Touring - carbon forks possibality of snapping?

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dooodstevenn
01-11-10, 05:18 PM
i know alot of people misjudge carbon forks saying that they arnt the strongest thing out there, but will they snap after having all the extra weight on it? bike weighs in at 19.5 pounds unloaded with road wheels, after putting on some wheels 10 wheels gave a link too it'll probably be a little more obviously, i weight about 200 lbs, with more weight what are the chances of the fork snapping?
John Nelson
01-11-10, 05:31 PM
I've seen many pictures of snapped carbon forks, but all of them were due to some sort of impact and didn't just snap while riding along.
But I certainly would not mount a front rack to a carbon fork, and I would inspect it very, very carefully after any crash. Most wheel manufacturers specify a maximum weight, but I don't think your 200 pounds is going to exceed that.
Carbon fiber is very strong stuff, but if it's chipped or damaged in any way it is vulnerable to sudden, catastrophic failure at the point of the damage. So a new pair of carbon forks would be fine for touring or a heavy rider, but if they got chipped or gouged badly in a crash (or by being thrown in the back of a truck with other bikes, or similar rough treatment) they would be liable to fail later on.
dooodstevenn
01-11-10, 06:20 PM
alright, ill stop stressing out about my carbon fork then haha thanks
10 Wheels
01-11-10, 06:24 PM
alright, ill stop stressing out about my carbon fork then haha thanks
My Felt has carbon forks
http://i256.photobucket.com/albums/hh187/10wheels/First%20Felt%20F85%20Ride/F-85FirstRide048.jpg
Ding Ding
01-11-10, 07:13 PM
my cousin makes carbon fiber water skis and he once told me if you get in a wreck sometimes there will be little noticable damage to the human eye that you actually have to xray your bike to see the true damage
kayakdiver
01-11-10, 07:22 PM
Don't worry.... be happy.... :)
sstorkel
01-11-10, 09:15 PM
Carbon fiber is very strong stuff, but if it's chipped or damaged in any way it is vulnerable to sudden, catastrophic failure at the point of the damage. So a new pair of carbon forks would be fine for touring or a heavy rider, but if they got chipped or gouged badly in a crash (or by being thrown in the back of a truck with other bikes, or similar rough treatment) they would be liable to fail later on.
Carbon fiber runs into problems if you cut or break the carbon fibers. Chips or gouges in the paint or clearcoat won't do anything to the underlying strength for the fork. Throwing a carbon frame into a truck with other bikes shouldn't be a problem. Crashing into solid objects (walls, cars, the ground) may be. Often, problems are readily apparent if you know what to look for. Those who don't know what to look for, crash, then keep riding anyway are usually the ones who end up with "explosion" stories.
To the OP: my loaded touring bike weighs 51 lbs, I weigh 170lbs, and I use a cheap (read: Nashbar) disc brake-equipped carbon fiber fork. Haven't had a problem yet and I don't expect to have any in the future...
Was on tour last year when this guy coming into a rest stop with a carbon fork, he slowing down to make the turn into the driveway and his front fork snaps in half, he took a spill but it could have been a lot worse, we had a lot of hills that day.
hybridbkrdr
01-12-10, 04:26 AM
Don't worry.... be happy.... :)
Yes, be happy until the fork explodes and injures you while it happens. No, I'm just kidding. But, to me safety is more important. I'm too scared to ride something that could randomly explode on you and injure you.
sstorkel
01-12-10, 09:58 AM
I'm too scared to ride something that could randomly explode on you and injure you.
You should be more worried about your car randomly exploding. Carbon only explodes if you're stupid. I've ridden carbon frames and components for at least 15 years and never had a problem. And believe me: the stuff today is much better than the stuff from 15 years ago!
acantor
01-12-10, 10:53 AM
I had a carbon fork on my touring bicycle for several years, but got rid of it after reading accounts of catastrophic failures with no warning.
The only advantage of carbon forks that I am aware of is that they save weight. But assuming a saving of 300 or 400 grams over steel, there are many ways to accomplish the same thing. For example, jettison one or two items of clothing. Mail souvenirs home instead of carrying them. Avoid bringing duplicate tools. Carry only one paperback book, and trade it in or give it away when you are finished. Throw away maps that you no longer need. Or, more radically, don't worry about it. On a loaded touring bicycle, a couple of pounds extra is hardly noticeable.
HardyWeinberg
01-12-10, 11:14 AM
How do they figure those jetliners (http://www.youtube.com/watch?v=9qV8tJYJDIg&feature=video_response)won't shatter in midair?
I know the CF speedboats are not great in collisions (at least w/ old school steel (http://www.youtube.com/watch?v=mWL82aLjRgM)). But the America's Cup boats do OK. I don't know how many of the DNFs are due to CF failure.
Is it just crappy CF on bikes? Or a greater sample size, there's 80 gazillion CF bike parts out so of course there a lot of noteable catastrophic failures?
foodman
01-12-10, 11:25 AM
Order a cheep steel touring specific fork with rack eyelets from your LBS. It will give you some piece of mind and make your life easier when it comes to finding a front rack.
MichaelW
01-12-10, 12:46 PM
Fuji used to make a serious touring bike with a carbon fork but it wasnt an ultralight racing fork. The weight saving over a high quality steel touring fork is not huge.
Not all steel forks are the same.
"But the America's Cup boats do OK..."
Not really, a few races back, the whole front of one boat came off. And a few years back in a different race, virtually the whole offshore fleet blew up because of bad weather. That was an interesting case because the boats in question where designed for combinations of onshore and offshore racing. Sponsors no longer felt like supporting two whole fleets of boats. The result was the mass disintegration of the fleet due to the unusual conditions. Sorta like racing tech moving to the touring field.
Overall though, I think you can do great with carbon, the problem is design. Steel may weigh too much, but at least the design is simple. With carbon it normally takes a while till they figure out just how best to employ it. When they do it becomes the bulletproof leader of the field. Arrows are a good example of that. They get slamed into target at 300 fps. Originally they were fragile, now they are the tough use choice of many. I am guessing that nobody is actually doing much R&D with carbon touring forks.
The other bad thing about them is that the metals in carbon forks tend to be aluminum, which means you get the nasty quirks of that metal. Aluminum in frames sounds good to me, but I don't really want it in stuff like drops, brake posts, or steering tubes.
I agree with those who have said there seems little reason for it in a touring bike. I've always wanted to build a frame for that Nashbar 26" fork.
ryandood
01-13-10, 02:49 AM
On my last mini trip I hit a car while riding. I shattered the rear window of a minvan with my head/helmet and got a small scrape on my arm. I thought my bike was fine but I later noticed that I had bent my steel OE fork on my CrossCheck. I probably shouldn't have continued but was able to go on for two more days without any big issues (besides the gnarliest toe overlap you've never seen). Had it been a carbon fork, my trip would have been done.
You can think of it that way or in the sense of, if it were to happen to you when you were in the middle of nowhere w/ a cracked carbon fork instead of a bent (but still ridable) steel fork. I'd say leave the carbon for the more spirited riding, IMO.
kayakdiver
01-13-10, 07:26 AM
ryandood,
A carbon fork may have broke... Might not. It all comes down to how it's built. They build mountain bikes out of carbon now. It's all about a balance. Strength and weight.
Super light steel frames and also titanium can be very fragile when weight becomes a priority over durability and strength. Finding that balance is the issue.
I ride my now 6 year old carbon frame with as much concern for an explosion as I do my steel and alum frames.
Well built is well built. Nothing wrong with either if done correctly. My 2 Cents.
sehsuan
01-13-10, 09:05 AM
www.bustedcarbon.com
just came across this site lately...
I was in a 4-person pace line pile up a few years ago. results: 1 broken carbon fork and one broken wrist (not mine).:( However, three other carbon forks as well as the seven other 7 wrists were OK. ;)
zonatandem
01-13-10, 10:49 PM
25,000+ miles now on our full carbon fiber tandem (including the fork). No issues.
Have broken a steel fork (on a tandem) and 2 steel tandem frames.
Any material can fail eventually.
If your touring involves a lot of vehicular transport, then I'd be worried about carbon damage during that transport than of too much weight on the fork. The rare occasion that I've toured, my bikes have ended up with a fair bit of mostly superficial fork damage. Recently, two weeks of biking in China saw some pretty deep gouges out of a fairly sturdy set of suspension forks accumulated during bus and truck transport. Had these forks used carbon lowers, they'd be on a junk pile now.
sstorkel
01-15-10, 10:08 AM
Had these forks used carbon lowers, they'd be on a junk pile now.
Maybe, maybe not. You have to damage a huge number of fibers to compromise the integrity of carbon fiber...
Dave Nault
01-15-10, 11:51 AM
If you're going to use a carbon f ork for touring, make sure you buy a heavier one. This is not the place to be a weight weenie. CF forks can withstand quite a bit of loading provided they are made for that. On road bikes, the emphasis is on light weight and to accomplish this the laminate schedule is also light where on a cross bike for example, they would use a more robust laminate schedule.
Just a note: AC boats are designed and built to opperate in a very narrow peramiter of wind and water conditions to save as much weight as possible. (Boat builders have a mind set that if it didn't break then it was built too heavy and I can speak from a first hand perspective on that ) When boats come apart it's because they exceeded that designed peramiter, not that the carbon fiber was weak. Many AC trial horse boats are made and tested before the one that is eventually raced is built so it's not unusual to hear of a hull failure because they are always testing the hairy edge of how light it can be built but really it has zero to do with the material they are being made of.
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