I don't like carbon fiber on mountain bikes.
I've personally seen 3 broken carbon seatposts.
In 2007 a carbon handlebar snapped off (due to improper installation) while a guy was riding the Crest. He crashed so bad he had to be LifeFlighted off the mountain. (Read all about it, with photos.)
On a local group road ride a fellow broke his carbon bars while down in the drops and somehow managed to not crash.
The Busted Carbon blog shows a whole parade of broken carbon fiber components and frames. Mostly road bikes, but plenty of mountain bikes too.
I wasn't happy to see this photo - I hope my HiFi seat stay doesn't break like this guy's.
Carbon fiber composites have incredible strength for their light weight. But if the fibers are cut (from an impact say) they loose a lot of strength. Manufacturers put a thick protective coat over the fibers, but it's not impenetrable.
When carbon fails, it usually does so catastrophically. Metal will often bend first before snapping.
For me I'd rather go with metal and not have to worry about finicky carbon.
So tonight I replaced two carbon component from my mountain bike with good old metal parts.
Bye, bye carbon seatpost.
Hello Thompson aluminum seatpost.
So long carbon handlebars.
Welcome metal bars. These also have some riser and sweep back which I want.
I kept the carbon steerer tube cap. Not much risk there.
I'm keeping the carbon cranks for now. I don't think they're much risk, because my last name isn't Holley. I have a metal Shimano crankset I'll swap in someday.
(But these cranks do have a nasty habit of loosening chainring bolts. I've never had this problem before. Time for some Loctite.)
Corner Canyon Ride
Zipped over to Corner Canyon for a ride after work yesterday.
The Rush trail has been reworked and open for a while and I've been itching to check it out. I went up Canyon Hollow and down Rush. I really like the changes. More flow and more fun. Rush also makes me painfully aware I'm not a good cornerer. And I often clunk over bumps and jumps. So I'm glad to have Rush to help me get better - it will be a good skills improvement trail for me. The dirt is still loose, especially on the berms, but a good rain should make it hard and fast.
Next I mixed it up and went up Ghost Falls and down Canyon Hollow (thanks for the reminder, dug). I'd been down Canyon Hollow last year and liked it, now it's even better as the trail has worn in. And Ghost Falls is an entertaining climb, although I was constantly on alert for riders bombing down.
Saw lots of Sego Lillies in bloom in the sunny, open spots.
Saw more critters on the trail than usual. And I mean "on the trail." 4 squirrels, 1 lizard, 1 snake and a deer I would have T-boned if it hadn't bounded off the trail.
It was pretty hot and the trails are getting dry and a bit more loose, but it was still a satisfying ride. Viva la Corner Canyon!
The End
2 years ago
7 comments:
I rode CH and GF last night, saw one owl and at the top parking lot saw 2 sets of eyes. They didn't have the green/yellow color like the set I saw last year so I am assuming they were deer.
That UMB broken bar was an obvious case of overtightening the brake caliper onto the bar. Carbon is great, and not a problem on any bike, dirt or road, provided you use a torque wrench properly.
SBJ - You are correct on the UMB broken bars and I have added a note about the improper installation in my post, in case people don't follow the link to get the whole story.
Perhaps my anti-carbon tendency makes me a Luddite, but I feel it's mostly rational with some amount of personal preference.
I took 2 composite classes in college and worked for a composites company. Perhaps knowing more about carbon has made me unreasonably leery of it - like an orthopedist who won't buy his kids a trampoline. But I also have some eye-witness experiences to back me up.
I feel more comfortable with metal. I don't care about a little extra weight (my stomach makes that obvious). I also like that metal will often bend instead of breaking, where carbon almost always fails completely if it goes. And I don't want to hassle with a torque wrench and keeping an eye out for damage.
Are these big, serious, unmanageable issues? No, but enough to nudge me to prefer metal.
Glad the Thomson seat post worked.
tallsteve
After riding Corner Canyon and heading home. Over by the holding pond I ran into a family of Skunks. 5 of them. I thought for sure I would get sprayed. First time I have seen skunks. I have almost hit deer on that trail several times. They use the bike path at night. Kind of funny to watch.
Kris: full disclosure--I run a Thomson post on my MTB and didn't even consider buying anything else. Thomson posts are designed to bend and not break when they fail.
Sadly, lots of other alloy parts are not. I've seen more instances of aluminum breaking than carbon, but that's also a function of having more exposure to aluminum parts than carbon fiber. But failure by breakage is not the exclusive domain of carbon fiber.
The problem with aluminum is that there's not fatigue limit, so it becomes a question of when, not if, it will break due to metal fatigue. Steel isn't subject to metal fatigue, but it's heavy. Sabrosa John says "who cares?" but when you consider that Brad's single speed weighs 24 pounds while Elden's weighs 18, at some point you have to care if your intention is to go fast. But then again, lots of people spend lots of money trying to get a light bike when they're neither racing nor training to race in a manner to capitalize on the weight advantage.
Bottom line is that there's no perfect material, otherwise it and only it would be used exclusively.
Just so you know I broke that bike 4 times 2 of which were metal parts.. i'm going back to hardtail full carbon if that one breaks I will most likely sell the frame and get TI frame
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