially susceptible. The fiber itself shouldn't be damaged. Effect upon the polymer impregnated in the carbon might vary with the breed, but it shouldn't penetrate beneath the surface.

n4zou

+1
Carbon fiber bike frames are for racing or for people that feel the need to sport the latest fad. Commuting is rough on a bike. Would you purchase a Corvette as a daily driver? Most people that must live on a budget and work for a living would never even consider purchasing a Corvette or other high performance sports car as a commuting vehicle. Why purchase a Carbon fiber bike for the same purpose? Considering the hard knocks, dings, and abuse a commuter bike must take a better choice would be a cyclocross or even an off road bike fitted with slick tires would be better. A steel or aluminum frame can be nicked and dinged with no structural damage done. If you feel you really need a "fashion" bike to commute on go with a Merlin. https://www.merlinbike.com/2006/classic/
A titanium frame is comparable in weight to a carbon fiber frame, will take dents and dings without structural damage, no paint is required, and is the material carbon fiber riders aspire to use after damaging there carbon fiber frame.

Torrilin

Carbon fiber (like any other composite material) can work very well, if it is appropriately engineered and tested. Exceeding spec in any way will cause failure. Failure will not always be catastrophic, but if you don't know what to look for, you may miss the signs. Spotting a composite in failure mode can be tricky.

Since bike manufacturers don't talk about how they spec a carbon fiber component, how they test it, and they don't explain what kinds of use may exceed spec, I get suspicious. Add in that certain sorts of carbon fiber components are ones where using it just doesn't make sense, and I get suspicious. The usual descriptions of how bike carbon fiber failed simply don't match with the normal [*] catastrophic failures I've seen, and I'm just not comfortable with that on a commuter bike. It's great stuff when used appropriately, and I do not believe that *my* cargo/commuter bike is an appropriate use. Your mileage will vary based on how you use your bike.
[*] If you are exceeding spec on a part deliberately, you expect catastrophic failure. This happens a lot when you're testing a CF component (or anything else really).

mattm

carbon frames don't have eyelets do they?

even if they did, i'd think you'd want something more on the comfort (read: steel) side than on the speedy side.

dwainedibbly

I'd worry about locking up a carbon bike, day in, day out. You'll inevitably get minor scratches & dings from the rack you're locking to and that's how carbon failures can begin.

Personally, if I ever come into a nice sum of money that I can spend on a commuter, I'm going with titanium.