O.B.Cyclist

To avoid being run over, I took a curb at full sprint last week. From roughly 20mph the front wheel completely stopped on the curb, I flew like superman, and the bike landed on top of my back. Front wheel destroyed. My bike is a Trek 1.1 which has a carbon fork. The bike shop inspected the fork and declared it safe. I'm pretty ignorant of bikes but I've heard of carbon cracking when crashed and then suddenly failing catastrophically sometime later with no warning.

Should I trust the fork after it pole vaulted me and the bike at 20mph? It was a violent hit.

jsigone

sounds like excuse to buy a new bike.....

stevel610 

How much is your medical insurance max out of pocket. (Mine is currently $600 for an ER visit.) Figure if you would rather pay it on to the bike shop or hospital.😉

Kobe 

If the impact was enough to ruin the front wheel, I would figure there was a decent amount of stress on the carbon. You might not see it, but it COULD be there. It would always be in the back of my mind.

randomgear

Check the downtube as well, a few inches back from the headtube - it takes a lot of stress during a front impact. Might be fine to ride, after all the wheel collapsing blunted the force of the impact to the frame and fork. Know any carbon frame builders in the area, they might be able to do a real check.

Milton Keynes

A year ago in October the bearings in my front wheel froze up, the skewer broke, I lost my front wheel and I went down, breaking my hand and kissing the pavement. That is not an experience I ever want to relive, so I'd get a new fork just to be on the safe side.

base2 

If the front wheel remained intact, the force of impact would have had to go somewhere. Likely into the fork & the rest of the bike. It seems to me the front wheel acted like a fuse, failed catastrophically & isolated the force of the impact from the rest of the system.

If you're looking for an excuse to buy a fork, go ahead. But, with the bike shops "ok" it's probably not necessary.

WoundUp makes good, no nonsense carbon forks in a broad range of specs. Not light by carbon fork standards. Strong. Manufactured in Utah, if that matters to you.

randallr

When the bike shop looked at the fork and pronounced it safe, did they just look at it visually, or did they do some additional types of inspection?

TugaDude

My concern is whether they are even qualified to render an opinion in the first place. Liability being what it is, I have a hard time understanding why they'd even comment. The correct answer, to me is, "we can't tell anything by a visual inspection of the fork. If you are concerned, you probably should simply replace it. Otherwise, the manufacturer may agree to take a look at it and determine whether it is fit for riding or not." That's what I would have done.

A visual inspection is next to useless. Especially if you aren't educated on what to look for.

I say replace it.

cyclist2000

Just replace it. An Enve carbon fork is only around $450, I'm sure that you can find something more economical. At high speeds a fork failure or front wheel failure is the worse scenario. Medical bills from my big crashes are a lot more expensive than $450.

tim24k

For peace of mind I would replace the forks.

georges1

Change the carbon fork and replace it by one with a steel pivot

Kontact 

Companies like Ruckus and Calfee can find damage a bike shop can't with scanning equipment. If the bike is nice, I would have both the frame and fork scanned.

If not, you can roll the dice that the wheel absorbed the impact. But you'll feel pretty dumb if the front end fails on a descent. Especially since you've posted this in the clydes forum and are already stressing the bike more than someone 120 pounds would.

HIPCHIP

I’d pull the front wheel, lay the bike on its side, and push and pull and twist on the fork legs individually and see if there was anything that stood out. If everything feels solid then try riding around slowly for awhile and see if there are any weird squeaks, etc. If everything seems good you are probably safe. Sounds like the front wheel took most of the impact. If you are still worried then just replace it.

Kontact 

This process will not reveal stress cracks in carbon.

stevel610 

What did you wind up doing?

grumpus

Never posting again, apparently - I wonder if the fork got him.

redshift1

While not directly related to the possible fork damage question, I observed something about a week ago which has amazingly left me in no doubt what to do if ever I am heading into a curb ( for whatever reason. )

A cyclist travelling fast ( I'm estimating 30 km/h ) on the road was obviously in no mind to slow down and wait for his turn to join the cycle path at the conventional point. Instead he continued with unabated speed square on to an upcoming curb and just when I thought he was an amateur about to subject his bike to a big impact ( whether he made it over the kerb or not ), he performed the most effortless lift of the entire bike ( up about 4 or 5 inches ) and silently slid over the curb as if it wasn't there.

Of course you need to be using clipless pedals and it's best to do a few practice "jumps" on the flat to get the feel of it.

I am pretty sure I will remember to do this in future if ever faced with an involuntary "kerbing" as it left quite an impression on me and most likely would save bike and possible limb. Worth doing as unlikely to do anything but improve the outcome.

base2 

"Bunny hop."
It's cool for manhole covers, speed bumps & potholes,

stevel610 

As someone else said, the term is "bunny hop". Youtube it for instructions. Don't need clips btw, just good technique.

grumpus

Tell that to the people who do it with flat pedals - clipping in is considered by some people to be cheating. Think about riding up a kerb by leaning back to lighten the front wheel, then leaning forward to lighten the back wheel as you roll up the bump. Then do it faster while crouching and jumping - that's the simplified version of how to bunny hop.

Trakhak

You'd better practice on level surfaces for a while before trying curbs/kerbs.

redshift1

"Bunny hop".

Yes that's the term I now vaguely recall from somewhere.

I won't actually be jumping any curbs as I ride just for the exercise, mental health, etc. benefits. And particularly as my next bike is framed with 531 Pro ( and I'm 85 kg ), I won't be risking the frame and forks from a mis-timed curb jump.

My point was that seeing how effortlessly that rider I saw lift his entire bike over the curb, that there is an alternative to running square on to a curb, if forced to like the O.P.

After having gone over the handlebars of a dirt bike travelling about 40 km/h a few years ago, when the front wheel was "stopped" by an approx. 4 inches diameter gnarly branch across the path, I can understand the OP's predicament and resulting accident. I would have sworn that wheel was going to roll over that branch...

Lifting the front wheel of a bicycle even a couple of inches would substantially reduce the risk of being "stopped" by the curb. It may still be a violent thump but with much less risk of damage and injury. Looking side on to a bicycle front wheel, the difference in the approach angle of the tyre to the curb at a height of 4 inches cf. 2 inches, is very apparent.

Of course, remembering to lift the front, even clumsily, in the heat of an accident situation will be a major issue for riders who haven't thought about it previously or practiced at least some.

I'll be practicing a bit on the flat but don't intend adding jumping curbs to my daily riding journeys. And of course, I'll keep up the defensive riding to avoid the curbs in the first place .