anyone ever try to pedal and go over the bars going UPHILL

[jimcav]

Had my weirdest mechanical ever JRA today.
short hill near start of my ride, about `14%, got out of the saddle, did about 3 revolutions, and crank became in less than a second impossible to push--but I was trying my hardest, and the entire bike rotated and i went face forward. Banged up both wrists and as I was rotating slowly over i saw my rear wheel hit the grass/bushes to the right of me--so I'm thinking by trying to continue to push the pedal it pulled the rear wheel out of the drops and flung it up and to the right?

So I suspect the rear skewer got loose, the wheel shifted as I stood on the cranks, the chain got stuck, either on cassette or crank rings, but I had no idea I could rotate my self over like that.

As I picked myself and the bike up, the chain was initially going across both 53/39, but not stuck--no tension since the rear wheel was off the bike. I put the wheel back on, did a shortened ride b/c my left wrist really hurt and it was hard to use brake or support myself on the bars.

Apart from being incredulous that this happened, i am wondering if I could have possibly stressed anything that I need to check or replace--don't want the chain to snap for example. The shifting on my ride was not bad, but a little off from before going over, possibly I stretched the cable a bit, and I guess this will be an opportunity to use my b-day present HAG for the first time?

Anything else anyone can think of?

[Peter P.]

Maybe the chain suffered a twist or bend in the process?

[Hilltopperny]

Is it possible the chain ended up caught between the spokes and cassette since you were climbing 14%? Then the chain released and the wheel flew off? Glad you didn't get too hurt!

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[Alistair]

I've done it mountain biking, but that was just me being awkward and not a mechanical. Steep climb with lots of roots, on my single speed, trying to muscle my way over a root, got too far forward, and went over the bars.

[Hindmost]

Rear wheel slid forward/left, momentarily stuck to chainstay, you launched yourself forward as crank froze/bike stopped. Check quick release and dropouts.

[BryanE]

Going up a small grade and I stood up to push my meager power and…..
pedal came out of crank and I went over the bars. Broken clavicle. Stupid human tricks.

[redir]

I would never expect that to happen either, that's odd, especially on a 14% climb.

[.RJ]

i saw that happen in a crit when a guy forgot to tighten his rear skewer after taking the bike off the trainer

[dgauthier]

.

[Mark McM]

Riders can go over the bar when the crank suddenly has no resistance (as when the chain breaks or derails off the chainring, or the rear wheel looses all traction), but it is odd that it should happen when the crank stops. But I guess depending on CG shift/momentum and muscle timing, its possible for the rider to "throw" themselves over the bars under high power whenever the cranks don't move as expected. Standing on a pedal with a moving crank is a dynamic balancing act, so it's quite possible to get thrown off balance when the crank suddenly stop/starts moving in an unexpected manner.

This isn't much different from sailors developing "sea legs". A "land lubber" may easily get thrown off balance on a moving deck, but a seasoned sailor can learn how to compensate for the deck's movement. That same seasoned sailor can feel off balance when they get to land, because they are so used to moving in reaction to a moving deck.

[bshell]

Originally Posted by Alistair

I've done it mountain biking, but that was just me being awkward and not a mechanical. Steep climb with lots of roots, on my single speed, trying to muscle my way over a root, got too far forward, and went over the bars.

hahahahaha, Identical. 2 times now.

[jimcav]

I wasn't in the easiest gear, this is more of a short kicker of a hill, with a 10% downhill approach to it--so I was in my biggest gear, shifted up the cassette a bit, then from the 53 to the 39, then pedaled a bit, then stood, and that was when it happened.

Since my rear wheel came out, I know the skewer had to be loose. I had a pre-B stay C40 where the rear skewer would loosen. Has never happened since, and I've had dozens of various combos of different bikes, varied wheels, various skewers. and I guess I need to get back in the habit of checking it. This bike was a relatively new to me forum purchase, so it was my 6th ride on her.

I will give the chain a close look, maybe just replace it and check the RD hanger. It rode well enough on the rest of the ride that I felt comfortable going over 30mph.

thanks for the inputs/responses.

[dddd]

Modern bikes being so light, I've seen cases of rear wheel pulling out due to the dropout not settling fully over the axle as the QR was tightened.
The sprung chain tension has to be overcome by downward force on the frame in order for the axle to fully engage in the dropout slot, so I always add some shoulder weight on the saddle as I secure the rear QR lever.
This wasn't a problem in the old days when bikes weighed more.

Having a longer stem increases the chances of tipping over forward when for example a chain snaps while the rider is honking off of the saddle.