Question: I see pictures of gorgeous carbon bikes from Santa Cruz and Ibis and everyone else, but I am neither svelte nor graceful. How fat is too fat for carbon fiber?
Answer: A few companies–most notably road wheelset manufactuers–do list recommended weight limits for specific products, but most frame manufacturers tend to side-step the issue with ambiguous wording, or no information at all. Current carbon fiber frames do have the potential to be stronger than metal frames in almost every way. The traditionally bullshit marketing term “stronger than steel,” is actually true when it comes to carbon fiber; it really is incredibly strong, and its basic construction method tends to be very reliable and extremely consistent. You can put exactly as much material precisely where you need it on a carbon fiber frame, and that precision makes for huge improvements in strength and stiffness. Most clydesdales assume carbon fiber is going to be weak and flexy simply because it’s so light, but even crazy-light frames like the Santa Cruz Blur XC and Tallboy genuinely feel stiffer and more solid than their aluminum counterparts. So modern carbon fiber (unlike the Scott Black Magic handlebars I broke every third ride in the early ’90s–they would keep warrantying them for as long as your suicidal tendencies persisted) is very good. In fact, the only area in which a well-made carbon fiber frame is at a disadvantage to more traditional metal frames is impact. With a few glaring exceptions carbon fiber can’t take a punch.
In most cases, the real question isn’t, “Do I weigh too much for carbon fiber?” but rather, “Do I crash too much for carbon fiber?” And it’s not only how often you crash, but how unpleasant those crashes tend to be. There are many shades of “not graceful.” Classifying yourself based on your last three bails will tell you more about the lifespan of your future carbon fiber frame than your weight alone will ever reveal.
Figuring out which specific type of trainwreck best describes your riding can be done using personality tests like the Minnesota Multiphasic Personality Inventory or the Myers-Briggs indicators, but looking around on the Internet, I found an even better personality test called “Character Alignment” from an organization called Dungeons and Dragons. Here’s a simple guide to help each of us determine his or her own level of personal destructiveness.
Chaotic Good
You mostly only hurt yourself.
Carbon Fiber for you? Might as well.
Bonus points for: Sand
Neutral Good
Ambivalent about authority, but not capable of achieving “damage velocity.”
Carbon Fiber for you? You’ve earned it.
Bonus points for: Getting your mom’s attention.
Lawful Good
Your bike will last forever.
Carbon Fiber for you? Yes.
Bonus points for: Flip-flops.
Lawful Neutral
You respect gravity, but are rightfully suspicious of higher powers.
Carbon Fiber for you? No.
Bonus points for: Getting up in the morning.
Just Neutral
Whatever. I’m getting a beer.
Carbon Fiber for you? No.
Bonus points for: Jeans and a t-shirt.
Chaotic Neutral
Society says you can’t jump in lycra. Fuck that.
Carbon Fiber for you? Unfortunately, yes.
Bonus points for: Sticking it to the man.
Chaotic Evil
You are a tool of pure and total annihilation.
Carbon Fiber for you? Nope.
Bonus points for: Thinning the herd.
Lawful Evil
Experienced enough to investigate situations that will truly, utterly destroy a bike.
Carbon Fiber for you? No.
Bonus points for: Riding our concussions.
Neutral Evil
You really only care about yourself, and you’re pretty awful even at that.
Carbon fiber for you? Yes, because it’s sexy.
Bonus points for: Sass.
Hopefully, this helps clarify things. When it doubt, stick with chromoly.