codyB

I just got a nice used road bike in perfect condition with an aluminum alloy frame and a carbon fork, but not carbon steering tube. I will be riding this bike over a TON of potholes and bumps, but hopefully never curbs, and 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?

livedarklions

Not very likely, and keep the fork if you can live with the very small risk, or get a new one if you can't. I've hit potholes at a lot faster than 18 mph on my carbon fork, and no problems. Failure is an abnormal occurrence unless it's been damaged by a previous accident.

bakerjw

I ran a no name chicom carbon fork on a bikepacking rig. It took all kinds of abuse without any issues at all. If the bike is a name brand bike, you should be ok.

But... Hitting pothole will damage rims, cause pinch flats and could put you down hard. Avoidance is the key.

codyB

Thanks. I'll keep it then.

ridelikeaturtle

Why are your forced to hit potholes?

codyB

In my city there are innumerable potholes, or strange bumps, some lines of potholes that span the whole street. Often when a car is passing me I will come up one a pothole that, were the car not there or if I had enough space, I could avoid, that I'd have to come to a full stop and wait for the car to pass to avoid. It's ridiculous and everybody hates it. I live in Buffalo NY, U.S.A. by the way.

ridelikeaturtle

You need a mountain bike!

codyB

They're way too slow for my liking. Maybe I could put some thinner tires on a fully suspended mountain bike but still in my experience theyre usually heavier. I don't think I've ever seen thin wheels on a mountain bike and there's probably a reason for it.

SactoDoug

I have never broken a carbon fork. I was hit by a minivan that shoved me into the curb. The front wheel had broken spokes and was bent badly but the carbon fork did not break. I did not reuse the fork because it skidded across the sidewalk which gouged it down to the carbon fibers. That damage would have ruined any other fork too.

bpcyclist

So far, so good.

livedarklions

If you do any serious amounts of riding in a northern US state, you're bound to run into some pretty horrible potholes. Infrastructure maintenance is not terrific in this country, and winter's effects on tarmac and concrete accumulate.

Feldman

If peace of mind is worth a couple of hundred bucks, Ruckuscomp in Portland can ultrasound carbon frames and forks to check for cracks undsr the surface. Ruckuscomp.com, I think.

ThermionicScott 

Skinny tires for speed is old thinking. Now there are lightweight and fast tires in 2"+.

mr_bill

Just saying the obvious, but putting a 2”+ ”lightweight and fast tire” into a fork (or frame) without adequate clearance turns a “nice used road bike in perfect condition with an aluminum alloy frame and a carbon fork, but not carbon steering tube” into a large and awkward paperweight.

On the other hand, since such a road bike is no longer roadworthy, no worries about potholes, or forks.

Sometimes one’s gotta know their limitations.

-mr. bill

ThermionicScott 

I was only referring to the hypothetical mountain bike in the post I quoted.

I have no use for carbon road bikes with inadequate tire clearance.

mr_bill

I suppose when you have a hammer, all the world looks like nails.

Oddly, people ride all kinds of bikes, even in Buffalo, New York.

-mr. bill

ljsense

The only time I have been able to break a carbon fork was when I hit a parked utility truck at somewhere north of 25 miles an hour. The lid of my water bottle shattered in the crash. Front wheel was destroyed. I broke some ribs and had a big contusion on my jaw.

The fork was cracked on one leg. I took it off the bike, and later put a wheel back in it and used it to trolley lumber for a project. Even badly damaged, with a big crack through the front of one fork leg, it held its end up over rough forest paths when the load was a few hundred pounds.

Carbon forks have handled millions of miles over all kinds of conditions. Every cyclist racing the spring classics over cobbled roads rides a carbon fork. Severe front impacts can break them as well as they would any fork.

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. The potholes might steal your identity and lead you to financial ruin. They could publish a lightly fictionalized memoir that puts you in a terrible light. They may vibrate your arms in such a way that you'll get double arm cancer, which happens to have no ribbon to honor its victims. Any of this could happen. Stare into the abyss of a pothole and the abyss stares back into you.

nomadmax 

I was gonna say glasses

I'm kidding, just kidding As mentioned above, based on what you describe I wouldn't worry too much about the fork.

ThermionicScott 

You're full of platitudes today. Got anything helpful for the OP?

mr_bill

Yeah, enjoy your bike and don't listen to people yapping on about 2"+ tires.

-mr. bill

tagaproject6

If there are that many potholes as you claim there are, I doubt you will be hitting anything at 18 mph. And if you do hit a pothole at that speed, the carbon fork is the least of your worries.

codyB

There are some streets with minimal potholes but the majority are, in certain stretches, riddled with them but even in those areas I've hit potholes at 22 mph or more.

codyB

It might force me to watch as it cuckolds me.

79pmooney

"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

codyB

Are me and 79pmooney the only people in this thread who live in the U.S. Northeast?