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Fear of carbon fork breaking on potholes

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Fear of carbon fork breaking on potholes

Old 10-08-19, 06:54 PM
  #26  
MikeyMK
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There's nothing wrong with suggesting that someone riding a road bike in pot-hole city is on the wrong bike. Even on a forum full of die-hard roadies.

But if the OP's happy with smashing a twiglet road bike over potholes at 25mph, and isn't open to alternatives, then there's little else to suggest.



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Old 10-08-19, 08:24 PM
  #27  
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Originally Posted by codyB View Post
Are me and 79pmooney the only people in this thread who live in the U.S. Northeast?
No, 79pmooney used to live in the northeast. Several of us live in potholandia.

Suggest that rather than worrying about your fork, you learn when and how to get out of your saddle, and also learn how to repair flats.

And ignore the wrong bike crowd. And the wrong tire crowd. And the wrong....

-mr. bill

Last edited by mr_bill; 10-08-19 at 08:56 PM.
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Old 10-09-19, 12:14 PM
  #28  
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Originally Posted by codyB View Post
Are me and 79pmooney the only people in this thread who live in the U.S. Northeast?
Ahem.
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Old 10-09-19, 12:29 PM
  #29  
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Originally Posted by mr_bill View Post
No, 79pmooney used to live in the northeast. Several of us live in potholandia.

Suggest that rather than worrying about your fork, you learn when and how to get out of your saddle, and also learn how to repair flats.

And ignore the wrong bike crowd. And the wrong tire crowd. And the wrong....

-mr. bill
I ride some pretty damn bumpy roads on my 25mm, urban and rural, and really there isn't that big a difference between them and my 36mm as long as I get off the saddle. For me, the handling on a street is much better with the 25s, so I'm able to avoid potholes with a lot less notice as well.

I had a plastic fork break in two once, but I was using it to hold a tough steak in place while trying to cut the steak with a plastic knife.
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Old 10-11-19, 10:01 AM
  #30  
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The people suggesting a fatter tire are offering good advice, because when you hit a pothole, the sequence of failure is: tube --> tire --> rim.

In other words, first you'll pinch flat. If it's worse than that, it might cut your tire or flat a tubeless tire. If it's worse than that, it might crack or dent your rim.

If it's worse than that, it might throw you over the bars after damaging your front wheel. But your fork will still probably be fine.

If you've ridden the route and are getting by with your current tires, there's no reason to worry about the rest. They're the canaries in the coal mine.
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Old 10-11-19, 12:32 PM
  #31  
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Originally Posted by codyB View Post
I'm worried about the carbon fork snapping as I hit a pothole at 18mph. I'm thinking of changing to a different material fork for this reason because again I am often forced to hit a lot of potholes, but can anybody tell me how likely a serious breakage is to happen while riding or what the best course of action would be?
Carbon is extremely strong. Changing to a different material won't improve the durability of your fork.

Also, the notion that carbon parts snap without warning is mostly a myth. Like metal components, they fail progressively. If ever your steering starts feeling soft, stop riding. You likely have a damaged steering tube that may soon break off.
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Last edited by terrymorse; 10-11-19 at 12:39 PM. Reason: added "snap without warning" myth
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Old 10-16-19, 11:32 PM
  #32  
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Learn to bunny hop.

Also, I regularly ride an 8 year old, all carbon crit bike on dirt and gravel. It ain't the right tool for the job, but it can be fun for a while.
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Old 10-20-19, 08:31 PM
  #33  
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I live in the rural Northeast and I'm familiar with the urban streets of upstate NY. Believe me when I tell you this but the infrastructure and roads are measurably worse here and I ride carbon forks without anxiety. If anything will go out on my bikes from the abuse, it's the wheels. I ride a 35c up front and the advice for wider tires is a good one. You will actually ride faster with them on dilapidated asphalt(I think 28 on up is ideal in these situations. I concur 2" is excessive unless you plan on doing double duty on singletrack). Our "potholes" consist of 3 inch wide holes that stretch a good 30 yards up the road. Some are even large enough to swallow truck tires. Road repairs are done sloppily by the lowest bidder and no attempt is made to blend the edge of new sections with the older asphalt.

And yet, I have no concerns over using carbon forks and in fact much prefer them.
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Old 10-21-19, 06:53 AM
  #34  
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Originally Posted by Jeff of Vt View Post
I concur 2" is excessive unless you plan on doing double duty on singletrack).
I lost a 215mm tire and a 17x7 rim to a pothole.

Personally, I think 2" wide is underkill. Which is kind of the point. You can't wide your way out of pothole trouble, but you can ride your way out of pothole trouble.

-mr. bill
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Old 10-21-19, 09:01 AM
  #35  
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Originally Posted by mr_bill View Post
. You can't wide your way out of pothole trouble, but you can ride your way out of pothole trouble.

-mr. bill
I know it's actually a tricycle, but this seems to work for widing it out:


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Old 10-21-19, 09:48 AM
  #36  
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Originally Posted by 79pmooney View Post
"Carbon forks have handled millions of miles over all kinds of conditions." Yes. But carbon forks have also snapped suddenly at the crown/blade or crown steerer interface. I've had a (non-steel) fork break on me in that fashion. Trust me, it is the one bicycle failure you do not want to happen in this lifetime or your next.

"Every cyclist racing the spring classics over cobbled roads rides a carbon fork." Yes also. But they ride those races on new or near new forks.

"If you worry about a pothole taking your fork out, you might as well worry about the pothole breaking your handlebars, folding your rim, or causing your frame's headtube to separate." All of those are less catastrophic than a CF fork braking at the crown. I bent an aluminum handlebar 30 degrees riding into a New England March pothole (with acar beside me). Trashed many rims on potholes, riding almost all home.

Headtubes and the headtube/downtube/toptube joints are part of the critical path (as are the fork and steerer and the stem and bars). Complete failures there almost always involve going over the bars and landing hard, usually on head or shoulder. I've done my lifetime's worth of crashes so I will limit the materials I use there to metals that are likely to bend before complete failure or give warning. Where I cannot, I use cheaper materials and replace those parts fairly often. (Cheaper means I am not "wedded" to getting the most out of it.)

Ben
This. I've buckled rims on potholes. And once hit a curb at speed, which resulted in the headtube snapping off at the top and down tubes. But the fork was fine.
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Old 10-21-19, 09:59 AM
  #37  
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Originally Posted by livedarklions View Post
I know it's actually a tricycle, but this seems to work for widing it out:
Oops.

-mr. bill
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Old 10-21-19, 10:28 AM
  #38  
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However, in this crash, the fork didn't break!



-mr. bill
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Old 10-21-19, 11:22 AM
  #39  
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Originally Posted by mr_bill View Post
However, in this crash, the fork didn't break!



-mr. bill
That's a pretty good magic trick, the steamroller turned into a pub.
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Old 10-22-19, 11:18 AM
  #40  
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The OP has a valid worry. You can call it carbon fiber, but as I have always pointed out it is carbon fiber reinforced plastic. The main weight of any so call CF product is plastic. Plastic shatters and breaks.
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Old 10-22-19, 11:35 AM
  #41  
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Originally Posted by rydabent View Post
The OP has a valid worry. You can call it carbon fiber, but as I have always pointed out it is carbon fiber reinforced plastic. The main weight of any so call CF product is plastic. Plastic shatters and breaks.
That is like saying a Steel Reinforced Concrete wall is made of mostly sand.
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Old 10-22-19, 02:40 PM
  #42  
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Originally Posted by rydabent View Post
The OP has a valid worry. You can call it carbon fiber, but as I have always pointed out it is carbon fiber reinforced plastic. The main weight of any so call CF product is plastic. Plastic shatters and breaks.

You and the OP don't have a valid worry. You don't understand the engineering and manufacturing process based on your comments.

The OP doesn't have to worry about his carbon fiber fork shattering if he hits a pothole at 18mph. His tubes/tires are another thing and depends on his setup, the depth of the pothole, and its edge characteristics. He's a prime candidate for tubeless.
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Old 10-22-19, 03:23 PM
  #43  
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Originally Posted by hagak View Post
That is like saying a Steel Reinforced Concrete wall is made of mostly sand.
We should make our forks out of Purbeck stone.

-mr. bill
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Old 10-23-19, 01:13 PM
  #44  
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Originally Posted by mr_bill View Post
We should make our forks out of Purbeck stone.

-mr. bill
I tried that, but the mortar on the flying buttresses kept crumbling when I hit potholes.
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Old 10-23-19, 01:34 PM
  #45  
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Originally Posted by ab_antiquo View Post

You and the OP don't have a valid worry. You don't understand the engineering and manufacturing process based on your comments.

The OP doesn't have to worry about his carbon fiber fork shattering if he hits a pothole at 18mph. His tubes/tires are another thing and depends on his setup, the depth of the pothole, and its edge characteristics. He's a prime candidate for tubeless.
I used to build fiberglass racing sailboats. (Also trained as an engineer.) I understand more of the engineering and manufacture of carbon fiber parts than I would like. Knowing that fabrics are cut and laid up in a mass production facility by very lowly paid workers and that QC is near impossible except by destructive means doesn't give me a warm and fuzzy feeling. Yes, the odds of landing a bad one from a reputable company are small but the consequences of a fork failure are (at least in my eyes) completely unacceptable. (I've had it happen once. I do not want to live if it were to happen again. That simple.) So I will ride steel forks that can be inspected almost entirely by eye, have well known failure patterns and almost always give warning.

Ben
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Old 10-23-19, 03:48 PM
  #46  
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Originally Posted by 79pmooney View Post
(I've had it happen once. I do not want to live if it were to happen again. That simple.) So I will ride steel forks that can be inspected almost entirely by eye, have well known failure patterns and almost always give warning.

BEN
Since the OP likely doesn’t know, the death fork was cast aluminum with a steel steerer tube. It didn’t “almost always” give warning.

I can’t quarrel with your personal choice. Others have chosen bents. However, spooking others is unwise.

-mr. bill
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Old 10-24-19, 11:20 AM
  #47  
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So how far and how often do you ride your steel reinforced concrete wall???
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Old 10-24-19, 12:49 PM
  #48  
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I myself would never buy a used bike. One never knows if the seller is actually telling the truth wanting to get ride of the bike. Maybe it has been crashed, of course he will say no or it won't sell.

I have a bud who crashed his bike in a race. Took it in to get inspected. Carbon bars ended up snapping on a mountain descent. Scary but somehow managed to save it as only one side snapped off. Being his bike he knew it had been crashed but took the inspection's evaluation that it was in good condition.

That was his own bike. Trusting someone who wants to sell a bike? Not for me! Plus that voids the warranty.
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Old 10-24-19, 04:09 PM
  #49  
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Originally Posted by rydabent View Post
So how far and how often do you ride your steel reinforced concrete wall???
I'm pretty sure that I've ridden my carbon frame with carbon fork, carbon bars, carbon stem, carbon cranks, carbon rims, carbon seat post and carbon saddle rails more often than anyone has ridden any steel-reinforced concrete wall.

Over the past few decades I haven't had any carbon parts "shatter and break," as you have hysterically claimed. Again, and despite your fear-mongering, the OP doesn't have a valid concern.
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Old 10-25-19, 07:06 AM
  #50  
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Originally Posted by ab_antiquo View Post
I'm pretty sure that I've ridden my carbon frame with carbon fork, carbon bars, carbon stem, carbon cranks, carbon rims, carbon seat post and carbon saddle rails more often than anyone has ridden any steel-reinforced concrete wall.

Over the past few decades I haven't had any carbon parts "shatter and break," as you have hysterically claimed. Again, and despite your fear-mongering, the OP doesn't have a valid concern.
Review several threads on this forum. There are many threads about CF forks and bikes shattering. The OP does have a real concern. He might pay a severe penalty for light weight componets.
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